Updated on 2024/12/21

写真a

 
KATAOKA, Jun
 
Affiliation
Faculty of Science and Engineering, School of Advanced Science and Engineering
Job title
Professor
Degree
Doctor of Science ( University of Tokyo )

Research Experience

  • 2021.10
    -
    Now

    JST 戦略的創造研究推進事業 ERATO   片岡ラインX線ガンマ線イメージング   研究総括

  • 2014.04
    -
    Now

    Professor, Waseda University

  • 2017.04
    -
    2019.03

    JAXA visiting professor

  • 2009.04
    -
    2014.03

    Associate Professor, Waseda University

  • 2006.04
    -
    2010.03

    JST project leader

  • 2007.04
    -
    2009.03

    Assistant Professor, Tokyo Tech

  • 2001.04
    -
    2007.03

    Reseach Associate, Tokyo Tech

  • 2000.04
    -
    2001.03

    JSPS fellow (PD)

  • 1997.04
    -
    2000.03

    JSPS fellow (DC1)

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Education Background

  • 1997.04
    -
    2000.03

    University of Tokyo   Faculty of Science, Depatment of Physics  

  • 1995.04
    -
    1997.03

    University of Tokyo   Faculty of Science, Department of Physics  

  • 1991.04
    -
    1995.03

    University of Tokyo   Faculty of Science   Department of Physics  

Committee Memberships

  • 2023.04
    -
    Now

    JST ASPIRE  JST expert advisor

  • 2023.11
    -
    2024.09

    ノーベル物理学賞ノミネート委員 (2024)

  • 2021.01
    -
    2021.09

    ノーベル物理学賞ノミネート委員 (2021)

  • 2013
    -
    2014

    宇宙線研究者会議CRC・将来計画検討小委員会メンバー(2013-2014年度)

  • 2012.01
    -
    2012.09

    ノーベル物理学賞ノミネート委員 (2012)

  • 2010
    -
    2011

    高エネルギー宇宙物理連絡会 運営委員 (2010-2011年度)

  • 2010
    -
    2011

    日本物理学会・宇宙線分科会・領域運営委員 (2010-2011年度)

  • 2010
    -
    2011

    応用物理学会・放射線分科会 幹事 (2010-2011年度)

  • 2010
    -
    2011

    日本学術振興会・特別研究員・面接委員 (2010-2011年度)

  • 2008
    -
     

    日本応用物理学会  正会員

  • 2007.01
    -
    2007.09

    ノーベル物理学賞ノミネート委員 (2007)

  • 1995
    -
     

    日本天文学会  正会員

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Professional Memberships

  •  
     
     

    医学物理学会

  •  
     
     

    日本天文学会

  •  
     
     

    日本物理学会

  •  
     
     

    日本応用物理学会

Research Areas

  • Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics / Astronomy / Medical systems / Radiological sciences / Nanobioscience / Quantum beam science

Research Interests

  • High-energy Astrophysics

  • Medical Physics

  • 薬物伝達(ドラッグデリバリー)可視化システム

  • X線ガンマ線イメージング

  • R&D of novel radiation detector

  • コンプトンカメラ

  • 多色スペクトラルCT

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Awards

  • 科学技術分野・文部科学大臣表彰 (研究部門)

    2024.04  

  • Key Researcher, Waseda University

    2016.04  

  • WASEDA RESEARCH AWARD(High-Impact Publication)

    2014.12  

  • Best Paper Award, The Astronomical Society of Japan

    2013.10  

  • The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology

    2012.04  

  • NASA Group Achievement Award

    2009.04  

  • Research Award, The Astronomical Society of Japan

    2004.10  

  • CRC, JPS, Research Award

    2002.03  

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Media Coverage

  • 雷発生時のガンマ線、新潟十日町・松代で世界初の画像化に成功

    Newspaper, magazine

    新潟日報(朝刊)  

    2022.12

  • 早大ら、放射化イメージングで薬物動態の可視化へ

    Internet

    Optronics News Letter  

    2022.11

  • 戦略的創造研究推進事業における 令和3年度新規研究総括および研究領域の決定について

    Internet

    2021.10

  • Galaxy-Size Bubbles Discovered Towering Over the Milky Way

    Newspaper, magazine

    Quanta Magagize  

    2021.01

  • X線からガンマ線まで同時に可視化~早大・阪大が共同

    Newspaper, magazine

    科学新聞  

    2020.10

  • 輝くブラックホールの謎 ~ 銀河中心部繰り返し爆発か

    Newspaper, magazine

    日本経済新聞(日刊)  

    2019.09

  • 天の川銀河「巨大ガンマ線バブル」の謎に迫る

    academist Journal  

    2018.08

  • 早大・東大・金沢大・理研、銀河中心「巨大ガンマ線バブル」の謎を解明 -1000万年前の大爆発をX線で検証

    日経新聞電子版  

    日経新聞電子版  

    2018.07

  • 4.4MeVのガンマ線可視化 ― 早大が小型カメラ開発

    科学新聞  

    2018.06

  • ガンマ線検出のカメラ~陽子線治療など応用 早大など開発

    日経産業新聞  

    2018.06

  • 見えない光で未知を観る!

    BSジャパン   「科学ミチル 世界は未知で満ちている」  

    BSジャパン7ch : 木曜夜 8:55  

    2018.03

  • 研究者の横顔

    NTT   NTTファシリティーズ・ジャーナル  

    2017.11

  • Medical gamma-ray camera is now palm-sized

    Science Daily  

    2017.05

  • 世界最軽量580グラム実現 ガンマ線可視化カメラ

    科学新聞   科学新聞  

    2017.05

  • 早大など、ガンマ線を3D画像に 手のひら大のカメラ

    日経新聞   日経新聞全国版  

    2017.05

  • セシウムの分布可視化―早大、ドローン使い空撮

    日経産業新聞   日経産業新聞  

    2016.09

  • 星空案内人 ― 福島で活躍中 コンプトンカメラ

    山形新聞   山形新聞  

    2016.07

  • ガンマ線撮像用コンプトンカメラの高性能化に成功 ~除染のさらなる効率化、環境調査、医療、理学応用へ期待~

    静岡第一テレビ、日経産業新聞、日刊工業新聞  

    2014.07

  • セシウム強度 効率測定~浜ホト・早大 ガンマ線カメラ

    Newspaper, magazine

    日本経済新聞(日刊)  

    2013.09

  • 数分で放射線画像化

    Newspaper, magazine

    朝日新聞(日刊)  

    2013.09

  • ガンマ線を素早く画像化-「福島第一」除染に威力

    Newspaper, magazine

    中日新聞  

    2013.09

  • 新種の「毒蜘蛛パルサー」発見

    読売新聞、東京新聞、中日新聞  

    2012.03

  • Waseda University's Fermi LAT Team

    Newspaper, magazine

    Fermi News Letter  

    2010.05

  • フェルミ衛星で銀河に付随する「巨大な粒子雲」からのガンマ線を発見

    科学新聞  

    2010.04

  • LuAG結晶用い放射線検出器開発ー次世代がん診断装置向け

    化学工業新聞  

    2009.07

  • フェルミ衛星が新種のガンマ線銀河を発見

    毎日新聞  

    2009.06

  • NASA’s Fermi Finds Gamma-Ray Galaxy Surprises

    Internet

    NASA  

    2009.05

  • 解像度5倍 がん早期発見 ― 光センサー小さく

    Newspaper, magazine

    日経産業新聞  

    2008.05

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Papers

  • Scintillation of polyester fabric and clothing via proton irradiation and its utilization in surface imaging of proton pencil beams

    Seiichi Yamamoto, Tomohiro Yamashita, Masao Yoshino, Kei Kamada, Akira Yoshikawa, Teiji Nishio, Jun Kataoka

    Scientific Reports   14 ( 1 )  2024.12

     View Summary

    In the realm of radiation therapy, a conspicuous obstacle lies in the dearth of external observation concerning radiation beams aimed at the patient. While real-time monitoring of such beams on the patient's surface during therapy holds promise, the imaging of particle beams has thus far proven to be a formidable task. Here, we show our discovery of polyester fabrics and cloths as auspicious scintillating materials, ideally suited for the visualization of radiation beams upon the patient's surface. The light output of polyester fabrics ranged from 10 to 20% of that observed in plastic scintillators. When exposed to spot scanning proton beams, clear beam spots emerged on the surface of the polyester cloths. The movement of these scanning beams was effectively captured using a CMOS camera in a light-shield-free with lights-off environment. The resulting images provided a means for evaluating spills of the proton beams. The inherent flexibility of polyester fabrics and clothing enhances their appeal for applications in the intricate landscape of radiation therapy, promising a bright future for surface beam imaging endeavors.

    DOI PubMed

    Scopus

  • Development of a GAGG gamma camera for the imaging of prompt gammas during proton beam irradiation.

    Seiichi Yamamoto, Tomohiro Yamashita, Yusuke Kobashi, Takuya Yabe, Kohei Nakanishi, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)   127   104847 - 104847  2024.10  [International journal]

     View Summary

    Prompt gammas imaging (PGI) is a promising method for observing a beam's shape and estimating the range of the beam from outside a subject. However 2-dimensional images of prompt gammas (PGs) during irradiation of protons were still difficult to measure. To achieve PGI, we developed a new gamma camera and imaged PGs while irradiating a phantom by proton beams. We also simultaneously measured prompt X-ray (PX) images with an X-ray camera from opposed direction and compared the images. The developed gamma camera uses a 10 mm thick GAGG block optically coupled to a flat panel photomultiplier tube (FP-PMT), and it is contained in a 20 mm thick tungsten container with a pinhole collimator attached. A poly-methyl-methacrylate (PMMA) block was irradiated by proton beams with total number of the protons similar to the clinical level, and the gamma camera imaged PGs and X-ray camera imaged PXs simultaneously. For all of the tested beams, we could measure the beam shapes of the PGs and the PXs and the ranges could also be estimated from the images. For both PG and PX images, time sequential images and accumulated images could be derived. We confirmed that the PGI using our developed gamma camera, as well as PXI, is promising for beam imaging and range estimation in proton therapy.

    DOI PubMed

    Scopus

  • Development and performance evaluation of a thin GAGG:Ce scintillator plate for high resolution synchrotron radiation X-ray imaging

    Masao Yoshino, Seiichi Yamamoto, Kohei Nakanishi, Katsunori Yogo, Kei Kamada, Nanase Koshikawa, Jun Kataoka, Akira Yoshikawa

    Journal of Instrumentation   19 ( 10 ) P10030 - P10030  2024.10

     View Summary

    Abstract

    Scintillator-based X-ray imaging detectors are pivotal in numerous scientific and practical domains, including medical imaging, food and device inspection, and security monitoring. Recent advancements have spurred interest in 4D X-ray imaging using synchrotron radiation, necessitating higher temporal resolutions. Consequently, this places stringent demands on X-ray detector technology, especially when X-ray energy exceeds 20 keV. The selection of a suitable scintillator material is crucial for achieving optimal timing resolution, yet it poses a significant challenge in dynamic X-ray imaging. This study delves into the optimization of scintillator properties and their impact on spatial resolution and light output, elucidating the performance of Ce-doped Gd3Ga3Al2O12 (GAGG:Ce) scintillators for X-ray imaging applications. We developed a micro X-ray imaging detector using a 100 μm-thick GAGG:Ce scintillator plate and conducted X-ray imaging tests at the Aichi SR facility. The results demonstrated that the resolution, quantified as the chart slit width at a contrast transfer function (CTF) value of 10%, reached 2 ∼ 3 μm with a 4× lens, 0.52 μm± 0.03 μm with a 20× lens, and 0.42 μm± 0.01 μm with a 40× lens. Although the results of this study did not achieve a spatial resolution nearing the effective pixel size of the 40× lens, the text also elucidates the underlying reasons for this limitation. Furthermore, we compared the X-ray sensitivity of our GAGG:Ce scintillator plate with that of a commercial LuAG:Ce scintillator, revealing an approximately 1.5-fold increase in light output. As a demonstration, transmission images of dried small fish were captured using the GAGG:Ce scintillator plate and the developed X-ray imaging system. These findings highlight the potential of the X-ray imaging detector devised in this study for future generations of X-ray imaging applications.

    DOI

  • Development of a single photon emission microscope system with ∼200 μm spatial resolution

    Seiichi Yamamoto, Kohei Nakanishi, Jun Kataoka

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1067   169673 - 169673  2024.10

    DOI

    Scopus

  • MeV gamma-ray detector on the 50-kg class satellite

    Kazuo Tanaka, Jun Kataoka, Ryoji Iwashita, Ryohei Mori, Tomoya Suga, Shojun Ogasawara, Moeri Tao, Yoichi Yatsu, Chujo Toshihiro, Shinichiro Takeda, Mitsunobu Onishi

    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray     98 - 98  2024.08

    DOI

    Scopus

  • Challenge of 50 kg-class satellite to open up MeV gamma-ray astronomy

    J. Kataoka, R. Iwashita, K.S. Tanaka, R. Mori, S. Ogasawara, T. Suga, N. Koshikawa, K. Watanabe, M. Yasuda, H. Kobayashi, D. Kobayashi, K. Otsubo, A. Ohira, Y. Amaki, Y. Arai, K. Tashiro, Y. Ozeki, Y. Kawaguchi, D. Yoshimura, H. Yoshida, K. Takahashi, Y. Yatsu, T. Chujo, H. Nakanishi, M. Onishi, S. Takeda

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1065   169518 - 169518  2024.08

    DOI

    Scopus

  • Development of a phoswich imaging detector to simultaneously acquire neutron and gamma photon images

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Hiroki Tanaka, Jun Kataoka

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1065   169484 - 169484  2024.08

    DOI

    Scopus

  • Multi-energy in-vivo imaging of multiple contrast agents in a mouse using MPPC-based photon-counting CT

    Daichi Sato, Makoto Arimoto, Ayumi Ishiguro, Fitri Lucyana, Takahiro Tomoda, Kenichiro Okumura, Hiroki Kawashima, Satoshi Kobayashi, Kazuhiro Murakami, Jun Kataoka, Mayu Sagisaka, Shinsuke Terazawa, Satoshi Shiota

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1064   169337 - 169337  2024.07

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • ComptonNet: A direct reconstruction model for Compton camera

    S. Sato, K. S. Tanaka, J. Kataoka

    Applied Physics Letters   124 ( 25 )  2024.06

     View Summary

    A Compton camera is a gamma-ray imaging device, especially in the sub-mega-electron volt to higher than mega-electron volt range. Compton cameras have recently attracted attention as an environmental survey tool. However, owing to their limited sensitivity, Compton camera images often suffer from various artifacts, especially when the event statistics are low. To address this challenge, several deep learning models have been proposed to enhance the quality of reconstructed images with limited statistics. However, during the event selection phase of a typical Compton camera image reconstruction, a significant number of events that potentially reflect the source distribution are generally discarded. Effective utilization of these discarded events has the potential to estimate an accurate source distribution from limited statistical data. Thus, we initially developed ComptonNet-v1, a framework designed to directly estimate source distribution by integrating all measured events into a single model. To explicitly implement the difference in contribution between events that interact solely with scatterers, solely with absorbers, or with both, we developed ComptonNet-v2, which integrates these events individually. Consequently, our proposed models exhibited superior performance in both quantitative and qualitative assessments compared with existing models, even under low event statistics. In the future, we plan to implement a more memory-efficient model to estimate the distribution of complex source shapes.

    DOI

    Scopus

  • Experimental concept validation of a proton therapy range verification system using scattered proton measurements

    S. Sato, H. Yokokawa, M. Sagisaka, Y. Okazaki, R. Iwashita, S. Yoshida, K. S. Tanaka, S. Yamamoto, T. Yamashita, Y. Kobashi, J. Kataoka

    Applied Physics Letters   124 ( 21 )  2024.05

     View Summary

    In recent years, the application of positron emission tomography (PET) for the dose range verification of proton therapy has been proposed. However, the positron distribution is determined by the nuclear reaction cross section; hence, PET may not accurately reflect the dose range primarily influenced by ionization. Consequently, a proton dose range verification system based on scattered proton measurements has been suggested owing to the similarity in the reaction cross section between Rutherford scattering and ionization. While previous investigations have only verified the feasibility of dose range estimation through simple simulations, the objective of this study is to demonstrate this feasibility through experimental investigation. In this paper, we established an experimental framework for capturing scattered protons and introduced an algorithm that compares measured signal patterns with a reference database to estimate the dose range. A therapeutic beam was irradiated onto the abdominal region of a human phantom, and scattered protons were measured using scintillation detectors placed on the phantom surface. Consequently, the dose range was estimated with error margins of 4.22 ± 3.68 and 0.60 ± 1.03 mm along the beam axis and perpendicular directions to the Bragg peak, respectively. While providing the same level of Bragg peak positioning accuracy as conventional methods, our system features small size, cost-effectiveness, and system simplicity. One notable limitation of our method is the challenge in achieving precise detector positioning, which is crucial for accurate dose range estimation. Future research will focus on improving detector-position accuracy and exploring advanced algorithms for signal analysis to further refine dose range estimations.

    DOI

    Scopus

  • The Calorimetric Electron Telescope (CALET) on the International Space Station: Results from the first eight years on orbit

    Y. Akaike, O. Adriani, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W.R. Binns, M. Bongi, P. Brogi, A. Bruno, N. Cannady, G. Castellini, C. Checchia, M.L. Cherry, G. Collazuol, G.A. de Nolfo, K. Ebisawa, A.W. Ficklin, H. Fuke, S. Gonzi, T.G. Guzik, T. Hams, K. Hibino, M. Ichimura, W. Ishizaki, M.H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H.S. Krawczynski, J.F. Krizmanic, P. Maestro, P.S. Marrocchesi, A.M. Messineo, J.W. Mitchell, S. Miyake, A.A. Moiseev, M. Mori, N. Mori, H.M. Motz, K. Munakata, S. Nakahira, J. Nishimura, M. Negro, S. Okuno, J.F. Ormes, S. Ozawa, L. Pacini, P. Papini, B.F. Rauch, S.B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J.P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W.V. Zober

    Advances in Space Research    2024.04

    DOI

    Scopus

  • Construction and initial performance evaluation of a newly developed plant PET system

    Seiichi Yamamoto, Hiroshi Watabe, Mitsutaka Yamaguchi, Nobuo Suzui, Naoki Kawachi, Jun Kataoka

    Journal of Instrumentation   19 ( 04 )  2024.04  [Refereed]

    DOI

  • A method for estimating the incident directions of alpha particles in 2-dimensional trajectory images in a GAGG plate

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   19 ( 04 ) T04010 - T04010  2024.04

     View Summary

    Abstract

    An imaging technique utilizing a scintillator plate in conjunction with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera shows promise for capturing high-resolution trajectory images. Nevertheless, in the 2-dimensional trajectory images, the incident directions of the alpha particles entering the scintillator plate remained unknown due to the line-shaped trajectories. To elucidate the incident directions in our trajectory images, we conducted experiments capturing trajectory images of alpha particles under off-focus conditions. To capture off-focus images of alpha particles, we systematically varied the distance between the GAGG plate and the lens during imaging using an americium-241 (Am-241) source. Through images obtained at different distances between the GAGG plate and the lens, we successfully acquired trajectory images with varying degrees of off-focus, revealing that trajectory images focused on the upper surface of the GAGG plate exhibited blurred and wider trajectories in the deeper regions, making the incident directions of the alpha particles evident. We conclude that the proposed off-focus method for trajectory imaging of alpha particles holds promise for estimating the incident directions in the trajectory images.

    DOI

  • A novel method for efficiently measuring the non-proportionality of scintillators between light output and alpha particle energies from 1.8 MeV to 5.2 MeV

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   19 ( 04 ) P04011 - P04011  2024.04

     View Summary

    Abstract

    It is known that scintillators exhibit non-proportional behavior between light output and the energy of gamma photons or beta particles. However, the non-proportionality between light output in scintillators and the energy of alpha particles has not been extensively measured, likely due to the challenges associated with preparing alpha particles with varying energies. To address this issue, we propose a novel method to modulate the energy of alpha particles using an americium-241 (Am-241) source covered with different numbers of Mylar films. By irradiating various scintillators, including GAGG, GGAG, YAP(Ce), and plastic scintillator, with alpha particles of different energies, we measured and evaluated the non-proportional response of these scintillators. We then compared the measured response as a function of incident energy to a simulation, which assumes a proportional response to evaluate the non-proportionality. For all the scintillators tested, non-proportionality was observed; the light output per MeV at 1.8 MeV ranged from 0.60 to 0.81 of the values observed at 5.2 MeV. The non-proportional response was largest for plastic scintillator (0.60) and smallest for GAGG (0.81). We conclude that the proposed method could be an efficient means of measuring the non-proportionality of scintillators between light output and alpha particle energies

    DOI

  • A triple-imaging-modality system for simultaneous measurements of prompt gamma photons, prompt x-rays, and induced positrons during proton beam irradiation

    Seiichi Yamamoto, Hiroshi Watabe, Kohei Nakanishi, Takuya Yabe, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Masayasu Miyake, Kazuo S Tanaka, Jun Kataoka

    Physics in Medicine & Biology   69 ( 5 ) 055012 - 055012  2024.02

     View Summary

    Abstract

    Objective. Prompt gamma photon, prompt x-ray, and induced positron imaging are possible methods for observing a proton beam’s shape from outside the subject. However, since these three types of images have not been measured simultaneously nor compared using the same subject, their advantages and disadvantages remain unknown for imaging beam shapes in therapy. To clarify these points, we developed a triple-imaging-modality system to simultaneously measure prompt gamma photons, prompt x-rays, and induced positrons during proton beam irradiation to a phantom. Approach. The developed triple-imaging-modality system consists of a gamma camera, an x-ray camera, and a dual-head positron emission tomography (PET) system. During 80 MeV proton beam irradiation to a polymethyl methacrylate (PMMA) phantom, imaging of prompt gamma photons was conducted by the developed gamma camera from one side of the phantom. Imaging of prompt x-rays was conducted by the developed x-ray camera from the other side. Induced positrons were measured by the developed dual-head PET system set on the upper and lower sides of the phantom. Main results. With the proposed triple-imaging-modality system, we could simultaneously image the prompt gamma photons and prompt x-rays during proton beam irradiation. Induced positron distributions could be measured after the irradiation by the PET system and the gamma camera. Among these imaging modalities, image quality was the best for the induced positrons measured by PET. The estimated ranges were actually similar to those imaged with prompt gamma photons, prompt x-rays and induced positrons measured by PET. Significance. The developed triple-imaging-modality system made possible to simultaneously measure the three different beam images. The system will contribute to increasing the data available for imaging in therapy and will contribute to better estimating the shapes or ranges of proton beam.

    DOI

    Scopus

  • Multi-pixel photon counter-based gamma camera with pinhole collimator to locate Cs-137 sources at high dose rates for the Fukushima nuclear power plant

    T. Tomoda, M. Arimoto, T. Mizuno, D. Sato, F. Lucyana, J. Kataoka, M. Kato, J. Ishii, T. Sawano, D. Yonetoku, S. Terazawa, S. Shiota

    Journal of Instrumentation   19 ( 2 )  2024.02

     View Summary

    The Fukushima Daiichi Nuclear Power Plant was severely damaged during the 2011 Great East Japan Earthquake. However, the ongoing decommissioning work has been limited by the complexity of the reactor’s internal structure and very high radiation levels; locating radioactive sources is essential for efficient decommissioning. Conventional gamma cameras are mainly designed for low radiation dose (∼mSv/h) and using them under high radiation conditions is difficult (>Sv/h). Therefore, we developed a pinhole gamma camera with a gamma radiation detector consisting of a high-speed YGAG scintillator array and multi-pixel photon counters to locate radioactive sources at high dose rates. The gamma-ray photon signals captured by the developed two-dimensional detector array can be processed at a speed as high as >1 MHz/pixel using the developed large scale integrated circuit. Herein, we report the measurement results of an extremely high radioactivity of137Cs (∼34 TBq) using the developed gamma camera. The gamma-ray source position was determined using an angular size of ∼4.6◦, with images obtained at 2 m from the radioactive source and at a dose rate of 0.3 Sv/h. The direct gamma rays with a photoelectric peak at 662 keV and scattered component of gamma rays can be distinguished from the measured spectrum. We also characterize the imaging capability of the137Cs depending on the detected gamma-ray energies and discuss related details.

    DOI

    Scopus

  • Sparse-view image reconstruction with total-variation minimization applied to sparsely sampled projection data from SiPM-based photon-counting CT

    D. Sato, M. Arimoto, J. Kotoku, H. Kawashima, S. Kobayashi, K. Okumura, K. Murakami, F. Lucyana, T. Tomoda, J. Kataoka, M. Sagisaka, S. Terazawa, S. Shiota

    Journal of Instrumentation   19 ( 02 ) C02010 - C02010  2024.02  [Refereed]

     View Summary

    Abstract

    We constructed a sparse-view computed tomography (CT) system that combines a compressed sensing (CS)-based image-reconstruction algorithm and SiPM-based photon-counting (PC) CT. CS-based image-reconstruction algorithms have been extensively studied for X-ray CT image reconstruction using fewer projections because they are expected to reduce CT imaging time and radiation exposure while maintaining CT image quality. In most previous studies, CS-based image-reconstruction algorithms have been applied to data obtained through numerical simulations or conventional dual-energy CT. However, studies on PC-CT have been scarce. Therefore, we applied a CS-based image-reconstruction algorithm to the projection data obtained using our previously established SiPM-based PC-CT system and evaluated its image quality. We prepared static phantoms equivalent to iodine-containing contrast agents and a mouse model injected with iodine-containing contrast agents as subjects. Thereafter, CT scanning was performed. The obtained projection data were downsampled to simulate a sparse-view situation, and a CS-based image-reconstruction algorithm with total-variation minimization was applied. Consequently, sparse-view CT images were successfully reconstructed, and the image quality was maintained even after downsampling the projection data (downsampling ratios of 1/10 and 1/2 for the rod phantom and mouse model, respectively). Thus, the imaging time and exposure dose could be remarkably reduced (by a factor of 10 or 2), indicating that the CS-based image-reconstruction algorithm is effective for PC-CT.

    DOI

  • Range and light output measurements of trajectory images in a GAGG plate with different alpha particle energies

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   19 ( 01 ) P01010 - P01010  2024.01

     View Summary

    Abstract

    An imaging method that utilizes a scintillator plate combined with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera shows promise for obtaining high-resolution trajectory images. However, it is not yet clear whether the ranges of the trajectory images change with the energy of the alpha particles. Additionally, it remains unclear whether the intensity of the trajectory images is affected by the energy of the alpha particles. To address these questions in our trajectory imaging research, we conducted experiments to capture trajectory images of alpha particles with varying energy levels. To generate alpha particles with different energies, we modulated the energy using an americium-241 (Am-241) source covered with varying numbers of Mylar films. With this alpha source and imaging system, we successfully captured trajectory images with different alpha particle energies and were able to assess the ranges and intensities of these trajectories at various energy levels. The estimated ranges from the measured images with different alpha particle energies closely matched the results obtained through simulations. However, it's worth noting that the light output, as evaluated for the measured trajectory images, was slightly lower than the simulated results at lower energy levels probably due to the non-proportionality of the GAGG plate with respect to alpha particle energies.

    DOI

  • A large field-of-view angled panel detector for the development of a plant PET system

    Seiichi Yamamoto, Hiroshi Watabe, Mitsutaka Yamaguchi, Nobuo Suzui, Naoki Kawachi, Jun Kataoka

    Journal of Instrumentation   19 ( 1 ) T01002  2024.01  [Refereed]

     View Summary

    <jats:title>Abstract</jats:title>
    <jats:p>In plant research, positron emission tomography (PET) is
    sometimes employed for physiological studies of plants. However, due
    to the generally high cost of PET systems, their application in
    plant research centers can be challenging. Furthermore, the
    configurations of commercial PET systems might not always align well
    with the requirements of plant research. To address these issues, we
    have taken the initial steps towards a solution by developing a
    large field-of-view (LFOV) angled panel detector intended for the
    development of a plant PET system. This panel detector is composed
    of two gadolinium orthosilicate (GSO) scintillator blocks, an angled
    light guide, and four flat panel photomultiplier tubes
    (FP-PMTs). The GSO pixel size used in the scintillator block
    measures
    2.65 mm (radial)× 2.85 mm (axial)×
    15.0 mm, arranged in a configuration of
    16 (radial)× 32 (axial) to form a scintillator
    block with overall dimensions of
    44.0 mm (radial)× 94.4 mm (axial)×
    15 mm (depth). By implementing an angled light guide, the
    two scintillator blocks were positioned at a 22.5-degree angle,
    resulting in the creation of a LFOV angled panel detector. This
    specific angle allowed for the arrangement of 16 scintillator blocks
    in a hexadecagonal shape using 8 panel detectors when arranged in a
    circular configuration. We successfully constructed a panel detector
    with an approximate field-of-view of 10 cm× 10 cm
    and conducted a comprehensive performance evaluation. Upon
    irradiating the panel detector with 511 keV gamma photons, nearly
    all 1024 GSO pixels were accurately resolved in the position
    histogram, displaying minimal distortion, and exhibiting an average
    peak-to-valley ratio of 5.0. Additionally, the energy resolution
    achieved was 14% full width at half maximum (FWHM). The resulting
    LFOV angled panel detector holds considerable promise for the use
    within a cost-effective, user-friendly as well as high performance
    plant PET system.</jats:p>

    DOI

  • Optimization of a YAP(Ce) prompt X-ray camera for imaging with spot scanning proton beams at clinical dose levels

    Seiichi Yamamoto, Tomohiro Yamashita, Yusuke Kobashi, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   18 ( 12 )  2023.12

     View Summary

    Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing the beam shape from outside a subject. However, it has sometimes been necessary to conduct such imaging at a higher dose than the clinical level to acquire images with acceptable quality. To solve this problem, we optimized a prompt X-ray imaging system to use for spot scanning proton therapy system. The new camera had more than one order higher sensitivity to image several types of beams, including those at the clinical dose level. The optimized prompt X-ray imaging system uses a 4 mm diameter pinhole collimator to increase sensitivity, and it is combined with a larger YAP(Ce) scintillator to increase the magnification ratio and thus improve spatial resolution. We used a list-mode data-acquisition system with high count rate capability. Prompt X-ray images were acquired by irradiating a water phantom with proton beams from the spot scanning proton therapy system. Measurements were taken for pencil beams, spread-out Bragg peak (SOBP) beams, and a beam utilized in actual clinical therapy. For all of the beams, we could measure scanning spot images within a spill and evaluate the ranges for the accumulated images at the clinical dose level. From the list-mode data, we measured the temporarily altered positions of the scanning beams as well as the accumulations of the prompt X-ray images. The optimized prompt X-ray imaging system could improve sensitivity while maintaining better spatial resolution. The new system realized prompt X-ray imaging at the clinical dose level and holds promise for future clinical imaging of prompt X-rays.

    DOI

    Scopus

  • A comparative study of EM-CCD and CMOS cameras for particle ion trajectory imaging

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Katsunori Yogo, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Applied Radiation and Isotopes     111143 - 111143  2023.12

    DOI

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    2
    Citation
    (Scopus)
  • The Third Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars

    D. A. Smith, S. Abdollahi, M. Ajello, M. Bailes, L. Baldini, J. Ballet, M. G. Baring, C. Bassa, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, B. Bhattacharyya, E. Bissaldi, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, M. Burgay, T. H. Burnett, R. A. Cameron, F. Camilo, R. Caputo, P. A. Caraveo, E. Cavazzuti, G. Chiaro, S. Ciprini, C. J. Clark, I. Cognard, A. Corongiu, P. Cristarella Orestano, M. Crnogorcevic, A. Cuoco, S. Cutini, F. D’Ammando, A. de Angelis, M. E. DeCesar, S. De Gaetano, R. de Menezes, J. Deneva, F. de Palma, N. Di Lalla, F. Dirirsa, L. Di Venere, A. Domínguez, D. Dumora, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, C. Flynn, A. Franckowiak, P. C. C. Freire, Y. Fukazawa, P. Fusco, G. Galanti, V. Gammaldi, F. Gargano, D. Gasparrini, F. Giacchino, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, L. Guillemot, S. Guiriec, M. Gustafsson, A. K. Harding, E. Hays, J. W. Hewitt, D. Horan, X. Hou, F. Jankowski, R. P. Johnson, T. J. Johnson, S. Johnston, J. Kataoka, M. J. Keith, M. Kerr, M. Kramer, M. Kuss, L. Latronico, S.-H. Lee, D. Li, J. Li, B. Limyansky, F. Longo, F. Loparco, L. Lorusso, M. N. Lovellette, M. Lower, P. Lubrano, A. G. Lyne, Y. Maan, S. Maldera, R. N. Manchester, A. Manfreda, M. Marelli, G. Martí-Devesa, M. N. Mazziotta, J. E. McEnery, I. Mereu, P. F. Michelson, M. Mickaliger, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, M. Negro, R. Nemmen, L. Nieder, E. Nuss, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, M. Palatiello, D. Paneque, G. Panzarini, A. Parthasarathy, M. Persic, M. Pesce-Rollins, R. Pillera, H. Poon, T. A. Porter, A. Possenti, G. Principe, S. Rainò, R. Rando, S. M. Ransom, P. S. Ray, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, N. Renault-Tinacci, R. W. Romani, M. Sánchez-Conde, P. M. Saz Parkinson, L. Scotton, D. Serini, C. Sgrò, R. Shannon, V. Sharma, Z. Shen, E. J. Siskind, G. Spandre, P. Spinelli, B. W. Stappers, T. E. Stephens, D. J. Suson, S. Tabassum, H. Tajima, D. Tak, G. Theureau, D. J. Thompson, O. Tibolla, D. F. Torres, J. Valverde, C. Venter, Z. Wadiasingh, N. Wang, N. Wang, P. Wang, P. Weltevrede, K. Wood, J. Yan, G. Zaharijas, C. Zhang, W. Zhu

    The Astrophysical Journal   958 ( 2 ) 191 - 191  2023.11

     View Summary

    Abstract

    We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems colocated with LAT sources also likely harbor gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and candidates, 10% of all known pulsars, compared to ≤11 known before Fermi. Half of the gamma-ray pulsars are young. Of these, the half that are undetected in radio have a broader Galactic latitude distribution than the young radio-loud pulsars. The others are MSPs, with six undetected in radio. Overall, ≥236 are bright enough above 50 MeV to fit the pulse profile, the energy spectrum, or both. For the common two-peaked profiles, the gamma-ray peak closest to the magnetic pole crossing generally has a softer spectrum. The spectral energy distributions tend to narrow as the spindown power $\dot{E}$ decreases to its observed minimum near 1033 erg s−1, approaching the shape for synchrotron radiation from monoenergetic electrons. We calculate gamma-ray luminosities when distances are available. Our all-sky gamma-ray sensitivity map is useful for population syntheses. The electronic catalog version provides gamma-ray pulsar ephemerides, properties, and fit results to guide and be compared with modeling results.

    DOI

    Scopus

    51
    Citation
    (Scopus)
  • Estimating blurless and noise-free Ir-192 source images from gamma camera images for high-dose-rate brachytherapy using a deep-learning approach

    Kohei Nakanishi, Seiichi Yamamoto, Takuya Yabe, Katsunori Yogo, Yumiko Noguchi, Kuniyasu Okudaira, Naoki Kawachi, Jun Kataoka

    Biomedical Physics &amp; Engineering Express    2023.11

     View Summary

    Abstract

    Objective: Precise monitoring of the position and dwell time of iridium-192 (Ir-192) during high-dose-rate (HDR) brachytherapy is crucial to avoid serious damage to normal tissues. Source imaging using a compact gamma camera is a potential approach for monitoring. However, images from the gamma camera are affected by blurring and statistical noise, which impact the accuracy of source position monitoring. This study aimed to develop a deep-learning approach for estimating ideal source images that reduce the effect of blurring and statistical noise from experimental images captured using a compact gamma camera.&amp;#xD;Approach: A double pix2pix model was trained using the simulated gamma camera images of an Ir-192 source. The first model was responsible for denoising the Ir-192 images, whereas the second model performed super resolution. Trained models were then applied to the experimental images to estimate the ideal images. &amp;#xD;Main results: At a distance of 100 mm between the compact gamma camera and the Ir-192 source, the difference in full width at half maximum (FWHM) between the estimated and actual source sizes was approximately 0.5 mm for a measurement time of 1.5 s. This difference has been improved from approximately 2.7 mm without the use of DL. Even with a measurement time of 0.1 s, the ideal images could be estimated as accurately as in the 1.5 s measurements. This method consistently achieved accurate estimations of the source images at any position within the field of view; however, the difference increased with the distance between the Ir-192 source and the compact gamma camera.&amp;#xD;Significance: The proposed method successfully provided estimated images from the experimental images within errors smaller than 0.5 mm at 100 mm. This method is promising for reducing blurring and statistical noise from the experimental images, enabling precise real-time monitoring of Ir-192 sources during HDR brachytherapy.

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Direct Measurement of the Spectral Structure of Cosmic-Ray <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mtext>Electrons</mml:mtext><mml:mo>+</mml:mo><mml:mtext>Positrons</mml:mtext></mml:mrow></mml:math> in the TeV Region with CALET on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   131 ( 19 )  2023.11

    DOI

  • Development of an event-by-event based Li–ZnS(Ag) neutron imaging detector with selective neutron detection capability

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Hiroki Tanaka, Jun Kataoka

    Applied Radiation and Isotopes     111084 - 111084  2023.10

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  • Sub-micrometer real-time imaging of trajectory of alpha particles using GAGG plate and CMOS camera

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Katsunori Yogo, Kei Kamada, Akira Yoshikawa, Nanase Koshikawa, Jun Kataoka

    Journal of Instrumentation   18 ( 10 ) T10003 - T10003  2023.10

     View Summary

    Abstract

    High-resolution and real-time imaging of the trajectories of alpha particles is desired in nuclear medicine and nuclear engineering. Although an imaging method using a scintillator plate combined with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera is a possible method of obtaining high-resolution trajectory images, the spatial resolution of the system is limited to ∼2 μm. To overcome the spatial resolution limitations of this method on trajectory imaging, we used a cooled complementally metal oxide (CMOS) camera in which the sensor had a much larger number of pixels, which were also smaller. Using the CMOS camera based imaging system, we could measure the trajectories of alpha particles in real time with the spatial resolution of 0.34 μm FWHM. With smoothing of the images to reduce image noise, spatial resolution was still kept to less than 0.75 μm. We conclude that this CMOS camera-based alpha-particle trajectory-imaging system is promising for alpha-particle or other particles imaging where ultrahigh spatial resolution is required.

    DOI

  • Ultrahigh resolution real-time trajectory imaging of neutron induced particles in a scintillator from lithium-6 plate

    Yamamoto Seiichi, Yoshino Masao, Nakanishi Kohei, Kamada Kei, Yoshikawa Akira, Kataoka Jun

    Journal of Instrumentation   18 ( 10 ) T10002 - T10002  2023.10

     View Summary

    Abstract

    It is known that a lithium-6 (6Li) absorbs a neutron and is divided into a triton and an alpha particle. However, the trajectories of the produced tritons have not yet been imaged in real time and high resolution. We developed an ultrahigh-resolution imaging system that can clearly observe the trajectories of neutron induced particles in real time. The developed system is based on a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera combined with a 6Li plate and a Ce-doped Gd3Al2Ga3O12(GAGG) scintillator plate. Neutrons from a californium-252 (252Cf) source were irradiated to the 6Li plate, which produced tritons and alpha particles. The produced tritons or alpha particles entered the GAGG plate and produced scintillation light along the trajectories. The scintillation trajectories were magnified by the unit, light intensified, and imaged by the EM-CCD camera. Using our system, we could measure the elongated trajectory images of the particles in real time. Most of these trajectories had Bragg peak like shapes in the images. The average range was 15 μm and the width was 4.6 μm FWHM. From the ranges we estimated, we found that these trajectories could be attributed to the induced tritons. Consequently, the developed real time imaging system is promising for research on the ultrahigh resolution imaging of neutron produced particles.

    DOI

  • Erratum: Charge-Sign Dependent Cosmic-Ray Modulation Observed with the Calorimetric Electron Telescope on the International Space Station [Phys. Rev. Lett. 130, 211001 (2023)

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical review letters   131 ( 10 ) 109902  2023.09

     View Summary

    This corrects the article DOI: 10.1103/PhysRevLett.130.211001.

    DOI PubMed

  • The cosmic-ray electron and positron spectrum measured with CALET on the International Space Station

    Yosui Akaike, Oscar Adriani, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

    DOI

  • Results from CALorimetric Electron Telescope (CALET) Observations of Gamma-rays on the International Space Station

    Masaki Mori, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

    DOI

  • Optimization of the proton background rejection in the measurement of the electron flux at high energies with CALET on the International Space Station

    Sandro Gonzi, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

    DOI

  • Results of the Ultra-Heavy Cosmic-Ray Analysis with CALET on the International Space Station

    Wolfgang V Zober, Brian Flint Rauch, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

    DOI

  • Feasibility study on an analysis of CR helium flux with the CALET detector based on an extended acceptance

    Marco Mattiazzi, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Dark Matter Limits from the CALET Electron+Positron Spectrum with Individual Astrophysical Source Background

    Holger Motz, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Interpretation of the CALET Electron+Positron Spectrum by Astrophysical Sources

    Holger Motz, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Cosmic-Ray Modulation during Solar Cycles 24-25 Transition Observed with CALET on the International Space Station

    Shoko Miyake, Oscar Adriani, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober, Kazuoki Munakata, Yosui Akaike

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Observation of spectral structures in the flux of cosmic ray protons with CALET on the International Space Station

    Kazuyoshi Kobayashi, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • CALET Search for electromagnetic counterparts of gravitational waves in O4

    Yuta Kawakubo, Michael L. Cherry, Takanori Sakamoto, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Flux ratios of primary elements measured by CALET on the International Space Station

    Caterina Checchia, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Iron and Nickel fluxes measured by CALET on the International Space Station

    Francesco Stolzi, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.08

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  • Luminescence imaging of water irradiated by protons under FLASH radiation therapy conditions.

    Katsunori Yogo, Satoshi Kodaira, Tamon Kusumoto, Hisashi Kitamura, Toshiyuki Toshito, Hiromitsu Iwata, Masumi Umezawa, Masashi Yamada, Takuto Miyoshi, Masataka Komori, Hiroshi Yasuda, Jun Kataoka, Seiichi Yamamoto

    Physics in medicine and biology   68 ( 15 )  2023.07  [Refereed]  [International journal]

     View Summary

    Objective.FLASH radiation therapy with ultrahigh dose rates (UHDR) has the potential to reduce damage to normal tissue while maintaining anti-tumor efficacy. However, rapid and precise dose distribution measurements remain difficult for FLASH radiation therapy with proton beams. To solve this problem, we performed luminescence imaging of water following irradiation by a UHDR proton beam captured using a charge-coupled device camera.Approach. We used 60 MeV proton beams with dose rates of 0.03-837 Gy s-1from a cyclotron. Therapeutic 139.3 MeV proton beams with dose rates of 0.45-4320 Gy s-1delivered by a synchrotron-based proton therapy system were also tested. The luminescent light intensity induced by the UHDR beams was compared with that produced by conventional beams to compare the dose rate dependency of the light intensity and its profile.Main results. Luminescence images of water were clearly visualized under UHDR conditions, with significantly shorter exposure times than those with conventional beams. The light intensity was linearly proportional to the delivered dose, which is similar to that of conventional beams. No significant dose-rate dependency was observed for 0.03-837 Gy s-1. The light-intensity profiles of the UHDR beams agreed with those of conventional beams. The results did not differ between accelerators (synchrotron or cyclotron) and beam energies.Significance. Luminescence imaging of water is achievable with UHDR proton beams as well as with conventional beams. The proposed method should be suitable for rapid and easy quality assurance investigations for proton FLASH therapy, because it facilitates real-time, filmless measurements of dose distributions, and is useful for rapid feedback.

    DOI PubMed

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  • Refinement of the High-Energy Gamma-ray Selection for CALET on the International Space Station

    Nicholas W Cannady, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

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  • Statistical analysis into the drivers behind relativistic electron precipitation events observed by CALET on the International Space Station

    Anthony Ficklin, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

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  • Status of the operations of CALET for 7.5 years on the International Space Station

    Tadahisa Tamura, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

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  • Observational Challenges on the ISS: A Case Study with CALET

    Nicholas W Cannady, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

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  • Event-by-Event Analysis for TeV Electron Candidates with CALET on the International Space Station

    Nicholas W Cannady, Yosui Akaike, Shoji Torii, Oscar Adriani, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

    DOI

  • Boron flux in cosmic rays and its flux ratio to primary species measured with CALET on the International Space Station

    Paolo Maestro, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

    DOI

  • Measurement of iron cosmic-ray primaries below 10 GeV/n by use of the geomagnetic effect with CALET

    Masakatsu Ichimura, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Paolo Brogi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

    DOI

  • Helium flux and its ratio to proton flux in cosmic rays measured with CALET on the International Space Station

    Paolo Brogi, Oscar Adriani, Yosui Akaike, Katsuaki Asano, Yoichi Aaoka, Eugenio Berti, Gabriele Bigongiari, Walter Robert Binns, Massimo Bongi, Alessandro Bruno, Nicholas Wade Cannady, Guide Castellini, Caterina Checchia, Walter Robert Cherry, Gianmaria Collazuol, Georgia A. de Nolfo, Ken Ebisawa, Anthony W. Ficklin, Hideyuki Fuke, Sandro Gonzi, T. Gregory Guzik, Thomas Hams, Kinya Hibino, Masakatsu Ichimura, Kunihito Ioka, Wataru Ishizaki, Martin H. Israel, Katsumasa Kasahara, Jun Kataoka, Ryuho Kataoka, Yusaku Katayose, Chihiro Kato, Norita Kawanaka, Yuta Kawakubo, Kenko Kobayashi, Kazunori Kohri, Henric S. Krawczynski, John F. Krizmanic, Paolo Maestro, Pier Simone Marrocchesi, Alberto Maria Messineo, Jason W. Mitchell, Shoko Miyake, Alexander Moiseev, Masaki Mori, Nicola Mori, Holger Martin Motz, Kazuoki Munakata, Satoshi Nakahira, Jun Nishimura, Shoji Okuno, Jonathan Ormes, Shunsuke OZAWA, Lorenzo Pacini, Paolo Pacini, Brian Flint Rauch, Ricciarini Ricciarini, Kazuhiro Sakai, Takanori Sakamoto, Makoto Sasaki, Yuki Shimizu, Atsushi Shiomi, Piero Spillantini, Francesco Stolzi, Satoshi Sugita, Arta Sulaj, Masato Takita, Tadahisa Tamura, Toshio Terasawa, Shoji Torii, Yoshiki Tsunesada, Yukio Uchihori, Elena Vannuccini, John P. Wefel, Kazutaka Yamaoka, Shohei Yanagita, Atsumasa Yoshida, Kenji Yoshida, Wolfgang V Zober

    Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)    2023.07

    DOI

  • Citizen Science Observation of a Gamma‐Ray Glow Associated With the Initiation of a Lightning Flash

    M. Tsurumi, T. Enoto, Y. Ikkatai, T. Wu, D. Wang, T. Shinoda, K. Nakazawa, N. Tsuji, G. S. Diniz, J. Kataoka, N. Koshikawa, R. Iwashita, M. Kamogawa, T. Takagaki, S. Miyake, D. Tomioka, T. Morimoto, Y. Nakamura, H. Tsuchiya

    Geophysical Research Letters   50 ( 13 )  2023.07

    DOI

  • Simultaneous imaging of luminescence and prompt x-rays during irradiation with spot-scanning proton beams at clinical dose level.

    Seiichi Yamamoto, Tomohiro Yamashita, Yusuke Kobashi, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Biomedical physics & engineering express   9 ( 4 )  2023.06  [International journal]

     View Summary

    Prompt x-ray imaging is a promising method for observing the beam shape from outside a subject. However, its distribution is different from dose distribution, and thus a comparison with the dose is required. Meanwhile, luminescence imaging of water is a possible method for imaging the dose distribution. Consequently, we performed simultaneous imaging of luminescence and prompt x-rays during irradiation by proton beams to compare the distributions between these two different imaging methods. Optical imaging of water was conducted with spot-scanning proton beams at clinical dose level during irradiation to a fluorescein (FS) water phantom set in a black box. Prompt x-ray imaging was also conducted simultaneously from outside the black box using a developed x-ray camera during proton beam irradiation to the phantom. We measured images of the luminescence of FS water and prompt x-rays for various types of proton beams, including pencil beams, spread-out Bragg peak (SOBP) beams, and clinically used therapy beams. After the imaging, ranges were estimated from FS water and prompt x-rays and compared with those calculated with a treatment planning system (TPS). We could measure the prompt x-ray and FS water images simultaneously for all types of proton beams. The ranges estimated from the FS water and those calculated with the TPS closely matched, within a difference of several mm. Similar range difference was found between the results estimated from prompt x-ray images and those calculated with the TPS. We confirmed that the simultaneous imaging of luminescence and prompt x-rays were possible during irradiation with spot-scanning proton beams at a clinical dose level. This method can be applied to range estimation as well as comparison with the dose for prompt x-ray imaging or other imaging methods used in therapy with various types of proton beams at a clinical dose level.

    DOI PubMed

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  • A high-resolution real-time imaging system for observing the trajectories of neutron induced particles in a scintillator

    Seiichi Yamamoto, Masao Yoshino, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   18 ( 06 ) T06009 - T06009  2023.06

     View Summary

    Abstract

    High-resolution imaging of neutron induced particles is required in such methods as neutron radiography. However, the scintillation spots in a neutron-sensitive scintillator have not yet been imaged nor measured for size. We developed a high-resolution, real-time neutron induced particle imaging system for observing these particles' trajectories in a scintillator. The developed system is based on a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera combined with a lithium-containing silver-doped zinc sulfide (Li-ZnS(Ag)) scintillator plate. Neutrons from a californium-252 (252Cf) source were irradiated to the Li-ZnS(Ag) scintillator and imaged with the system. Using our system, we measured the scintillation spots of the neutron induced particles having different shapes in real time. In some of these measured scintillation spots, those with elliptical shapes were observed due to the trajectories of the particles in the scintillator. The spatial resolution calculated from the widths of the scintillation spots was ∼56 μm. Consequently, the developed imaging system is promising for research on neutron imaging that requires high spatial resolution.

    DOI

  • Hybrid imaging of prompt x-rays and induced positrons using a pinhole gamma camera during and after irradiation of protons.

    Seiichi Yamamoto, Hiroshi Watabe, Kohei Nakanishi, Takuya Yabe, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Md Rafiqul Islam, Masayasu Miyake, Kazuo S Tanaka, Jun Kataoka

    Physics in medicine and biology   68 ( 11 )  2023.05  [International journal]

     View Summary

    Objective. Prompt x-ray imaging using a low-energy x-ray camera is a promising method for observing a proton beam's shape from outside the subject. Furthermore, imaging of positrons produced by nuclear reactions with protons is a possible method for observing the beam shape. However, it has not been possible to measure these two types of images with a single imaging system due to the limited imaging capability of existing systems. Imaging of both prompt x-rays and the distribution of positrons may compensate for the shortcomings of each method.Approach. We conducted imaging of the prompt x-ray using a pinhole x-ray camera during irradiation with protons in list mode. Then, after irradiation with protons, imaging of annihilation radiations from the produced positrons was conducted using the same pinhole x-ray camera in list mode. After this imaging, list-mode data were sorted to obtain prompt x-ray images and positron images.Main results. With the proposed procedure, we could measure both prompt x-ray images and induced positron images with a single irradiation by a proton beam. From the prompt x-ray images, ranges and widths of the proton beams could be estimated. The distributions of positrons were slightly wider than those of the prompt x-rays. From the time sequential positron images, we could derive the time activity curves of the produced positrons.Significance. Hybrid imaging of prompt x-rays and induced positrons using a pinhole x-ray camera was achieved. The proposed procedure would be useful for measuring prompt x-ray images during irradiation to estimate the beam structures as well as for measuring the induced positron images after irradiation to estimate the distributions and time activity curves of the induced positrons.

    DOI PubMed

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  • Charge-Sign Dependent Cosmic-Ray Modulation Observed with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   130 ( 21 )  2023.05

    DOI

  • Direct Measurement of the Cosmic-Ray Helium Spectrum from 40 GeV to 250 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   130 ( 17 )  2023.04

    DOI

  • Development of an ultrahigh resolution real time alpha particle imaging system for observing the trajectories of alpha particles in a scintillator

    Seiichi Yamamoto, Masao Yoshino, Kei Kamada, Ryuga Yajima, Akira Yoshikawa, Kohei Nakanishi, Jun Kataoka

    Scientific Reports   13 ( 1 )  2023.04  [Refereed]

     View Summary

    Abstract

    High-resolution imaging of alpha particles is required in the detection of alpha radionuclides in cells or small organs for the development of radio-compounds for targeted alpha-particle therapy or other purposes. We developed an ultrahigh resolution, real time alpha-particle imaging system for observing the trajectories of alpha particles in a scintillator. The developed system is based on a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera, combined with a 100-µm-thick Ce-doped Gd3Al2Ga3O12 (GAGG) scintillator plate. Alpha particles from an Am-241 source were irradiated to the GAGG scintillator and imaged with the system. Using our system, we measured the trajectories of the alpha particles having different shapes in real time. In some of these measured trajectories, the line shapes of the alpha particles that flew in the GAGG scintillator were clearly observed. The lateral profiles of the alpha-particle trajectories were imaged with widths of ~ 2 µm. We conclude that the developed imaging system is promising for research on targeted alpha-particle therapy or other alpha particle detections that require high spatial resolution.

    DOI

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    6
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  • Prompt X-ray imaging during irradiation with spread-out Bragg peak (SOBP) beams of carbon ions.

    Seiichi Yamamoto, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)   109   102592 - 102592  2023.04  [International journal]

     View Summary

    Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, such imaging has so far been conducted only for pencil beams without a multi-leaf collimator (MLC). The use of spread-out Bragg peak (SOBP) with an MLC may increase the scattered prompt gamma photons and decrease the contrast of the images of prompt X-rays. Consequently, we performed prompt X-ray imaging of SOBP beams formed with an MLC. This imaging was carried out in list mode during irradiation of SOBP beams to a water phantom. An X-ray camera with a 1.5-mm diameter as well as 4-mm-diameter pinhole collimators was used for the imaging. List mode data were sorted to obtain the SOBP beam images as well as energy spectra and time count rate curves. Due to the high background counts from the scattered prompt gamma photons penetrating the tungsten shield of the X-ray camera, the SOBP beam shapes were difficult to observe with a 1.5-mm-diameter pinhole collimator. With the 4-mm-diameter pinhole collimators, images of SOBP beam shapes at clinical dose levels could be obtained with the X-ray camera. The use of a 4-mm-diameter pinhole collimator attached to the X-ray camera is effective for prompt X-ray imaging with high sensitivity and low background counts. This approach makes it possible to image SOBP beams with an MLC when the counts are low and the background levels are high.

    DOI PubMed

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    3
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  • Development of a list-mode data acquisition system for prompt X-ray imaging during irradiation with carbon-ions

    Seiichi Yamamoto, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   18 ( 4 )  2023.04

     View Summary

    Prompt X-ray imaging using a low-energy X-ray camera is a promising method for observing the beam shape from outside the subject. However, such imaging has so far been conducted only on static images with relatively long acquisition times without any energy information. Consequently, we performed list-mode prompt X-ray imaging using a newly developed data acquisition system combined with a pinhole YAP(Ce) camera during irradiation of a water phantom with carbon ions. Prompt X-ray imaging was conducted in list mode with a 1-ms time stamp and 128-channel energy bins during irradiation of a water phantom with 241.5 MeV/n carbon ions. After the imaging, list-mode data were sorted to obtain the time-sequential prompt X-ray images and those with different energies. From the images with different energies, we found the energy spectra were different depending on the areas in the images, and the reduction of the background fraction was possible. From the short time-sequential prompt X-ray images, we could even observe the differences in the images depending on the acquisition times, as well as the spill and ripple shapes of the carbon ion beam.

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  • Initial results of in vivo CT imaging of contrast agents using MPPC-based photon-counting CT

    Daichi Sato, Makoto Arimoto, Kotaro Yoshiura, Tomoya Mizuno, Ko Aiga, Kairi Ishiguro, Takahiro Tomoda, Hiroki Kawashima, Satoshi Kobayashi, Kenichiro Okumura, Kazuhiro Murakami, Jun Kataoka, Takaya Toyoda, Mayu Sagisaka, Shinsuke Terazawa, Satoshi Shiota

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1048   167960 - 167960  2023.03

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    8
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  • Development and x-ray imaging performance of Tb-doped GdAlO<inf>3</inf>- α Al<inf>2</inf>O<inf>3</inf>submicron-diameter phase-separated scintillator fibers

    M. Yoshino, K. Kamada, S. Yamamoto, R. Yajima, R. Sasaki, M. Sagisaka, J. Kataoka, T. Horiai, Y. Yokota, A. Yoshikawa

    AIP Advances   13 ( 2 )  2023.02

     View Summary

    Scintillators are key components in high-energy x-ray detectors for x-ray computed tomography, which are applied in medical diagnosis, nondestructive testing, and security inspection. Scintillators in x-ray imaging are required to have both high spatial resolution and sensitivity; however, a trade-off between spatial resolution and sensitivity exists. To improve the sensitivity of a scintillator, its thickness must be increased; however, spatial resolution deteriorates with increasing thickness. Here, we developed a well-aligned Tb-doped GdAlO3-αAl2O3 phase-separated scintillator fiber (PSSF) with a diameter of 1.25-μm by a micro-pulling-down method. The luminescence, scintillation, and imaging performances of a grown PSSF sample were evaluated. X-ray-induced radioluminescence measurements of the sample showed Tb3+ 4f-4f emissions in the wavelength range of 470-700 nm, and the maximum emission peak was at 550 nm. The contrast transfer function at 10 lp/mm was 82% for both 270 and 500 μm-thick PSSF samples. We calculated the luminescence index, which is the product of the scintillator's light yield and sensitivity, of the samples and compared their values with commercially available conventional CsI:Tl columnar scintillators. The Tb-doped GdAlO3-αAl2O3 PSSF exhibits higher contrast transfer function and luminescence index values at above 60 keV x-ray region compared with the tested conventional scintillators.

    DOI

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    9
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  • Development of 64-channel LSI with ultrafast analog and digital signal processing dedicated for photon-counting computed tomography with multi-pixel photon counter

    Makoto Arimoto, Daichi Sato, Tomoya Mizuno, Kotaro Yoshiura, Kairi Ishiguro, Takahiro Tomoda, Hiroki Kawashima, Satoshi Kobayashi, Jun Kataoka, Mayu Sagisaka, Hirokazu Ikeda, Shinsuke Terazawa, Satoshi Shiota

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1047  2023.02

     View Summary

    X-ray computed tomography (CT) is non destructive visualization inside the human body. Recently, X-ray photon-counting CT (PC-CT) has drawn attention for reducing the high doses used for patients and acquiring spectral information to identify materials. To enable photon-counting imaging with a wide region (∼60 mm long) of a small animal, we developed a photon-counting system using a 64-channel multi-pixel photon counter (MPPC) array with a fast temporal response (a few nanoseconds) and a very large signal gain (∼106), combined with a 64-channel yttrium–gadolinium–aluminum–gallium garnet scintillator array. In particular, to realize ultra-fast analog and digital signal processing (>10 MHz/channel), we developed a 64-channel large-scale integrated circuit (LSI) named MPPC-CT64. We had previously developed a 16-channel PC-CT system with a 16-channel LSI (MPPC-CT16). Although the MPPC-CT16 realized photon-counting imaging for a ∼16-mm-long phantom, there were some energy uncertainties in the LSI, which degraded the obtained CT image quality. The MPPC-CT64 implements a function for correcting the threshold energies and also increases the number of energy thresholds from four to six, which provides more precise measurements of CT values dependent on X-ray energy. In this paper, we briefly present the electric architecture and performance evaluation of the LSI combined with MPPCs.

    DOI

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    6
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  • Development of an MPPC-based gamma-ray detector onboard a radiation source imager under high-dose environments and initial performance results

    Tomoya Mizuno, Makoto Arimoto, Daichi Sato, Kotaro Yoshiura, Takahiro Tomoda, Kairi Ishiguro, Jun Kataoka, Tatsuya Sawano, Daisuke Yonetoku, Shinsuke Terazawa, Satoshi Shiota

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1046  2023.01

     View Summary

    Since the accident at the Fukushima Daiichi Nuclear Power Plant ∼10 years ago, various studies have been conducted focusing on the decontamination of radioactive materials and the decommissioning of the remains of the reactor. It is crucial to identify the locations of radioactive materials for the decontamination of a building that is exposed to high radiation doses. One of the most widely used methods is the visualization of gamma rays with energy information using a photon-counting imager. However, the existing imagers have limited functionality, making it difficult to implement them in such an environment. Therefore, we have developed a novel pinhole gamma imager containing multi-pixel photon counters (MPPCs) combined with fast scintillators, which are processed using fast signal-processing analog and digital large integrated circuits under high-dose environments. The two-dimensional sensor array developed in this study can obtain incident gamma-ray photon energies with a counting rate of a few MHz/mm2. Furthermore, we were able to perform two-dimensional gamma-ray imaging of an extremely strong radiation source of 60Co with ∼45 TBq, by combining the sensor array with the dedicated tungsten collimator and housing.

    DOI

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    4
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  • Experimental verification of efficacy of pBCT in terms of physical and biological aspects

    Mana Hosobuchi, Jun Kataoka, Hiromu Yokokawa, You Okazaki, Ryoichi Hirayama, Taku Inaniwa, Masashi Ueda, Mitsuhiro Kimura

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1045   167537  2023.01  [Refereed]

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    5
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  • Activation imaging: New concept of visualizing drug distribution with wide-band X-ray and gamma-ray imager

    N. Koshikawa, A. Omata, M. Masubuchi, J. Kataoka, Y. Kadonaga, K. Tokoi, S. Nakagawa, A. Imada, A. Toyoshima, K. Matsunaga, H. Kato, Y. Wakabayashi, T. Kobayashi, K. Takamiya, M. Ueda

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1045   167599  2023.01  [Refereed]

    DOI

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    2
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  • Experiment of in vivo imaging with third generation setup using Photon-Counting CT with 64ch Multi-Pixel Photon Counter

    M. Sagisaka, T. Toyoda, J. Kataoka, M. Arimoto, H. Kawashima, S. Kobayashi, K. Murakami, K. Okumura, D. Sato, K. Yoshiura, T. Mizuno, K. Aiga, S. Terazawa, S. Shiota

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1045  2023.01

     View Summary

    X-ray computed tomography is one of the commonly used diagnostic imaging technique. However, it has some problems which are lack of energy information and high dose exposure. These problems can be solved by using a next generation CT called Photon Counting CT (PC-CT). PC-CT can acquire multi-color images with significantly low radiation dose. The detector system of the PC-CT we propose consists of Multi-Pixel Photon Counter (MPPC) coupled with a high-speed scintillator thus can be made with lower cost and simpler system. In this study, we propose a novel method of material decomposition using the MPPC based PC-CT. Furthermore, we imaged mice with MPPC based PC-CT system as a first attempt. Iodine and gadolinium mixed contrast agents and gold-nanoparticles (AuNPs) were injected when imaging. In addition, the CT images of mice showed bone, lungs, heart, kidneys, and bladder. As a future prospect, we will work on visualizing the pharmacokinetics in mice.

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  • High-precision time study of gamma-ray bursts during thunderstorms

    E. Kuriyama, M. Masubuchi, N. Koshikawa, R. Iwashita, A. Omata, T. Kanda, J. Kataoka, M. Tsurumi, G. Diniz, T. Enoto, Y. Wada

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1045   167515 - 167515  2023.01

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  • Cosmic-ray Boron Flux Measured from 8.4 GeV/n to 3.8 TeV/n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   129 ( 25 )  2022.12  [Refereed]

     View Summary

    We present the measurement of the energy dependence of the boron flux in cosmic rays and its ratio to the carbon flux in an energy interval from 8.4 GeV/n to 3.8 TeV/n based on the data collected by the Calorimetric Electron Telescope (CALET) during ∼6.4 yr of operation on the International Space Station. An update of the energy spectrum of carbon is also presented with an increase in statistics over our previous measurement. The observed boron flux shows a spectral hardening at the same transition energy E0∼200 GeV/n of the C spectrum, though B and C fluxes have different energy dependences. The spectral index of the B spectrum is found to be γ=-3.047±0.024 in the interval 25<E<200 GeV/n. The B spectrum hardens by ΔγB=0.25±0.12, while the best fit value for the spectral variation of C is ΔγC=0.19±0.03. The B/C flux ratio is compatible with a hardening of 0.09±0.05, though a single power-law energy dependence cannot be ruled out given the current statistical uncertainties. A break in the B/C ratio energy dependence would support the recent AMS-02 observations that secondary cosmic rays exhibit a stronger hardening than primary ones. We also perform a fit to the B/C ratio with a leaky-box model of the cosmic-ray propagation in the Galaxy in order to probe a possible residual value λ0 of the mean escape path length λ at high energy. We find that our B/C data are compatible with a nonzero value of λ0, which can be interpreted as the column density of matter that cosmic rays cross within the acceleration region.

    DOI PubMed

  • Short time sequential luminescence imaging of water during irradiation by protons

    Seiichi Yamamoto, Takuya Yabe, Katsunori Yogo, Takashi Akagi, Jun Kataoka

    Journal of Instrumentation   17 ( 12 )  2022.12

     View Summary

    <jats:title>Abstract</jats:title>
    <jats:p>Although luminescence imaging of water during irradiation by particle ions is a promising method for dose estimation, it has only been tried for static images in which temporal information is not included. In addition to the positional distribution of the beam, temporal information is also important because the beams from a synchrotron-based therapy system have short pulse shapes called spills. The temporal information is also important for high dose rate, short-time radiotherapy, or so-called FLASH radiotherapy. To measure the particle ion beam distributions with precise temporal information, we conducted short time sequential luminescence imaging of protons. First, we measured short time sequential luminescence images during irradiation of a water phantom by 150-MeV protons using a cooled charge-coupled device (CCD) camera at 0.143-s intervals. With this imaging, the images showed beam distributions, but the shapes of the spill were not precisely evaluated in time intensity curves due to the insufficient sampling rate of the imaging. Then we measured short time sequential optical images with 0.053-s intervals. With this imaging, the images showed that the beam distributions in the spill shape could be measured, but the image and depth profiles evaluated from the images were noisy due to the insufficient light intensity. Consequently, we measured short time sequential luminescence images during irradiation of fluorescein (FS) water by 150-MeV protons. Since FS water produced ∼10 times higher luminescence, we could obtain high-intensity images enabling us to evaluate the time intensity curves based on the shape of the spills during measurement with 0.053-s intervals. The depth profiles of the beam were also obtained from the measured images. With these results, we confirmed that time sequential luminescence imaging was possible and, in such cases, FS water images measured at 0.053-s intervals are most promising to measure the short time sequential luminescence images during irradiation of protons.</jats:p>

    DOI

  • Multi-modal 3D imaging of radionuclides using multiple hybrid Compton cameras

    Akihisa Omata, Miho Masubuchi, Nanase Koshikawa, Jun Kataoka, Hiroki Kato, Atsushi Toyoshima, Takahiro Teramoto, Kazuhiro Ooe, Yuwei Liu, Keiko Matsunaga, Takashi Kamiya, Tadashi Watabe, Eku Shimosegawa, Jun Hatazawa

    Scientific Reports   12 ( 1 )  2022.12

     View Summary

    <title>Abstract</title>For radiological diagnosis and radionuclide therapy, X-ray and gamma-ray imaging technologies are essential. Single-photon emission tomography (SPECT) and positron emission tomography (PET) play essential roles in radiological diagnosis, such as the early detection of tumors. Radionuclide therapy is also rapidly developing with the use of these modalities. Nevertheless, a limited number of radioactive tracers are imaged owing to the limitations of the imaging devices. In a previous study, we developed a hybrid Compton camera that conducts simultaneous Compton and pinhole imaging within a single system. In this study, we developed a system that simultaneously realizes three modalities: Compton, pinhole, and PET imaging in 3D space using multiple hybrid Compton cameras. We achieved the simultaneous imaging of Cs-137 (Compton mode targeting 662 keV), Na-22 (PET mode targeting 511 keV), and Am-241 (pinhole mode targeting 60 keV) within the same field of view. In addition, the imaging of Ga-67 and In-111, which are used in various diagnostic scenarios, was conducted. We also verified that the 3D distribution of the At-211 tracer inside a mouse could be imaged using the pinhole mode.

    DOI

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  • Activation imaging of drugs with hybrid Compton camera: A proof-of-concept study

    N. Koshikawa, A. Omata, M. Masubuchi, Y. Okazaki, J. Kataoka, K. Matsunaga, H. Kato, A. Toyoshima, Y. Wakabayashi, T. Kobayashi

    Applied Physics Letters   121 ( 19 ) 193701 - 193701  2022.11  [Refereed]

     View Summary

    The visualization of drugs is essential for cancer treatment. Although several methods for visualizing drugs have been proposed, a versatile method that can be easily applied to various drugs has not yet been established. Therefore, we propose “activation imaging,” in which a drug is irradiated with thermal neutrons and becomes radioactive, enabling visualization using emitted x rays and/or gamma rays. Activation imaging does not require the conjugation of specific tracers with drugs. Therefore, it can be easily applied to a variety of drugs, drug carriers (e.g., metal nanoparticles), and contrast agents. In this study, neutron activation, gamma-ray spectroscopy, and imaging of drug carriers, anticancer drug, and contrast agents were performed. Gold nanoparticles (AuNPs) and platinum nanoparticles were used as drug carriers, cisplatin was used as an anticancer drug, and gadoteridol and iohexol were used as contrast agents. As a neutron source, the RIKEN accelerator-driven compact neutron source II (RANS-II) was utilized. The imaging was performed using a hybrid Compton camera (HCC). The HCC can visualize x rays and gamma rays ranging from a few keV to nearly 1 MeV, which enables the imaging of various x rays and gamma rays emitted from the activated drugs. As a result, the gamma-ray spectra indicated the generation of radioisotopes through neutron irradiation, and AuNPs and iohexol were visualized.

    DOI

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    5
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  • Optimization of the energy window setting in Ir-192 source imaging for high-dose-rate brachytherapy using a YAP(Ce) gamma camera

    Jura Nagata, Kohei Nakanishi, Seiichi Yamamoto, Takuya Yabe, Katsunori Yogo, Yumiko Noguchi, Kuniyasu Okudaira, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Physica Medica   103   66 - 73  2022.11

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    3
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  • Compton Camera Imaging of a Gamma-Ray Glow From a Thunderstorm

    E. Kuriyama, M. Masubuchi, N. Koshikawa, R. Iwashita, A. Omata, T. Kanda, J. Kataoka, M. Tsurumi, G. Diniz, T. Enoto, Y. Wada

    Geophysical Research Letters   49 ( 19 )  2022.10

     View Summary

    Gamma-ray glows associated with thunderclouds have been observed since the 1980s, however it remains unclear how, and at which thunderstorms gamma-ray glows are generated in dense atmospheres. In this study, we report the first Compton camera imaging of a gamma-ray glow from a winter thundercloud. On 14 January 2022, using two identical Bi4Ge3O12 scintillators in energy range of 0.05–5 MeV, we detected two gamma-ray glows lasting ∼4 min in a mountain area 25 km from the Japan Sea and 410 m above sea level. The same events were also observed by the Compton camera, where the first glow we observed suggested statistically significant (4.0 and 5.9 σ level) signals of two enhanced concentrations in gamma-ray photon images in a range of 0.15–1.5 MeV. These concentrations were most clearly observed in a time window of Δt = 50 s around the peak intensity of the gamma-ray glow.

    DOI

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    3
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  • Wide-band X-ray and gamma-ray imaging of living mouse to reveal pharmacokinetics of At-211

    M. Masubuchi, A. Omata, N. Koshikawa, J. Kataoka, H. Kato, A. Toyoshima, K. Ooe, D. Katayama, T. Teramoto, K. Matsunaga, T. Kamiya, T. Watabe, E. Shimosegawa, J. Hatazawa

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment     167581 - 167581  2022.10

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    4
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  • Monte Carlo approach to comparison of parallel-hole collimators of clinical scintillation camera system for imaging astatine-211 (At-211)

    Kohei Nakanishi, Seiichi Yamamoto, Jun Kataoka

    Journal of Instrumentation   17 ( 10 ) T10007 - T10007  2022.10

     View Summary

    Abstract

    Astatine-211 (At-211) is a promising alpha particle emitter for targeted radionuclide therapy. Since its daughter isotope (polonium-211(Po-211)) emits characteristic X-rays of about 80 keV, the distribution of At-211 in the body can be imaged by detecting the X-rays with a scintillation camera. However, the isotopes also emit high-energy gamma photons that are collimated with difficulty for a parallel-hole collimator of a clinical scintillation camera system, and thus the selection of a collimator is important. In this study, we compared the performances of low-energy high-resolution (LEHR), low-energy all-purpose (LEAP), medium-energy (ME), and high-energy (HE) parallel-hole collimators for At-211 using Monte Carlo simulation. We simulated a clinical scintillation camera system with the collimators using the Geant4 toolkit. The energy spectra, sensitivities, and spatial resolutions for the point source of At-211 were evaluated. Moreover, we simulated imaging of six sphere sources of At-211 in a 1-cm-thick cylindrical phantom filled with At-211 solution to evaluate image contrast. All of the results in this study are simulation data. The spatial resolution with LEHR was 7.6 mm full width at half maximum (FWHM) and the highest between collimators, while the sensitivity with LEAP was 85 cps/MBq and the highest. The image contrast acquired with the ME collimator was superior to those with the other collimators. We concluded that the LEHR, LEAP, and ME collimators had their advantages, so an optimum collimator should be selected depending on the purpose of imaging of At-211, although there was no advantage in using the HE collimator for the imaging of At-211.

    DOI

  • Performance demonstration of a novel photon-counting CT for preclinical application

    T. Toyoda, J. Kataoka, M. Sagisaka, M. Arimoto, D. Sato, K. Yoshiura, H. Kawashima, S. Kobayashi, J. Kotoku, S. Terazawa, S. Shiota, M. Ueda

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   1040  2022.10

     View Summary

    Photon-counting computed tomography (PC-CT) has attracted attention over the last few years as the next-generation CT technique that solves the problems encountered in clinical CT. In PC-CT, dark current and electronic noise can be reduced by setting the energy threshold to exceed the noise level, which leads to a low-dose scan. Furthermore, multiple energy thresholds realize multicolor CT imaging, which is not possible with clinical CT. Recently, we proposed a novel PC-CT system consisting of a multipixel photon counter (MPPC) coupled with a high-speed scintillator, performing simultaneous imaging of multiple contrast agents and estimate concentration. However, the PC-CT images obtained by our PC-CT system faces some limitations, such as degradation of image quality due to the lack of photon statistics and/or image resolution loss due to the pixel size of the detectors. In this study, the signal-to-noise ratio (SNR) of the PC-CT images was improved by applying machine-learning models, that is, U-Net and Noise2Noise, to the PC-CT images. In addition, a new imaging method was developed to acquire the high-resolution CT images required for clinical use. As a result, the resolution of the CT images improved from 1.04 mm to 0.77 mm. Finally, the visualization of contrast agents in plants was set as a challenge for the next step towards the clinical application of MPPC-based PC-CT. The results demonstrate that our PC-CT system can provide color imaging not only in phantom-based experiments, but also in plants close to an organism.

    DOI

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    2
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  • Short‐time sequential high‐energy gamma photon imaging using list‐mode data acquisition system for high‐dose‐rate brachytherapy

    Jura Nagata, Seiichi Yamamoto, Takuya Yabe, Katsunori Yogo, Kohei Nakanishi, Yumiko Noguchi, Kuniyasu Okudaira, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Medical Physics    2022.09

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  • A high-resolution X-ray microscope system for performance evaluation of scintillator plates

    Seiichi Yamamoto, Masao Yoshino, Kei Kamada, Ryuga Yajima, Akira Yoshikawa, Mayu Sagisaka, Jun Kataoka

    JOURNAL OF INSTRUMENTATION   17 ( 9 )  2022.09

     View Summary

    In the development of new scintillators for X-ray imaging, a high-resolution and highly efficient system is required to evaluate the performance of the scintillator plates. For this purpose, we developed a high-resolution X-ray microscope system. The developed compact X-ray microscope system is based on a magnifying unit and a cooled charge-coupled device (CCD) camera, combined with a small industrial X-ray irradiation system. Using this system, we carried out imaging of three scintillator plates and evaluated their spatial resolution. Each scintillator plates was set in front of the lens of the objective, X-rays were irradiated to the scintillator plates, and transmission images of masks were acquired. The measured spatial resolution of the scintillator plates varied from 16 mu m to 30 mu m, depending on the type of scintillator plate. The focus size of the X-ray tube had an almost negligible effect on the spatial resolution of the images for the evaluated scintillator plates.

    DOI

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    5
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  • Advantages of using larger-diameter pinhole collimator for prompt X-ray imaging during irradiation with carbon ions

    Seiichi Yamamoto, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Journal of Instrumentation   17 ( 9 )  2022.09

     View Summary

    Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, the images measured within short times suffer from statistical noise. Consequently, we performed prompt X-ray imaging with higher sensitivity using a larger-diameter pinhole collimator and compared the results with those of a conventional collimator. Prompt X-ray imaging was conducted during irradiation with pencil beams of 241.5-MeV/n carbon ions to a water phantom. A newly developed X-ray camera with a 4-mm diameter as well as conventional 1.5-mm-diameter pinhole collimators was used for the imaging in list mode, and we compared the prompt X-ray images, energy spectra, and time count rate curves between 1.5-mm-diameter and 4-mm-diameter pinhole collimators. The prompt X-ray images taken with the 4-mm-diameter pinhole collimators had a1/47 times higher sensitivity with 70 % lower offset fractions originating from the prompt gamma photons. Furthermore, the ranges were more precisely estimated with the 4-mm collimator than with the 1.5-mm collimator. The energy spectra showed less contamination by tungsten-characteristic X-rays for the 4-mm pinhole collimator. Even for images measured with 0.1-s intervals, the beam shapes and time count rate curves could be obtained with less statistical noise using the 4-mm-diameter pinhole collimators. The use of the 4-mm-diameter pinhole collimator attached to the X-ray camera had advantages for prompt X-ray imaging with high sensitivity and low background, enabling us to image the beams even with short-Time measurements.

    DOI

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    3
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  • Observation of Spectral Structures in the Flux of Cosmic-Ray Protons from 50 GeV to 60 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   129 ( 10 )  2022.09

    DOI

  • Technical note: Correcting angular dependencies using non‐polarized components of Cherenkov light in water during high‐energy X‐ray irradiation

    Chihiro Toyonaga, Seiichi Yamamoto, Takuya Yabe, Kuniyasu Okudaira, Katsunori Yogo, Yoshiyuki Hirano, Jun Kataoka

    Medical Physics   49 ( 8 ) 5409 - 5416  2022.08  [Refereed]

    DOI

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  • Development of a capillary plate based fiber-structured ZnS(Ag) scintillator

    Seiichi Yamamoto, Kei Kamada, Masao Yoshino, Akira Yoshikawa, Naoki Sunaguchi, Jun Kataoka

    JOURNAL OF INSTRUMENTATION   17 ( 8 )  2022.08

     View Summary

    Silver-doped zinc sulfide (ZnS(Ag)) is an opaque powder scintillator that is mainly used for detection or imaging of charged particles such as alpha particles. Since ZnS(Ag) is not transparent, the thickness of ZnS(Ag) was limited to -10 mu m. If a thicker ZnS(Ag) scintillator could be developed, it would be useful for studies such as high-energy particle ion detection as well as beta particle or gamma photon detection. We developed a ZnS(Ag) fiber-structured scintillator using a capillary plate in which ZnS(Ag) powder was encapsulated in the capillaries. The thickness of the capillary plate was 400 mu m, and the light produced in ZnS(Ag) escaped from the capillaries, spread through the transparent lead glass area, and reached the opposite side of the plate; consequently, the opaque character and absorption of light could be avoided. The amount of light emitted from the capillary plate based fiber-structured ZnS(Ag) was almost the same as that of a commercially available ZnS (Ag) film, but the detection efficiency was about 1/5 (-20%). The amount of light emitted from beta particles and gamma photons per MeV was less than 1% of that from alpha particles. The spatial resolution of the developed capillary plate based fiber-structured ZnS(Ag) scintillator for 5.5 MeV alpha particles was -200 mu m FWHM. Imaging of the slits and light spots from alpha particles could be achieved with the developed scintillator combined with an electron-multiplied charge-coupled device (EM-CCD) camera. The developed capillary plate based fiber-structured ZnS(Ag) will be useful for detecting high-energy particle ions.

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  • CALET Search for Electromagnetic Counterparts of Gravitational Waves during the LIGO/Virgo O3 Run

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    The Astrophysical Journal   933 ( 1 ) 85 - 85  2022.07

     View Summary

    Abstract

    The CALorimetric Electron Telescope (CALET) on the International Space Station consists of a high-energy cosmic-ray CALorimeter (CAL) and a lower-energy CALET Gamma-ray Burst Monitor (CGBM). CAL is sensitive to electrons up to 20 TeV, cosmic-ray nuclei from Z = 1 through Z ∼ 40, and gamma rays over the range 1 GeV–10 TeV. CGBM observes gamma rays from 7 keV to 20 MeV. The combined CAL-CGBM instrument has conducted a search for gamma-ray bursts (GRBs) since 2015 October. We report here on the results of a search for X-ray/gamma-ray counterparts to gravitational-wave events reported during the LIGO/Virgo observing run O3. No events have been detected that pass all acceptance criteria. We describe the components, performance, and triggering algorithms of the CGBM—the two Hard X-ray Monitors consisting of LaBr3(Ce) scintillators sensitive to 7 keV–1 MeV gamma rays and a Soft Gamma-ray Monitor BGO scintillator sensitive to 40 keV–20 MeV—and the high-energy CAL consisting of a charge detection module, imaging calorimeter, and the fully active total absorption calorimeter. The analysis procedure is described and upper limits to the time-averaged fluxes are presented.

    DOI

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  • Trials of transmission imaging using clinically used Ir-192 source for high-dose-rate brachytherapy

    J. Nagata, S. Yamamoto, K. Nakanishi, Y. Noguchi, K. Okudaira, J. Kataoka

    Journal of Instrumentation   17 ( 06 ) T06009 - T06009  2022.06  [Refereed]

     View Summary

    Abstract

    In high-dose-rate (HDR) brachytherapy, verification of an Ir-192 source's position during treatment is required. One of the methods for this used a high-energy pinhole gamma camera to image the position of the source, but the absolute position of the source cannot be measured. To confirm the absolute position, it will be useful to acquire the transmission image of a subject in addition to the gamma photon image at the same time without using an additional X-ray system. To measure the transmission images, we tried to use the high-energy gamma photons emitted from the Ir-192 source used for the therapy. We developed a high-energy gamma photon imaging system composed of 1-mm-thick Pr doped Gd2O2S (GOS), a surface mirror, and a cooled charge-coupled device (CCD) camera. The developed imaging system achieved transmission imaging of high-energy gamma photons by transporting the Ir-192 source in front of the imaging system. The spatial resolution of the imaging system was better than 2.4 mm FWHM with and without a 10-cm-thick acrylic block set between the imaging system and the source. Moderate spatial resolution and contrast images of phantoms were obtained with the system. For the dynamic imaging mode, continuous images of the phantoms were measured with 1-sec intervals. There was no observable difference in the transmission images by the movement of the Ir-192 source. Transmission imaging of subjects using an Ir-192 source for HDR brachytherapy could be achieved using our developed imaging system. The system offers a new method to measure the real-time transmission images of the subject during HDR brachytherapy.

    DOI

  • CALET on the International Space Station: a precise measurement of the iron spectrum

    O. Adriani, Yosui Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, Caterina Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, Francesco Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Proceedings of Science   398  2022.05

     View Summary

    The Calorimetric Electron Telescope (CALET) was launched on the International Space Station in 2015 and since then has collected a large sample of cosmic-ray charged particles over a wide energy. Thanks to a couple of layers of segmented plastic scintillators placed on top of the detector, the instrument is able to identify the charge of individual elements from proton to iron (and above). The imaging tungsten scintillating fiber calorimeter provides accurate particle tracking and the lead tungstate homogeneous calorimeter can measured the energy with a wide dynamic range. One of the CALET scientific objectives is to measure the energy spectra of cosmic rays to shed light on their acceleration and propagation in the Galaxy. By the observation in first five years, a precise measurement of the iron spectrum is now available in the range of kinetic energy per nucleon from 10 GeV/n to 2 TeV/n. The CALET's result with a description of the analysis and details on systematic uncertainties will be illustrated. Also, a comparison with previous experiments' results is given.

  • Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8 GeV/ n to 240 GeV/ n with CALET on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   128 ( 13 )  2022.04

     View Summary

    The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other transiron elements; therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than ∼3 GeV/n are available at present in the literature, and they are affected by strong limitations in both energy reach and statistics. In this Letter, we present a measurement of the differential energy spectrum of nickel in the energy range from 8.8 to 240 GeV/n, carried out with unprecedented precision by the Calorimetric Electron Telescope (CALET) in operation on the International Space Station since 2015. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The particle's energy is measured by a homogeneous calorimeter (1.2 proton interaction lengths, 27 radiation lengths) preceded by a thin imaging section (3 radiation lengths) providing tracking and energy sampling. This Letter follows our previous measurement of the iron spectrum [1O. Adriani (CALET Collaboration), Phys. Rev. Lett. 126, 241101 (2021).PRLTAO0031-900710.1103/PhysRevLett.126.241101], and it extends our investigation on the energy dependence of the spectral index of heavy elements. It reports the analysis of nickel data collected from November 2015 to May 2021 and a detailed assessment of the systematic uncertainties. In the region from 20 to 240 GeV/n our present data are compatible within the errors with a single power law with spectral index -2.51±0.07.

    DOI PubMed

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  • Interaction of the galactic-centre super bubbles with the gaseous disc

    Yoshiaki Sofue, Jun Kataoka

    Monthly Notices of the Royal Astronomical Society   506 ( 2 ) 2170 - 2180  2021.09

     View Summary

    The interaction of Galactic centre (GC) super bubbles (GSBs) with the gaseous disc and halo of the Milky Way is investigated using radio continuum, X-ray, H i, and CO line surveys. The radio North Polar Spur (NPS) constitutes the brightest eastern ridge of GSB, brightening towards the galactic plane and reaching l = 22°, b = +2° at the sharpest end, where it intersects the tangential direction of the 3-kpc-expanding ring and crater. Examination of the spur ridges reveals that the entire GSB, including the NPS and its counter spurs, constitutes a GC-symmetrical ω/ω shape. The thickness and gas density of the H i and CO discs are shown to increase sharply from the inside (lower longitude) to the outside the 3-kpc crater. Formation of crater is explained by the sweeping of the upper layer of disc gas by the shock wave from the GC by the explosion ~10 My ago with the emitted energy of several 1055 erg. Based on the discussion, a unified view on the structure and formation mechanism of GSB is presented.

    DOI

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  • Spatial Variations of Magnetic Field along Active Galactic Nuclei Jets on Sub-parsec to Megaparsec Scales

    S. Ito, Y. Inoue, J. Kataoka

    Astrophysical Journal   916 ( 2 )  2021.08

     View Summary

    We report the systematic analysis of knots, hotspots, and lobes in 57 active galactic nuclei (AGNs) to investigate the variation of the magnetic field along the jet from the sub-parsec base to the terminus on kiloparsec-to-megaparsec scales. Expanding the number of radio/X-ray samples in the work of Kataoka & Stawarz, we analyzed the data in 12 FR i and 30 FR ii radio galaxies, 12 quasars, and three BL Lac objects, which contained 76 knots, 42 hotspots, and 29 radio lobes. We first derived the equipartition magnetic fields in the cores and then estimated those in various jet components by assuming B est ∝ d -1, where d is the distance from the jet base. On the other hand, the magnetic field in large-scale jets (knots, hotspots, and lobes), B eq, can be estimated from the observed flux and spatial extent under the equipartition hypothesis. We show that the magnetic field decreases as the distance along the jet increases, but generally in a more gentle way than ∝d -1. The increase in B eq/B est at large d may suggest the deceleration of the jet downstream, but there is no difference between FR i and FR ii jets. Moreover, the magnetic fields in the hotspots are systematically larger than those in knots and lobes. Finally, we applied the same analysis to knots and lobes in Centaurus A to check whether the above discussion will hold even in a single jet source.

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    4
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  • Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV/n to 2.0 TeV/n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   126 ( 24 )  2021.06

     View Summary

    The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray iron over a wide energy interval. In this Letter a measurement of the iron spectrum is presented in the range of kinetic energy per nucleon from 10 GeV/n to 2.0 TeV/n allowing the inclusion of iron in the list of elements studied with unprecedented precision by space-borne instruments. The measurement is based on observations carried out from January 2016 to May 2020. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The energy is measured by a homogeneous calorimeter with a total equivalent thickness of 1.2 proton interaction lengths preceded by a thin (3 radiation lengths) imaging section providing tracking and energy sampling. The analysis of the data and the detailed assessment of systematic uncertainties are described and results are compared with the findings of previous experiments. The observed differential spectrum is consistent within the errors with previous experiments. In the region from 50 GeV/n to 2 TeV/n our present data are compatible with a single power law with spectral index -2.60±0.03.

    DOI PubMed

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  • Machine-learning Application to Fermi-LAT Data: Sharpening All-sky Map and Emphasizing Variable Sources

    Shogo Sato, Jun Kataoka, Soichiro Ito, Jun'Ichi Kotoku, Masato Taki, Asuka Oyama, Takaya Toyoda, Yuki Nakamura, Marino Yamamoto

    Astrophysical Journal   913 ( 2 )  2021.06

     View Summary

    A novel application of machine-learning (ML) based image processing algorithms is proposed to analyze an all-sky map (ASM) obtained using the Fermi Gamma-ray Space Telescope. An attempt was made to simulate a 1 yr ASM from a short-exposure ASM generated from 1-week observation by applying three ML-based image processing algorithms: dictionary learning, U-net, and Noise2Noise. Although the inference based on ML is less clear compared to standard likelihood analysis, the quality of the ASM was generally improved. In particular, the complicated diffuse emission associated with the galactic plane was successfully reproduced only from 1-week observation data to mimic a ground truth (GT) generated from a 1 yr observation. Such ML algorithms can be implemented relatively easily to provide sharper images without various assumptions of emission models. In contrast, large deviations between simulated ML maps and the GT map were found, which are attributed to the significant temporal variability of blazar-type active galactic nuclei (AGNs) over a year. Thus, the proposed ML methods are viable not only to improve the image quality of an ASM but also to detect variable sources, such as AGNs, algorithmically, i.e., without human bias. Moreover, we argue that this approach is widely applicable to ASMs obtained by various other missions; thus, it has the potential to examine giant structures and transient events, both of which are rarely found in pointing observations.

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  • Development of a neutron camera system to visualize the dose distribution by secondary neutrons for safer proton therapy

    R. Tanaka, J. Kataoka, F. Nishi, H. Yokokawa, T. Inaniwa

    Journal of Instrumentation   16 ( 6 )  2021.06

     View Summary

    Proton therapy has recently garnered significant attention as an effective treatment for cancer that can effectively damage tumor tissues while reducing doses to healthy tissues and organs. However, secondary neutrons generated by interactions with protons and brass collimators or the patient's body may cause harm to the human body. Nevertheless, the risks are yet to be precisely assessed or reflected in actual treatment plans. In this study, we develop a novel neutron camera that enables the visualization of spatial dose distribution by secondary neutrons. First, a neutron camera comprising two layers of units is constructed; each of the layer is composed of a plastic scintillator coupled with a photomultiplier tube. As a preliminary experiment, it is confirmed that the developed camera can visualize fission neutrons from a 252Cf source. Subsequently, secondary neutrons are observed from a brass (imitating the brass collimator) and water (imitating the patient's body) phantom irradiated with a 70 MeV proton beam, in which the neutron camera is placed at 0°, 15° (only in the case of brass) and 30° from each phantom 30 cm ahead. Following neutron/gamma event selections using two methods, i.e., time of flight and pulse shape discrimination, each of the reconstructed images successfully converged at the correct positions, with average angular resolutions of 21° (brass, full width at half maximum (FWHM)) and 19° (water, FWHM). Furthermore, dosimetry using the G(E) function method is applied to the images, enabling a dose distribution image to be created using secondary neutrons. As a result, the evaluated dose rate is 307 μSv/min for brass and 88.1 μSv/min for water, which are 86 % and 64 % those of the simulated dose rates, respectively. Eventually, future tasks for the utilization of the camera in actual proton therapy are discussed.

    DOI

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    2
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  • Application of machine-learning models to improve the image quality of photon-counting CT images

    T. Toyoda, S. Sato, H. Kiji, J. Kataoka, J. Kotoku, M. Taki

    Journal of Instrumentation   16 ( 5 )  2021.05

     View Summary

    X-ray computed tomography (CT) has been widely used in medical diagnostic imaging. However, conventional, energy-integrated CT requires a high radiation dose and can only provide monochromatic images that cannot eliminate various artifacts. In contrast, photon-counting CT (PC-CT) provides low-dose multicolor CT imaging, which enables the identification of multiple contrast agents. However, in the PC-CT system, the lack of photon statistics, which is also caused by image reconstruction in the limited energy band, severely affects the image quality. In this study, we applied three types of machine-learning (ML) techniques to improved the image quality of PC-CT, that is, dictionary learning, U-Net, and Noise2Noise. These ML models were trained using low- and high-dose image pairs created in simple steps. The trained ML models were applied to simulated data, and experimental PC-CT images of contrast agents used in clinical practice. Consequently, in the simulated data, the peak signal-to-noise ratio (PSNR) value improved from 21.3 for the input to 26.6, 33.3, and 30.1 for dictionary learning, U-Net, and Noise2Noise, respectively. Furthermore, in the actual PC-CT images, we successfully reproduced PC-CT images with high PSNR, which enabled simultaneous imaging of multiple contrast agents with improved accuracy of concentration estimation. As a future perspective, we will develop a processing technique that can be applied to in vivo CT images.

    DOI

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    2
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  • Demonstration of low-concentration nanoparticle imaging for integrated treatment-diagnostic spectral CT

    Dima Sonia Djara, Kiji Hiroaki, Toyoda Takaya, Kataoka Jun, Arimoto Makoto, Sato Daichi, Yoshiura Kotaro, Kawashima Hiroki, Kobayashi Satoshi, Terazawa Shinsuke, Shiota Satoshi, Ikeda Hirokazu

    JSAP Annual Meetings Extended Abstracts   2021.1   492 - 492  2021.02

    DOI

  • Performance Evaluation of Multi-Channel Imaging using MPPC-based Spectral Photon-Counting CT

    Sato Daichi, Arimoto Makoto, Yoshiura Kotaro, Mizuno Tomoya, Kawashima Hiroki, Kobayashi Satoshi, Kataoka Jun, Kiji Hiroaki, Toyoda Takaya, Dima Sonia, Ikeda Hirokazu, Terazawa Shinsuke, Shiota Satoshi

    JSAP Annual Meetings Extended Abstracts   2021.1   491 - 491  2021.02

    DOI

  • Origin of galactic spurs: New insight from radio/X-ray all-sky maps

    Jun Kataoka, Marino Yamamoto, Yuki Nakamura, Soichiro Ito, Yoshiaki Sofue, Yoshiyuki Inoue, Takeshi Nakamori, Tomonori Totani

    Astrophysical Journal   908 ( 1 )  2021.02

     View Summary

    In this study, we analyze giant Galactic spurs seen in both radio and X-ray all-sky maps to reveal their origins. We discuss two types of giant spurs: one is the brightest diffuse emission near the map's center, which is likely to be related to Fermi bubbles (NPSs/SPSs, north/south polar spurs, respectively), and the other is weaker spurs that coincide positionally with local spiral arms in our Galaxy (LAS, Local Arm spur). Our analysis finds that the X-ray emissions, not only from the NPS but also from the SPS, are closer to the Galactic center by ~5° compared with the corresponding radio emission. Furthermore, larger offsets of 10°-20° are observed in the LASs; however, they are attributed to different physical origins. Moreover, the temperature of the X-ray emission is kT ≃ 0.2 keV for the LAS, which is systematically lower than those of the NPS and SPS (kT ≃ 0.3 keV) but consistent with the typical temperature of Galactic halo gas. We argue that the radio/X-ray offset and the slightly higher temperature of the NPS/SPS X-ray gas are due to the shock compression/heating of halo gas during a significant Galactic explosion in the past, whereas the enhanced X-ray emission from the LAS may be due to the weak condensation of halo gas in the arm potential or star formation activity without shock heating.

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  • Performance Estimate of MPPC-based PC-CT System and Initial Results of CT Image Contrast

    D. Sato, M. Arimoto, K. Yoshiura, T. Mizuno, K. Aiga, H. Kawashima, S. Kobayashi, J. Kataoka, T. Toyoda, M. Sagisaka, H. Ikeda, S. Terazawa, S. Shiota

    2021 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2021 and 28th International Symposium on Room-Temperature Semiconductor Detectors, RTSD 2022    2021

     View Summary

    X-ray computed tomography (CT) is widely used for three-dimensional nondestructive X-ray imaging of the internal structure of the human body or industrial materials. For modern technology in the medical field, dual-energy CT (DE-CT) with two types of X-ray effective energy has generally been used. However, the X-ray signals of DE-CT are integrated and read out in the form of a current. Thus, contamination with dark noise significantly degrades such imaging qualities as contrast, which causes a large radiation dose to patients. In addition, little energy information on DE-CT results in poor material discrimination of target materials. Recently, the photon-counting CT (PC-CT) system has developed for future CT technology. Because the PC-CT system can detect individual X-ray photons, the dark-noise effect expected to be highly suppressed. The multiple energy data obtained by PC-CT provide fruitful information on the energy dependence of the CT values, leading to high potential for material discrimination. Thus, an MPPC-based PC-CT system combined with high-speed scintillators has been proposed, and a 64-channel CT array system was developed recently. In this study, the details of the performance estimate of the MPPC-based PC-CT system were investigated in terms of energy information and photon-counting capability. The initial results of the CT image contrast compared with the clinical DE-CT system are presented. They show that the proposed PC-CT system achieved a similar contrast-to-noise ratio value to that of the clinical DE-CT.

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  • 64-channel photon-counting computed tomography using a new MPPC-CT system

    H. Kiji, T. Maruhashi, T. Toyoda, J. Kataoka, M. Arimoto, D. Sato, K. Yoshiura, S. Kobayashi, H. Kawashima, S. Terazawa, S. Shiota, H. Ikeda

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   984  2020.12

     View Summary

    X-ray computed tomography (CT) is a widely used diagnostic tool to visualize the interior of the human body. However, the exposure dose of conventional CT in a single scan is large, typically 10 mSv, and therefore, it is necessary to find ways to reduce the radiation dose. Furthermore, conventional CT does not contain the energy information of individual X-ray photons because the X-ray signals are read out as an integrated form. This causes misidentification of materials. To resolve this issue, we propose a novel photon counting CT (PC-CT) system consisting of multi-pixel photon counters (MPPCs) coupled with high speed scintillators. The system has a 64-channel MPPC array that improves energy information and wide-area imaging. By fine energy adjustment and increasing the number of energy thresholds to six, which were newly implemented in the 64-channel PC-CT system, we succeeded in accurately estimating the concentrations of contrast agents such as iodine and gadolinium. Moreover, for mixed phantoms of iodine and gadolinium, we demonstrate discrimination between them, and estimate the concentrations individually, which cannot be done by conventional CTs. This shows great potential in expanding the applications of X-ray CTs.

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    16
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  • Direct Measurement of the Cosmic-Ray Carbon and Oxygen Spectra from 10 GeV/ n to 2.2 TeV/ n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   125 ( 25 )  2020.12

     View Summary

    In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10 GeV/n to 2.2 TeV/n with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index change of ∼0.15 around 200 GeV/n established with a significance >3σ. They have the same energy dependence with a constant C/O flux ratio 0.911±0.006 above 25 GeV/n. The spectral hardening is consistent with that measured by AMS-02, but the absolute normalization of the flux is about 27% lower, though in agreement with observations from previous experiments including the PAMELA spectrometer and the calorimetric balloon-borne experiment CREAM.

    DOI PubMed

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  • Performance demonstration of a hybrid Compton camera with an active pinhole for wide-band X-ray and gamma-ray imaging

    Akihisa Omata, Jun Kataoka, Kazuya Fujieda, Shogo Sato, Eri Kuriyama, Hiroki Kato, Atsushi Toyoshima, Takahiro Teramoto, Kazuhiro Ooe, Yuwei Liu, Keiko Matsunaga, Takashi Kamiya, Tadashi Watabe, Eku Shimosegawa, Jun Hatazawa

    Scientific Reports   10 ( 1 )  2020.12

     View Summary

    X-ray and gamma-ray imaging are technologies with several applications in nuclear medicine, homeland security, and high-energy astrophysics. However, it is generally difficult to realize simultaneous wide-band imaging ranging from a few tens of keV to MeV because different interactions between photons and the detector material occur, depending on the photon energies. For instance, photoabsorption occurs below 100 keV, whereas Compton scattering dominates above a few hundreds of keV. Moreover, radioactive sources generally emit both X-ray and gamma-ray photons. In this study, we develop a “hybrid” Compton camera that can simultaneously achieve X-ray and gamma-ray imaging by combining features of “Compton” and “pinhole” cameras in a single detector system. Similar to conventional Compton cameras, the detector consists of two layers of scintillator arrays with the forward layer acting as a scatterer for high-energy photons (> 200 keV) and an active pinhole for low-energy photons (< 200 keV). The experimental results on the performance of the hybrid camera were consistent with those from the Geant4 simulation. We simultaneously imaged 241Am (60 keV) and 137Cs (662 keV) in the same field of view, achieving an angular resolution of 10∘ (FWHM) for both sources. In addition, imaging of 211At was conducted for the application in future nuclear medicine, particularly radionuclide therapy. The initial demonstrative images of the 211At phantom were reconstructed using the pinhole mode (using 79 keV) and Compton mode (using 570 keV), exhibiting significant similarities in source-position localization. We also verified that a mouse injected with 1 MBq of 211At can be imaged via pinhole-mode measurement in an hour.

    DOI PubMed

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  • Precision spectroscopy of cesium-137 from the ground to 150 m above in Fukushima

    Takuya Kurihara, Kazuhisa Tanada, Jun Kataoka, Hiroki Hosokoshi, Saku Mochizuki, Leo Tagawa, Hiroshi Okochi, Yurie Gotoh

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   978  2020.10

     View Summary

    After the Fukushima nuclear disaster in 2011, large amounts of radioisotopes (mainly 137Cs and 134Cs) were released into the environment. Various monitoring activities have revealed radiation on the ground both in local and wide areas; however, aerial dose variation in the vertical direction is poorly known. This paper presents the results of airborne gamma-ray spectroscopy of a contamination field in Namie, Fukushima, as measured from 0 m to 150 m above the ground by drone. We found that the gamma-ray dose rate measured at 100 m height is about seven times higher than that expected based on ground measurements, which is caused by two factors: (1) the integrated dose includes contamination of upward scattered 662-keV gamma rays and (2) radiation from 137Cs is vertically collimated because 137Cs is buried in the soil. We also propose a novel method to obtain the distribution of radioactive substances in the soil only through aerial mapping.

    DOI

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    2
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  • High-statistics image generation from sparse radiation images by four types of machine-learning models

    S. Sato, J. Kataoka, J. Kotoku, M. Taki, A. Oyama, L. Tagawa, K. Fujieda, F. Nishi, T. Toyoda

    Journal of Instrumentation   15 ( 10 )  2020.10

     View Summary

    With the development of nuclear medicine diagnostics and treatment, the demand for image processing techniques has been increasing. Although single photon emission computed tomography (SPECT) and positron emission tomography (PET) are most common, the energy ranges they permit for imaging are limited to either below 300 keV (SPECT) or to 511 keV gamma rays (PET). Recently, Compton cameras have attracted attention, owing to their wide energy range, which stretches from a few hundred keV to several MeV. In this study, we performed Compton camera image processing using four machine-learning (ML) techniques: dictionary learning, UNet, SRGAN, and AUTOMAP. With these techniques, we tried to reduce the artifacts caused by the sparsity of statistics and improve the signal-to-noise ratio (SNR). Thus, these ML models were trained using image pairs reconstructed from high- and low-statistics images. As a result, we succeeded in generating images similar to the ground truth from low-statistics images. We argue that this technique can be applied not only to Compton camera images but also to other radiation imaging devices. As a future perspective, we mention the possibility of applying our imaging and processing technique to in vivo imaging of alpha-particle internal therapy.

    DOI

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  • Origin of the in-orbit instrumental background of the Hard X-ray Imager onboard Hitomi

    Kouichi Hagino, Hirokazu Odaka, Goro Sato, Tamotsu Sato, Hiromasa Suzuki, Tsunefumi Mizuno, Madoka Kawaharada, Masanori Ohno, Kazuhiro Nakazawa, Shogo B. Kobayashi, Hiroaki Murakami, Katsuma Miyake, Makoto Asai, Tatsumi Koi, Greg Madejski, Shinya Saito, Dennis H. Wright, Teruaki Enoto, Yasushi Fukazawa, Katsuhiro Hayashi, Jun Kataoka, Junichiro Katsuta, Motohide Kokubun, Philippe Laurent, François Lebrun, Olivier Limousin, Daniel Maier, Kazuo Makishima, Kunishiro Mori, Takeshi Nakamori, Toshio Nakano, Hirofumi Noda, Masayuki Ohta, Rie Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin'Ichiro Takeda, Takaaki Tanaka, Yukikatsu Terada, Hideki Uchiyama, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Yoichi Yatsu, Takayuki Yuasa

    Journal of Astronomical Telescopes, Instruments, and Systems   6 ( 4 )  2020.10

     View Summary

    Understanding and reducing in-orbit instrumental backgrounds are essential to achieving high sensitivity in hard x-ray astronomical observations. The observational data of the Hard X-ray Imager (HXI) onboard the Hitomi satellite provide useful information on the background components due to its multilayer configuration with different atomic numbers: The HXI consists of a stack of four layers of Si (Z = 14) detectors and one layer of cadmium telluride (CdTe) (Z = 48, 52) detector surrounded by well-Type Bi4Ge3O12 active shields. Based on the observational data, the backgrounds of the top Si layer, the three underlying Si layers, and the CdTe layer are inferred to be dominated by different components, namely, low-energy electrons, albedo neutrons, and proton-induced radioactivation, respectively. Monte Carlo simulations of the in-orbit background of the HXI reproduce the observed background spectrum of each layer well, thereby quantitatively verifying the above hypothesis. In addition, we suggest the inclusion of an electron shield to reduce the background.

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  • First application of the super-resolution imaging technique using a Compton camera

    S. Sato, J. Kataoka, J. Kotoku, M. Taki, A. Oyama, L. Tagawa, K. Fujieda, F. Nishi, T. Toyoda

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   969  2020.07  [Refereed]

     View Summary

    © 2020 Elsevier B.V. In medical imaging, precise and reliable images are very important. However, the quality of medical images is sometimes limited by low-event statistics owing to the low sensitivity of the detectors commonly used in radiology. On the other hand, long exposure to radiation and long inspection duration can become a burden for patients. In this paper, we propose a method for generating high-quality images of gamma ray sources from low statistic data by using machine learning methods based on dictionary learning and sparse coding. As the first application, we generated a high-quality image of 137Cs, which emits 662-keV gamma rays, from low-event statistics measured using a Compton camera. We simulated with Geant4 various geometries of the gamma-ray source (137Cs; 662 keV) as measured with a Compton camera by Geant4. Then, complete sets of low-resolution and high-resolution dictionaries were prepared. We generated super-resolution images from low-resolution test images obtained from actual measurements. The convergence of the gamma-ray images was similar for both the ground truth and predicted images, as supported by the improvements in the structural similarity (SSIM), peak signal-to-noise (PSNR) ratio, and root mean square error (RMSE) in the corresponding images. We also discuss future plans to use the super-resolution technique for visualizing radium chloride (223RaCl2) in the patient's body, which will make it possible to achieve in-vivo imaging of alpha-particle internal therapy for the first time.

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  • CALET on the International Space Station: The first three years of observations

    P. Brogi, P. Brogi, O. Adriani, O. Adriani, Y. Akaike, Y. Akaike, K. Asano, Y. Asaoka, Y. Asaoka, M. G. Bagliesi, M. G. Bagliesi, E. Berti, E. Berti, G. Bigongiari, G. Bigongiari, W. R. Binns, S. Bonechi, S. Bonechi, M. Bongi, M. Bongi, A. Bruno, J. H. Buckley, N. Cannady, N. Cannady, G. Castellini, C. Checchia, C. Checchia, M. L. Cherry, G. Collazuol, G. Collazuol, V. Di Felice, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. F. Krizmanic, J. Link, J. Link, P. Maestro, P. Maestro, P. S. Marrocchesi, P. S. Marrocchesi, A. M. Messineo, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, F. Palma, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, S. B. Ricciarini, K. Sakai, K. Sakai, T. Sakamoto, M. Sasaki, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, F. Stolzi, S. Sugita, J. E. Suh, J. E. Suh, A. Sulaj

    Physica Scripta   95 ( 7 )  2020.07

     View Summary

    The CALorimetric Electron Telescope CALET is a space instrument designed to carry out precision measurements of high energy cosmic-rays on the JEM-EF external platform on the International Space Station, where it has been collecting science data continuously since mid October 2015. In addition to its primary goal of identifying nearby sources of high-energy electrons and possible signatures of dark matter in the electron spectrum, CALET is carrying out extensive measurements of the energy spectra, relative abundances and secondary-to-primary ratios of elements from proton to iron, and even above (up to Z = 40), studying the details of galactic particle propagation and acceleration. An overview of CALET based on the data taken during the first three years of observations is presented, including a direct measurement of the electron+positron energy spectrum from 11 GeV to 4.8 TeV. The proton spectrum has been measured from 50 GeV to 10 TeV covering, for the first time with a single space-borne instrument, the whole energy interval previously investigated in separate sub-ranges by magnetic spectrometers and calorimetric instruments. Preliminary spectra of cosmic-ray nuclei are also presented, together with gamma-ray observations and searches for an e.m. counterpart of LIGO/Virgo GW events.

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  • Development of Gamma-Ray Detector Arrays Consisting of Diced Eu-Doped SrI<inf>2</inf>Scintillator Arrays and TSV-MPPC Arrays

    M. Yoshino, M. Yoshino, K. Kamada, K. Kamada, Y. Shoji, Y. Yokota, S. Kurosawa, A. Yamaji, Y. Ohashi, H. Sato, K. Fujieda, J. Kataoka, A. Yoshikawa, A. Yoshikawa, A. Yoshikawa

    IEEE Transactions on Nuclear Science   67 ( 6 ) 999 - 1002  2020.06  [Refereed]

     View Summary

    © 1963-2012 IEEE. This article presents the development of diced SrI2:Eu arrays and their scintillation properties when coupled with a multipixel photon counter (MPPC) array. Using a dicing technique specific to halide scintillators, a high-energy resolution scintillator array is developed that is cost-effective and widely applicable. The developed SrI2:Eu arrays are of 3 × 3 × 3 mm3/pixel 4 × 4 matrix (TYPE1) and 1 × 1 × 1 mm3/pixel 9 × 9 matrix (TYPE2) structures. We fabricated test gamma-ray detector modules consisting of the TYPE1 and TYPE2 arrays coupled with an MPPC array. The mean peak to valleys ratio is 85.3 ± 14.9 for the TYPE1 array and 38.5 ± 16.6 for the TYPE2 array detector. The average energy resolutions obtained for the TYPE1 and TYPE2 gamma-ray detectors were 5.4 ± 0.4% full-width at half-maximum (FWHM) and 5.2 ± 0.6% FWHM, respectively, for 662-keV gamma-rays. The variation in the signal pulse height of the TYPE1 and TYPE2 detectors was only 10.6% and 10.4% in FWHM, respectively. These results demonstrated that the dicing technique proposed in this article could be applied to hygroscopic halide scintillators.

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  • Demonstration of multiple contrast agent imaging for the next generation color X-ray CT

    T. Maruhashi, H. Kiji, T. Toyoda, J. Kataoka, M. Arimoto, S. Kobayashi, H. Kawashima, S. Terazawa, S. Shiota, H. Ikeda

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   958  2020.04  [Refereed]

     View Summary

    © 2019 Elsevier B.V. X-ray computed tomography (CT) is widely used for non-invasive diagnostic imaging of the inside of the human body. It should be noted that the approximate effective radiation dose in a patient is 10 mSv. Under such an environment, X-ray photons are severely piled-up. Therefore, conventional CT only reconstructs energy integrated image, which may consist of beam hardening artifacts that have proven to be a problem. In contrast, photon counting CT (PC-CT) offers a low-dose multicolor CT imaging. The PC-CT also enables K-edge imaging that can improve the blood–tissue contrast using specific contrast agents. Moreover, the PC-CT has great advantages in (1) the simultaneous imaging of multiple contrast agents, and (2) the absolute quantification of contrast agents. Owing to these advantages, the PC-CT system can provide more detailed tissue diagnosis than conventional CT systems. Recently, we proposed a novel PC-CT system (Morita et al., 2017; Arimoto et al., 2017, Maruhashi et al., 2018) consisting of multipixel photon counter (MPPC) coupled with a high-speed scintillator, which is a cost-effective and easy to assemble system, as compared to other PC-CT devices based on cadmium zinc telluride. In this paper, we operated the K-edge imaging of specific contrast agents using a 16-channel MPPC PC-CT system. Our PC-CT system established appropriate energy thresholds and operated the simultaneous imaging of multiple contrast agents such as iodine and gadolinium. In addition, we estimated the absolute concentration of these contrast agents. The results show that our PC-CT system can provide more accurate diagnostic medical imaging, as compared to the conventional CT system.

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  • CALET results after three years on the International Space Station

    Y. Asaoka, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, N. Opsina, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, V. Pal'Shin, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, I. Takahashi, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Journal of Physics: Conference Series   1468 ( 1 )  2020.03

     View Summary

    The CALET (CALorimetric Electron Telescope) space experiment, which is currently conducting direct cosmic-ray observations onboard the International Space Station (ISS), is an all-calorimetric instrument optimized for cosmic-ray electron measurements with capability to measure hadrons and gamma-rays. Since the start of observation in October 2015, smooth and continuous operations have taken place. In this paper, we will give a brief summary of the CALET observations ranging from charged cosmic rays, gamma-rays, to space weather, while focusing on the energy spectra of electrons and protons.

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  • Development and evaluation of 64-ch fast LSI using MPPCs for future X-ray CT

    Sato Daichi, Arimoto Makoto, Yoshiura Kotaro, Kawashima Hiroki, Kobayashi Satoshi, Kataoka Jun, Maruhashi Takuya, Kiji Hiroaki, Toyoda Takaya, Ikeda Hirokazu, Terazawa Shinsuke, Shiota Satoshi

    JSAP Annual Meetings Extended Abstracts   2020.1   545 - 545  2020.02

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  • Performance demonstration of new 64-channnel system for next generation color X-ray CT

    Toyoda Takaya, Maruhashi Takuya, Kiji Hiroaki, Kataoka Jun, Arimoto Makoto, Sato Daichi, Yoshiura Kotaro, Kobayashi Satoshi, Kawashima Hiroki, Terazawa Shinsuke, Shiota Satoshi, Ikeda Hirokazu

    JSAP Annual Meetings Extended Abstracts   2020.1   546 - 546  2020.02

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  • Beta-ray imaging system with γ-ray coincidence for multiple-tracer imaging

    Tomonori Fukuchi, Seiichi Yamamoto, Jun Kataoka, Kei Kamada, Akira Yoshikawa, Yasuyoshi Watanabe, Shuichi Enomoto

    Medical Physics   47 ( 2 ) 587 - 596  2020.02  [Refereed]  [International journal]

     View Summary

    PURPOSE: Beta-ray imaging systems are widely used for various biological objects to obtain a two-dimensional (2D) distribution of β-ray emitting radioisotopes. However, a conventional β-ray imaging system is unsuitable for multiple-tracer imaging, because the continuous energy distribution of β-rays complicates distinguishing among different tracers by energy information. Therefore, we developed a new type of β-ray imaging system, which is useful for multiple tracers by detecting coincidence γ-rays with β-rays, and evaluated its imaging performance. METHODS: Our system is composed of position-sensitive β-ray and γ-ray detectors. The former is a 35 × 35 × 1-mm3 Ce-Doped((La, Gd)2 Si2 O7 ) (La-GPS) scintillation detector, which has a 300-µm pitch of pixels. The latter is a 43 × 43 × 16-mm3 bismuth germanium oxide (BGO) scintillation detector. Both detectors are mounted on a flexible frame and placed in a user-selectable position. We experimentally evaluated the performance of the β-ray detector and the γ-ray efficiencies of the γ-ray detector with different energies, positions, and distances. We also conducted point sources and phantom measurements with dual isotopes to evaluate the system performance of multiple-tracer imaging. RESULTS: For the β-ray detector, the β-ray detection efficiencies for 45 Ca (245-keV maximum energy) and 90 Sr/90 Y (545 and 2280-keV maximum energy) were 14.3% and 21.9%, respectively. The total γ-ray detection efficiency of the γ-ray detector for all γ-rays from 22 Na (511-keV annihilation γ-rays and a 1275-keV γ-ray) in the center position with a detector distance of 20 mm was 17.5%. From a point-source measurement using 22 Na and 90 Sr/90 Y, we successfully extracted the position of a positron-γ emitter 22 Na. Furthermore, for a phantom experiment using 45 Ca and 18 F or 18 F and 22 Na, we successfully extracted the distribution of the second tracer using the annihilation γ-ray or de-excitation γ-ray coincidence. In all the imaging experiments, the event counts of the extracted images were consistent with the counts estimated by the measured γ-ray efficiencies. CONCLUSIONS: We successfully demonstrated the feasibility of our β-ray autoradiography system for imaging multiple isotopes. Since our system can identify not only a β-γ emitter but also a positron emitter using the coincidence detection of annihilation γ-rays, it is useful for PET tracers and various new applications that are otherwise impractical.

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  • First demonstration of portable Compton camera to visualize 223-Ra concentration for radionuclide therapy

    K.Fujieda, J.Kataoka, S.Mochizuki, L.Tagawa, S.Sato, R.Tanaka, K.Matsunaga, T.Kamiya, T.Watabe, H.Kato, E.Shimosegawa, J.Hatazawa

    Nuclear Instruments and Methods in Physics Research Section A   in press  2019.12  [Refereed]

     View Summary

    Radionuclide therapy (RNT) is an internal radiation therapy that can selectively damage cancer cells. Recently, the use of alpha-emitting radionuclides was initiated in RNT owing to its dose concentration and short range. In particular, 223Ra is widely used for bone metastasis of prostate cancer. Despite its potential for clinical applications, it is difficult to determine whether a drug has been properly delivered to the target lesion. As such, we propose a new method of monitoring nuclear gamma rays promptly and simultaneously emitted from 223Ra as alpha decay using a high-sensitivity Compton camera. We first observed a small bottle of 223Ra solution with a total radioactivity of 0.56 MBq. The reconstructed image converged at the correct position with a position resolution of ∼20 mm at a plane 10 cm in front of the camera. Next, we observed a phantom consisting of three spheres with diameters ranging from 13 to 37 mm filled with 223Ra solution (9 kBq/mL) and then surrounded by a ∼20-cm layer of water. A three-dimensional (3D) image was constructed by rotating the Compton camera around the phantom. Images were then acquired from eight directions at 30-min intervals, respectively. Although the image resolution remained limited at 351 keV, three spheres were resolved at the correct position in the 3D image with their relative intensities. Thirdly, we observed the body of a patient for 10 min and reconstructed almost the same accumulation as the image acquired by a single-photon emission computed tomography (SPECT) system for 30 min. While the spatial resolution of the Compton camera was worse, DOI-CC obtained a wider image in a shorter time. Finally, we discuss current problems and plans for improving sensitivity and angular resolution for future clinical applications.

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  • Development and performance verification of a 3-D position-sensitive Compton camera for imaging MeV gamma rays

    H.Hosokoshi, J.Kataoka, S.Mochizuki, M.Yoneyama, S.Ito, H.Kiji, F.Nishi, S.Miyamoto, T.Shima

    Nature Scientific Reports   in press ( 1 )  2019.12  [Refereed]

     View Summary

    In gamma-ray astronomy, the 1–10 MeV range is one of the most challenging energy bands to observe owing to low photon signals and a considerable amount of background contamination. This energy band, however, comprises a substantial number of nuclear gamma-ray lines that may hold the key to understanding the nucleosynthesis at the core of stars, spatial distribution of cosmic rays, and interstellar medium. Although several studies have attempted to improve observation of this energy window, development of a detector for astronomy has not progressed since NASA launched the Compton Gamma Ray Observatory (CGRO) in 1991. In this work, we first developed a prototype 3-D position-sensitive Compton camera (3D-PSCC), and then conducted a performance verification at NewSUBARU, Hyogo in Japan. To mimic the situation of astronomical observation, we used a MeV gamma-ray beam produced by laser inverse Compton scattering. As a result, we obtained sharp peak images of incident gamma rays irradiating from incident angles of 0° and 20°. The angular resolution of the prototype 3D-PSCC was measured by the Angular Resolution Measure and estimated to be 3.4° ± 0.1° (full width at half maximum (FWHM)) at 1.7 MeV and 4.0° ± 0.5° (FWHM) at 3.9 MeV. Subsequently, we conceived a new geometry of the 3D-PSCC optimized for future astronomical observations, assuming a 50-kg class small satellite mission. The SΩ of the 3D-PSCC is 11 cm2sr, anticipated at 1 MeV, which is small but provides an interesting possibility to observe bright gamma-ray sources owing to the high intrinsic efficiency and large field of view (FoV).

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  • Linking advanced medicine and space through gamma-ray imaging; Challenges for a palm-sized Compton camera

    Jun Kataoka

    Applied Physics   88 ( 11 ) 730 - 734  2019.11  [Refereed]  [Invited]

    DOI

  • Stable Radio Core of the Blazar Mrk 501 during High-energy Active State in 2012

    Shoko Koyama, Motoki Kino, Akihiro Doi, Kotaro Niinuma, Marcello Giroletti, David Paneque, Kazunori Akiyama, Gabriele Giovannini, Guang-Yao Zhao, Eduardo Ros, Jun Kataoka, Monica Orienti, Kazuhiro Hada, Hiroshi Nagai, Naoki Isobe, Hideyuki Kobayashi, Mareki Honma, Rocco Lico

    The Astrophysical Journal   884 ( 2 ) 132  2019.10  [Refereed]

     View Summary

    We investigate the precise location of the radio core in the nearby blazar Mrk 501 for the first time during its X-ray and TeV γ-ray active state in 2012 by revisiting from the perspective of astrometry the six-epoch observations with the Very Long Baseline Array at 43 GHz reported by Koyama et al. We find that the position of the radio core seen at 43 GHz remained stable during our observations from 2012 to 2013 February within 42 μas in the southeast jet direction and 56 μas along the northeast jet direction. This implies that the location of the 43 GHz radio-emitting core was limited within the deprojected scale of 4.6 × 103 Schwarzschild radii (R s) during the high-energy active state. This result is a contrast to another case of the astrometric observation of the famous nearby TeV blazar Mrk 421, which showed a clear radio core position change soon after the large X-ray flare in 2011, reported by Niinuma et al. We compare the two cases and discuss possible origins of the different results of the radio core astrometry in the high-energy active states between the nearby blazars. Based on the internal shock model for blazars, the Lorentz factors of the ejecta explaining the stability of the radio core in Mrk 501 are expected to be a few times smaller than those for the wandering core in Mrk 421.

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  • ML-EM algorithm for dose estimation using PET in proton therapy

    Takamitsu Masuda, Teiji Nishio, Jun Kataoka, Makoto Arimoto, Akira Sano, Kumiko Karasawa

    Physics in Medicine and Biology   64 ( 17 ) 175011  2019.09  [Refereed]

     View Summary

    © 2019 Institute of Physics Publishing. All rights reserved. Positron emission tomography (PET) has been extensively studied and clinically investigated for dose verification in proton therapy. However, the production distributions of positron emitters are not proportional to the dose distribution. Thus, direct dose evaluation is limited when using the conventional PET-based approach. We propose a method for estimating the dose distribution from the positron emitter distributions using the maximum likelihood (ML) expectation maximization (EM) algorithm combined with filtering. In experiments to verify the effectiveness of the proposed method, mono-energetic and spread-out Bragg-peak proton beams were delivered by a synchrotron, and a water target was irradiated at clinical dose levels. Planar PET measurements were performed during beam pauses and after irradiation over a total period of 200 s. In addition, we conducted a Monte Carlo simulation to obtain the required filter functions and analyze the influence of the number of algorithm iterations on estimation. We successfully estimated the 2D dose distributions even under statistical noise in the PET images. The accuracy of the 2D dose estimation was about 10% for both beams at the 1-σ values of relative error. This value is comparable to the deviations in the measured PET activity distributions. For the laterally integrated profile along the beam direction, a low error within 5% was obtained per irradiation value. Moreover, the difference of estimated proton ranges was within 1 mm, and 2D estimation from the PET images was completed in 21 ms. Hence, the proposed algorithm may be applied to real-time dose monitoring. Although this is the first attempt to use the ML-EM algorithm for dose estimation, the proposed method showed high accuracy and speed in the estimation of proton dose distribution from PET data. The proposed method is thus a step forward to exploit the full potential of PET for in vivo dose verification.

    DOI PubMed

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  • Development of novel neutron camera to estimate secondary particle dose for safe proton therapy

    L. Tagawa, J. Kataoka, K. Sueoka, K. Fujieda, T. Kurihara, M. Arimoto, S. Mochizuki, T. Maruhashi, T. Toshito, M. Kimura, T. Inaniwa

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   936   31 - 33  2019.08  [Refereed]

     View Summary

    © 2018 Elsevier B.V. Proton therapy causes less damage to healthy tissue compared to other radiation therapies; however, the possible damage caused by secondary, fast neutrons is almost unknown. In some simulations, neutron dose amounts to 10% of the proton dose; therefore, a real-time visualization of the neutron dose is needed. We have developed a neutron camera that can visualize the direction and intensity of fast neutron sources. The camera consists of eight units of a plastic scintillator (EJ-299-34) coupled with a compact PMT (R9880U). We demonstrate that a 252Cf neutron source is correctly imaged with an angular resolution of 15.5 deg (FWHM). In addition, fast neutrons emitted from the brass block irradiated by 70 MeV were successfully monitored in real time. Finally, we present our prospects for future clinical applications.

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  • Evaluation of a novel photon-counting CT system using a 16-channel MPPC array for multicolor 3-D imaging

    T.Maruhashia, Morita, M.Arimoto, J.Kataoka, K.Fujieda, H.Nitta, H.Ikeda, H.Kiji

    Nuclear Instruments and Methods in Physics Research Section A   936   5 - 9  2019.08  [Refereed]

     View Summary

    X-ray computed tomography (CT) has been widely used in the diagnostic imaging of the interior of the human body. However, the radiation dose of conventional CT typically amounts to 10 mSv. Under such environments, X-ray photons are severely piled-up; therefore, conventional CT acquires energy integrated images, and artifacts are formed by beam hardening. In contrast, a photon counting CT (PC-CT) system is anticipated to construct a low-dose and multi-color CT system. Recently, we proposed a novel PC-CT system using a multipixel photon counter (MPPC) coupled with a high-speed scintillator, which is cost effective and easy to assemble compared to other methods using CdZnTe device. In this paper, we report the results using an advanced CT system consisting of a 16-channel MPPC and scintillator array coupled with a newly developed large-scale integrated circuit (LSI) having an ultrafast signal processing capability. We present the performance of the photon-counting CT capability, such as the contrast of the obtained CT images compared with that of the current-mode CT, and we found that substantial reduction in radiation dose by an order of magnitude. In addition, we report the results of three-dimensional multicolor imaging to identify phantom materials.

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  • High-precision compton imaging of 4.4 MeV prompt gamma-ray toward an on-line monitor for proton therapy

    S.Mochizuki, J.Kataoka, A.Koide, K.Fujieda, T.Maruhashi, T.Kurihara, K.Sueoka, L.Tagawa, M.Yoneyama, T.Inaniwa

    Nuclear Instruments and Methods in Physics Research Section A   936   43 - 45  2019.08  [Refereed]

     View Summary

    Proton therapy is a widely used and effective treatment for cancer. A high-dose concentration of proton beam reduces damage to normal tissues. However, it also requires a high accuracy of irradiation. PET is generally used to verify the proton range after irradiation, but, the distributions of positrons and the energy deposited by protons are not similar to each other. Recently, prompt gamma-ray imaging has attracted attention as a new, online imaging technique. In particular, 4.4 MeV gamma rays emitted from 12C* is one of the best probes to monitor the proton dose, however imaging techniques are far from established. We have developed a novel, 3-D position sensitive Compton camera based on Ce:GAGG scintillators coupled with multi-pixel photon counter (MPPC) arrays, thus making it optimized for imaging in the 1–10 MeV range. The angular resolution is 5 degrees (FWHM) at 4.4 MeV. We have established various methods to discriminate multiple-Compton and escape events, both of which can be critical backgrounds for precise imaging of prompt gamma rays. By irradiating a 70 MeV proton beam on the PMMA phantom, we demonstrated that 4.4 MeV gamma ray image is sharply concentrated on the Bragg peak, as was expected from the PHITS simulation.

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  • Inverse Compton Scattering of Starlight in the Kiloparsec-scale Jet in Centaurus A: The Origin of Excess TeV γ-Ray Emission

    K.Tanada, J, Kataoka, Y.Inoue

    The Astrophysical Journal   878 ( 2 ) 139 - 147  2019.06  [Refereed]

     View Summary

    Centaurus A (Cen A) is the nearest active radio galaxy, which has kiloparsec-scale jets and giant lobes detected by various instruments in radio and X-ray frequency ranges. The Fermi-Large Area Telescope and High Energy Stereoscopic System (HESS) confirmed that Cen A is a very high-energy (VHE; >0.1 TeV) γ-ray emitter with a known spectral softening in the energy range from a few GeV to TeV. In this work, we consider a synchrotron self-Compton model in the nucleus for the broadband spectrum below the break energy and an external Compton model in kiloparsec-scale jets for the γ-ray excess. Our results show that the observed γ-ray excess can be suitably described by the inverse Compton scattering of the starlight photons in the kiloparsec-scale jets, which is consistent with the recent tentative report by HESS on the spatial extension of the TeV emission along the jets. Considering the spectral fitting results, the excess can only be seen in Cen A, which is probably due to two factors: (1) the host galaxy is approximately 50 times more luminous than other typical radio galaxies and (2) the core γ-ray spectrum quickly decays above a few MeV due to the low maximum electron Lorentz factor of γ c = 2.8 103 resulting from the large magnetic field of 3.8 G in the core. By the comparison with other γ-ray detected radio galaxies, we found that the magnetic field strength of relativistic jets scales with the distance from the central black holes d with B(d) ∝ d -0.88 0.14.

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  • Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   122 ( 18 )  2019.05  [Refereed]

     View Summary

    © 2019 authors. In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from-2.81±0.03 (50-500 GeV) neglecting solar modulation effects (or-2.87±0.06 including solar modulation effects in the lower energy region) to-2.56±0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.

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  • Development of simple proton CT system with novel correction methods of proton scattering

    M. Takabe, T. Masuda, M. Arimoto, J. Kataoka, K. Sueoka, T. Maruhashi, S. Tanaka, T. Nishio, T. Toshito, M. Kimura, T. Inaniwa

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   924   332 - 338  2019.04  [Refereed]

     View Summary

    © 2018 For safe and effective proton therapy, the proton range in a patient's body is characterized by the water equivalent length (WEL), and must be accurately determined. Current treatment planning is based on X-ray computed tomography images, which might cause uncertainty because of the different energy loss processes between protons and X-rays. We develop a simple, novel, and real-time proton CT system. The system uses a CCD camera and scintillator, which is thin enough for protons to penetrate. Since protons lose energy when they pass through a phantom, different emissions corresponding to the proton energy loss are acquired in the scintillator. Images of the scintillator were gathered by the CCD camera with 70 MeV and 200 MeV proton beams. Since blurring due to proton reactions such as multiple Coulomb scattering and nuclear reactions significantly degrades the obtained images in both beams, we developed two kinds of effective correction methods. One method is applied to broad beam systems, while the other is applied to narrow beam systems. We successfully obtain clear images with minor proton reaction effects by applying these correction methods. Moreover, we confirm that the WEL values estimated from the acquired CT images agree well with the theoretical values for materials such as polymethyl methacrylate (PMMA) and isopropyl alcohol, within 1-σ uncertainty. Through simulations, we found that nuclear reactions significantly contribute to the uncertainty of WEL values.

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  • An ultrahigh spatial resolution radiation-imaging detector using 0.1 mm × 0.1 mm pixelated GAGG plate combined with 1 mm channel size Si-PM array

    S.Yamamoto, J.Kataoka, K.Kamada, A.Yoshikawa

    Nuclear Instruments and Methods in Physics Research, Section A   919   125 - 133  2019.03  [Refereed]

     View Summary

    Spatial resolution of a pixelated scintillator-based radiation-imaging detector is sometimes limited by the pixel size of the scintillators. We developed a small-size pixelated GAGG scintillator using a dicing method and combined it with a small channel-size Si-PM array for the development of an ultrahigh resolution radiation-imaging detector. The developed pixelated GAGG scintillator had a pixel size of 0.1 mm × 0.1 mm arranged in 0.15-mm separations. It was combined with a Si-PM array made of 1 mm × 1 mm channels to form a radiation-imaging detector. With the developed radiation imaging detectors, the 0.1 mm × 0.1 mm pixels could be resolved for Am-241 alpha particles (5.5 MeV). The spatial resolutions of this imaging detector were better than 0.31-mm FWHM for Am-241 alpha particles and Ca-45 (maximum energy: 0.257 MeV) beta particles. The spatial resolutions for Am-241 gamma photons (60 keV) and Cs-137 X-ray (∼32 keV) were better than 0.6-mm FWHM. Separation of the images of alpha particles and gamma photons was possible using the scintillation decay time difference of GAGG between alpha particles and gamma photons. The developed ultrahigh spatial resolution pixelated GAGG radiation-imaging detector is promising for the imaging of alpha particles, beta particles, low-energy gamma photons and X-ray.

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  • PoGO+ polarimetric constraint on the synchrotron jet emission of Cygnus X-1

    Maxime Chauvin, Hans Gustav Florén, Miranda Jackson, Tuneyoshi Kamae, Jun Kataoka, Mózsi Kiss, Victor Mikhalev, Tsunefumi Mizuno, Hiromitsu Takahashi, Nagomi Uchida, Mark Pearce

    Monthly Notices of the Royal Astronomical Society: Letters,   483 ( 1 ) 138 - 143  2019.02  [Refereed]

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    We report a polarimetric constraint on the hard X-ray synchrotron jet emission from the Cygnus X-1 black hole binary system. The observational data were obtained using the PoGO+ hard X-ray polarimeter in 2016 July, when Cygnus X-1 was in the hard state. We have previously reported that emission from an extended corona with a low polarization fraction is dominating, and that the polarization angle is perpendicular to the disc surface. In the soft gamma-ray regime, a highly polarized synchrotron jet is reported with INTEGRAL observations. To constrain the polarization fraction and flux of such a jet component in the hard X-ray regime, we now extend analyses through vector calculations in the Stokes QU plane, where the dominant corona emission and the jet component are considered simultaneously. The presence of another emission component with different polarization angle could partly cancel out the net polarization. The 90 per cent upper limit of the polarization fraction for the additional synchrotron jet component is estimated as <10 per cent, <5 per cent, and <5 per cent for polarization angle perpendicular to the disc surface, parallel to the surface, and aligned with the emission reported by INTEGRAL data, respectively. From the 20-180 keV total flux of 2.6 × 10 -8 erg s -1 cm -2, the upper limit of the polarized flux is estimated as < 3 × 10 -9 erg s -1 cm -2.

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  • Ultracompact Compton camera for innovative gamma-ray imaging

    J. Kataoka, A. Kishimoto, T. Taya, S. Mochizuki, L. Tagawa, A. Koide, K. Sueoka, H. Morita, T. Maruhashi, K. Fujieda, T. Kurihara, M. Arimoto, H. Okochi, N. Katsumi, S. Kinno, K. Matsunaga, H. Ikeda, E. Shimosegawa, J. Hatazawa, S. Ohsuka, T. Toshito, M. Kimura, Y. Nagao, M. Yamaguchi, K. Kurita, N. Kawachi

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   912   1 - 5  2018.12  [Refereed]

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    © 2017 Elsevier B.V. A multipixel photon counter (MPPC) features excellent photon-counting capability as a radiation detector. In particular, a two-plane Compton camera consisting of Ce:GAGG scintillators coupled with MPPC arrays has significant application potential owing to its compact size and low weight. For example, the camera can be easily mounted on a commercial drone to identify radiation hot spots from the sky. In Fukushima, we demonstrated that a 137Cs distribution within a 100 m diameter can be mapped correctly within a couple of tens of minutes. The advanced use of the Compton camera is also anticipated in the field of proton therapy. We evaluated an image of 511 keV annihilation gamma-rays emitted from a PMMA phantom irradiated by 200 MeV protons to mimic an in-beam monitor for proton therapy. Finally, we developed an ultracompact Compton camera (weight = 580 g), for 3-D multicolor molecular imaging. In order to demonstrate the performance capabilities of the device, 131I (365 keV), 85SrCl2 (514 keV), and 65ZnCl2 (1116 keV) were injected into a living mouse and the data were taken from 12 angles with a total acquisition time of 2 h. We confirmed that all tracers had accumulated on the target organs of the thyroid, bone, and liver, and that the obtained 3-D image was quantitatively correct with an accuracy of ±20%.

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  • Correction: Shedding new light on the crab with polarized X-rays (Scientific Reports DOI: 10.1038/s41598-017-07390-7)

    M. Chauvin, H. G. Florén, M. Friis, M. Jackson, T. Kamae, J. Kataoka, T. Kawano, M. Kiss, V. Mikhalev, T. Mizuno, N. Ohashi, T. Stana, H. Tajima, H. Takahashi, N. Uchida, M. Pearce

    Scientific Reports   8 ( 1 )  2018.12

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    This Article contains a typographical error in the legend of Figure 2. "Gaussian 1, 2 and 3& #x1D70E;" should read: "Gaussian 1, 2 and 3σ".

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  • Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 6 )  2018.12

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    We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1%±10.6%), and the polarization angle is 110°.7 + 13°.2/-13°.0 in the energy range of 60.160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124°.0 ± 0°.0.1.

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  • Measurement of nuclear reaction cross sections by using Cherenkov radiation toward high-precision proton therapy

    Takamitsu Masuda, Jun Kataoka, Makoto Arimoto, Miho Takabe, Teiji Nishio, Keiichiro Matsushita, Tasuku Miyake, Seiichi Yamamoto, Taku Inaniwa, Toshiyuki Toshito

    Scientific Reports   8 ( 1 ) 2570  2018.12  [Refereed]

     View Summary

    © 2018 The Author(s). Monitoring the in vivo dose distribution in proton therapy is desirable for the accurate irradiation of a tumor. Although positron emission tomography (PET) is widely used for confirmation, the obtained distribution of positron emitters produced by the protons does not trace the dose distribution due to the different physical processes. To estimate the accurate dose from the PET image, the cross sections of nuclear reactions that produce positron emitters are important yet far from being sufficient. In this study, we measured the cross sections of 16O(p,x)15O, 16O(p,x)13N, and 16O(p,x)11C with a wide-energy range (approximately 5-70 MeV) by observing the temporal evolution of the Cherenkov radiation emitted from positrons generated via β + decay along the proton path. Furthermore, we implemented the new cross sectional data into a conventional Monte Carlo (MC) simulation, so that a direct comparison was possible with the PET measurement. We confirmed that our MC results showed good agreement with the experimental data, both in terms of the spatial distributions and temporal evolutions. Although this is the first attempt at using the Cherenkov radiation in the measurements of nuclear cross sections, the obtained results suggest the method is convenient and widely applicable for high precision proton therapy.

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  • Precision imaging of 4.4 MeV gamma rays using a 3-D position sensitive Compton camera

    Ayako Koide, Jun Kataoka, Takamitsu Masuda, Saku Mochizuki, Takanori Taya, Koki Sueoka, Leo Tagawa, Kazuya Fujieda, Takuya Maruhashi, Takuya Kurihara, Taku Inaniwa

    Scientific Reports   8 ( 1 ) 8116  2018.12  [Refereed]

     View Summary

    Imaging of nuclear gamma-ray lines in the 1-10 MeV range is far from being established in both medical and physical applications. In proton therapy, 4.4 MeV gamma rays are emitted from the excited nucleus of either 12C∗or 11B∗and are considered good indicators of dose delivery and/or range verification. Further, in gamma-ray astronomy, 4.4 MeV gamma rays are produced by cosmic ray interactions in the interstellar medium, and can thus be used to probe nucleothynthesis in the universe. In this paper, we present a high-precision image of 4.4 MeV gamma rays taken by newly developed 3-D position sensitive Compton camera (3D-PSCC). To mimic the situation in proton therapy, we first irradiated water, PMMA and Ca(OH)2 with a 70 MeV proton beam, then we identified various nuclear lines with the HPGe detector. The 4.4 MeV gamma rays constitute a broad peak, including single and double escape peaks. Thus, by setting an energy window of 3D-PSCC from 3 to 5 MeV, we show that a gamma ray image sharply concentrates near the Bragg peak, as expected from the minimum energy threshold and sharp peak profile in the cross section of 12C(p,p)12C∗.

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  • Characteristics and Performance of the CALorimetric Electron Telescope (CALET) Calorimeter for Gamma-Ray Observations

    N. Cannady, Y. Asaoka, F. Satoh, M. Tanaka, S. Torii, M. L. Cherry, M. Mori, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, G. Castellini, C. Checchia, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A.De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Astrophysical Journal, Supplement Series   238 ( 1 )  2018.09

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    The CALorimetric Electron Telescope primary detector (CALET-CAL) is a 30 radiation-length-deep hybrid calorimeter designed for the accurate measurement of high-energy cosmic rays. It is capable of triggering on and giving near complete containment of electromagnetic showers from primary electrons and gamma rays from 1 GeV to over 10 TeV. The first 24 months of on-orbit scientific data (2015 November 01-2017 October 31) provide valuable characterization of the performance of the calorimeter based on analyses of the gamma-ray data set in general and bright point sources in particular. We describe the gamma-ray analysis, the expected performance of the calorimeter based on Monte Carlo simulations, the agreement of the flight data with the simulated results, and the outlook for long-term gamma-ray observations with the CAL.

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  • Search for GeV Gamma-Ray Counterparts of Gravitational Wave Events by CALET

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, K. Kohri, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Astrophysical Journal   863 ( 2 )  2018.08  [Refereed]

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    © 2018. The American Astronomical Society. All rights reserved. We present the results of searches for gamma-ray counterparts of the LIGO/Virgo gravitational wave events using CALorimetric Electron Telescope (CALET) observations. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ∼1 GeV up to 10 TeV with a field of view (FOV) of nearly 2 sr. In addition, the CALET gamma-ray burst monitor views ∼3 sr and ∼2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different crystal scintillators. The CALET observations on the International Space Station started in 2015 October, and here we report analyses of events associated with the following gravitational wave events: GW151226, GW170104, GW170608, GW170814, and GW170817. Although only upper limits on gamma-ray emission are obtained, they correspond to a luminosity of 1049 ∼ 1053 erg s-1 in the GeV energy band depending on the distance and the assumed time duration of each event, which is approximately on the order of luminosity of typical short gamma-ray bursts. This implies that there will be a favorable opportunity to detect high-energy gamma-ray emission in further observations if additional gravitational wave events with favorable geometry will occur within our FOV. We also show the sensitivity of CALET for gamma-ray transient events, which is on the order of 10-7 erg cm-2 s-1 for an observation of 100 s in duration.

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  • Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry

    M.Chauvin, G.Floren, M.Jackson

    Nature Astronomy   2 ( 8 ) 652 - 655  2018.08  [Refereed]

     View Summary

    Black hole binary (BHB) systems comprise a stellar-mass black hole and a closely orbiting companion star. Matter is transferred from the companion to the black hole, forming an accretion disk, corona and jet structures. The resulting release of gravitational energy leads to the emission of X-rays1. The radiation is affected by special/general relativistic effects, and can serve as a probe for the properties of the black hole and surrounding environment, if the accretion geometry is properly identified. Two competing models describe the disk–corona geometry for the hard spectral state of BHBs, based on spectral and timing measurements2,3. Measuring the polarization of hard X-rays reflected from the disk allows the geometry to be determined. The extent of the corona differs between the two models, affecting the strength of the relativistic effects (such as enhancement of the polarization fraction and rotation of the polarization angle). Here, we report observational results on the linear polarization of hard X-ray emission (19–181 keV) from a BHB, Cygnus X-14, in the hard state. The low polarization fraction, <8.6% (upper limit at a 90% confidence level), and the alignment of the polarization angle with the jet axis show that the dominant emission is not influenced by strong gravity. When considered together with existing spectral and timing data, our result reveals that the accretion corona is either an extended structure, or is located far from the black hole in the hard state of Cygnus X-1.

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  • Spatial Distribution of the Milky Way Hot Gaseous Halo Constrained by Suzaku X-Ray Observations

    Shinya Nakashima, Yoshiyuki Inoue, Noriko Yamasaki, Yoshiaki Sofue, Jun Kataoka, Kazuhiro Sakai

    Astrophysical Journal   862 ( 1 )  2018.07

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    The formation mechanism of the hot gaseous halo associated with the Milky Way is still under debate. We report new observational constraints on the gaseous halo using 107 lines of sight of the Suzaku X-ray observations at 75°< l < 285° and with a total exposure of 6.4 Ms. The gaseous halo spectra are represented by a singleerature plasma model in collisional ionization equilibrium. The median temperature of the observed fields is 0.26 keV (3.0 × 106 K) with a typical fluctuation of ∼30%. The emission measure varies by an order of magnitude and marginally correlates with the Galactic latitude. Despite the large scatter of the data, the emission measure distribution is roughly reproduced by a disk-like density distribution with a scale length of ∼7 kpc, a scale height of ∼2 kpc, and a total mass of ∼5 × 107 M. In addition, we found that a spherical hot gas with the β-model profile hardly contributes to the observed X-rays but that its total mass might reach 109 M. Combined with indirect evidence of an extended gaseous halo from other observations, the hot gaseous halo likely consists of a dense disk-like component and a rarefied spherical component; the X-ray emissions primarily come from the former, but the mass is dominated by the latter. The disk-like component likely originates from stellar feedback in the Galactic disk due to the low scale height and the large scatter of the emission measures. The median [O/Fe] of ∼0.25 shows the contribution of the core-collapse supernovae and supports the stellar feedback origin.

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  • Diffuse X-Ray Emission from the Northern Arc of Loop i Observed with Suzaku

    Masahiro Akita, Jun Kataoka, Makoto Arimoto, Yoshiaki Sofue, Tomonori Totani, Yoshiyuki Inoue, Shinya Nakashima

    Astrophysical Journal   862 ( 1 ) 88  2018.07  [Refereed]

     View Summary

    © 2018. The American Astronomical Society. All rights reserved. After discovery of the Fermi bubbles, giant structures observed from radio to X-ray monitoring have been widely discussed as possible evidence of past activities in the Galactic center (GC). We report here on the analysis of all the Suzaku archival data pointing around the giant-scale Loop I arc. The diffuse X-ray emission from the northern Loop I arc was well represented by the three-component model: (1) an unabsorbed thermal plasma with kT ≃ 0.1 keV either from the local hot bubble (LHB) and/or solar wind charge exchange (SWCX), (2) an absorbed thermal plasma regarded as a contribution from the Loop I and the Galactic halo (GH), and (3) an absorbed power-law component representing the cosmic X-ray background (CXB). The temperature of the absorbed thermal plasma was narrowly clustered in a range of 0.30 ± 0.02 keV along Loop I ("ON" regions), whereas the temperature was a little lower in the cavity adjacent to the bubbles and Loop I ("OFF" regions) with 0.24 ± 0.03 keV. The emission measure (EM) largely varied along the Galactic latitude b, and was well correlated with the count rate variation as measured with the ROSAT all-sky map in 0.75 keV. Although the amount of neutral gas does not provide any useful constraints on the distance to Loop I, the observed EM values clearly reject a hypothesis that the structure is close to the Sun; we argue that Loop I is a distant, kiloparsec structure in the GH. We discuss the origin of apparent mismatch in the morphologies of the Fermi bubbles and the Loop I arc, suggesting a two-step explosion process in the GC.

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  • On-orbit operations and offline data processing of CALET onboard the ISS

    Y. Asaoka, S. Ozawa, S. Torii, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astroparticle Physics   100   29 - 37  2018.07

     View Summary

    The CALorimetric Electron Telescope (CALET), launched for installation on the International Space Station (ISS) in August, 2015, has been accumulating scientific data since October, 2015. CALET is intended to perform long-duration observations of high-energy cosmic rays onboard the ISS. CALET directly measures the cosmic-ray electron spectrum in the energy range of 1 GeV to 20 TeV with a 2% energy resolution above 30 GeV. In addition, the instrument can measure the spectrum of gamma rays well into the TeV range, and the spectra of protons and nuclei up to a PeV. In order to operate the CALET onboard ISS, JAXA Ground Support Equipment (JAXA-GSE) and the Waseda CALET Operations Center (WCOC) have been established at JAXA and Waseda University, respectively. Scientific operations using CALET are planned at WCOC, taking into account orbital variations of geomagnetic rigidity cutoff. Scheduled command sequences are used to control the CALET observation modes on orbit. Calibration data acquisition by, for example, recording pedestal and penetrating particle events, a low-energy electron trigger mode operating at high geomagnetic latitude, a low-energy gamma-ray trigger mode operating at low geomagnetic latitude, and an ultra heavy trigger mode, are scheduled around the ISS orbit while maintaining maximum exposure to high-energy electrons and other high-energy shower events by always having the high-energy trigger mode active. The WCOC also prepares and distributes CALET flight data to collaborators in Italy and the United States. As of August 31, 2017, the total observation time is 689 days with a live time fraction of the total time of ∼ 84%. Nearly 450 million events are collected with a high-energy (E > 10 GeV) trigger. In addition, calibration data acquisition and low-energy trigger modes, as well as an ultra-heavy trigger mode, are consistently scheduled around the ISS orbit. By combining all operation modes with the excellent-quality on-orbit data collected thus far, it is expected that a five-year observation period will provide a wealth of new and interesting results.

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  • Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   120 ( 26 )  2018.06  [Refereed]

     View Summary

    © 2018 American Physical Society. Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 X0 at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum in the region below 1 TeV shows good agreement with Alpha Magnetic Spectrometer (AMS-02) data. In the energy region below ∼300 GeV, CALET's spectral index is found to be consistent with the AMS-02, Fermi Large Area Telescope (Fermi-LAT), and Dark Matter Particle Explorer (DAMPE), while from 300 to 600 GeV the spectrum is significantly softer than the spectra from the latter two experiments. The absolute flux of CALET is consistent with other experiments at around a few tens of GeV. However, it is lower than those of DAMPE and Fermi-LAT with the difference increasing up to several hundred GeV. The observed energy spectrum above ∼1 TeV suggests a flux suppression consistent within the errors with the results of DAMPE, while CALET does not observe any significant evidence for a narrow spectral feature in the energy region around 1.4 TeV. Our measured all-electron flux, including statistical errors and a detailed breakdown of the systematic errors, is tabulated in the Supplemental Material in order to allow more refined spectral analyses based on our data.

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  • The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations

    K. Tanada, J. Kataoka, M. Arimoto, M. Akita, C. C. Cheung, S. W. Digel, Y. Fukazawa

    Astrophysical Journal   860 ( 1 ) 74  2018.06  [Refereed]

     View Summary

    © 2018. The American Astronomical Society. All rights reserved. We present an analysis of eight years of Fermi-LAT (>0.1 GeV) γ-ray data obtained for the radio galaxy NGC 1275. The γ-ray flux from NGC 1275 is highly variable on short (∼days to weeks) timescales, and has steadily increased over this eight year timespan. By examining the changes in its flux and spectral shape in the LAT energy band over the entire data set, we found that its spectral behavior changed around 2011 February (∼MJD 55600). The γ-ray spectra at early times evolved largely at high energies, while the photon indices were unchanged at later times despite rather large flux variations. To explain these observations, we suggest that the flux changes at the early times were caused by injection of high-energy electrons into the jet while, later, the γ-ray flares were caused by a changing Doppler factor owing to variations in the jet Lorentz factor and/or changes in the angle to our line of sight. To demonstrate the viability of these scenarios, we fit the broad band spectral energy distribution data with a one-zone synchrotron self-Compton (SSC) model for flaring and quiescent intervals before and after 2011 February. To explain the γ-ray spectral behavior in the context of the SSC model, the maximum electron Lorentz factor would have changed at the early times, while a modest change in the Doppler factor adequately fits the quiescent and flaring state γ-ray spectra at the later times.

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  • Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 3 )  2018.06

     View Summary

    We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of 1 = 1.74 ± 0.02 and 2 = 2.14 ± 0.01 below and above the break at 7.1 ± 0.3 keV, which is significantly lower than the NuSTAR result (∼9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833-1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 s. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter.

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  • Development of ultrahigh resolution radiation imaging detector using 1 mm channel size Si-PM array combined with 0.2 mm × 0.2 mm pixelated GAGG plate

    S. Yamamoto, J. Kataoka, T. Fukuchi, K. Kamada, A. Yoshikawa

    Journal of Instrumentation   13 ( 5 ) P05028  2018.05

     View Summary

    For precise distribution measurements of gamma photons or beta particles, high resolution radiation imaging detectors are required. Reducing the size of the photodetectors combined with small pixel scintillators is a possible method to improve the spatial resolution of the scintillator based radiation imaging detectors. In this paper, we used a 1mm channel size silicon photomultiplier (Si-PM) array combined with a small pixel scintillator array and evaluated the performance for gamma photons and beta particles. For the radiation imaging detector, a Si-PM array with 1mm × 1mm channel size arranged in 8 × 8 (Hamamatsu, S13615-1025N-08) was optically coupled to a 0.2 mm × 0.2 mm pixelated GAGG plate. For 662 keV high energy gamma photons, 0.2mm GAGG pixels were clearly resolved in the position histogram. The peak to valley ratio (P/V) of the position histogram was not improved when only photo-peak events were used while it was improved when the events lower energy than the Compton edge was used. We could also resolve the position histograms for both 122 keV and 60 keV gamma photons. For beta particles, although the position histogram showed good separation for relatively low energy beta particles of Ca-45 (245 keV max), separation became worse for higher energy beta particles from Sr-Y-90 (545keV and 2280keV max). The separation of the position histogram for Sr-Y-90 improved when only lower energy events were used. Using 1mm size Si-PM array, high resolution detectors was realized for low energy gamma photons and beta particle but the spatial resolution was decreased for high energy beta particles from Sr-Y-90.

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  • Modeling of proton-induced radioactivation background in hard X-ray telescopes: Geant4-based simulation and its demonstration by Hitomi's measurement in a low Earth orbit

    Odaka Hirokazu, Asai Makoto, Hagino Kouichi, Koi Tatsumi, Madejski Greg, Mizuno Tsunefumi, Ohno Masanori, Saito Shinya, Sato Tamotsu, Wright Dennis H, Enoto Teruaki, Fukazawa Yasushi, Hayashi Katsuhiro, Kataoka Jun, Katsuta Junichiro, Kawaharada Madoka, Kobayashi Shogo B, Kokubun Motohide, Laurent Philippe, Lebrun Francois, Limousin Olivier, Maier Daniel, Makishima Kazuo, Mimura Taketo, Miyake Katsuma, Mori Kunishiro, Murakami Hiroaki, Nakamori Takeshi, Nakano Toshio, Nakazawa Kazuhiro, Noda Hirofumi, Ohta Masayuki, Ozaki Masanobu, Sato Goro, Sato Rie, Tajima Hiroyasu, Takahashi Hiromitsu, Takahashi Tadayuki, Takeda Shin'ichiro, Tanaka Takaaki, Tanaka Yasuyuki, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Watanabe Shin, Yamaoka Kazutaka, Yasuda Tetsuya, Yatsu Yoichi, Yuasa Takayuki, Zoglauer Andreas

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   891   92 - 105  2018.05  [Refereed]

     View Summary

    Hard X-ray astronomical observatories in orbit suffer from a significant amount of background due to radioactivation induced by cosmic-ray protons and/or geomagnetically trapped protons. Within the framework of a full Monte Carlo simulation, we present modeling of in-orbit instrumental background which is dominated by radioactivation. To reduce the computation time required by straightforward simulations of delayed emissions from activated isotopes, we insert a semi-analytical calculation that converts production probabilities of radioactive isotopes by interaction of the primary protons into decay rates at measurement time of all secondary isotopes. Therefore, our simulation method is separated into three steps: (1) simulation of isotope production, (2) semi-analytical conversion to decay rates, and (3) simulation of decays of the isotopes at measurement time. This method is verified by a simple setup that has a CdTe semiconductor detector, and shows a 100-fold improvement in efficiency over the straightforward simulation. To demonstrate its experimental performance, the simulation framework was tested against data measured with a CdTe sensor in the Hard X-ray Imager onboard the Hitomi X-ray Astronomy Satellite, which was put into a low Earth orbit with an altitude of 570 km and an inclination of 31°, and thus experienced a large amount of irradiation from geomagnetically trapped protons during its passages through the South Atlantic Anomaly. The simulation is able to treat full histories of the proton irradiation and multiple measurement windows. The simulation results agree very well with the measured data, showing that the measured background is well described by the combination of proton-induced radioactivation of the CdTe detector itself and thick Bi4Ge3O12 scintillator shields, leakage of cosmic X-ray background and albedo gamma-ray radiation, and emissions from naturally contaminated isotopes in the detector system.

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  • In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)

    Kouichi Hagino, Kazuhiro Nakazawa, Goro Sato, Motohide Kokubun, Teruaki Enoto, Yasushi Fukazawa, Katsuhiro Hayashi, Jun Kataoka, Junichiro Katsuta, Shogo B. Kobayashi, Philippe Laurent, Francois Lebrun, Olivier Limousin, Daniel Maier, Kazuo Makishima, Taketo Mimura, Katsuma Miyake, Tsunefumi Mizuno, Kunishiro Mori, Hiroaki Murakami, Takeshi Nakamori, Toshio Nakano, Hirofumi Noda, Hirokazu Odaka, Masanori Ohno, Masayuki Ohta, Shinya Saito, Rie Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin'ichiro Takeda, Takaaki Tanaka, Yukikatsu Terada, Hideki Uchiyama, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Yoichi Yatsu, Takayuki Yuasa

    Journal of Astronomical Telescopes, Instruments, and Systems   4 ( 2 )  2018.04

     View Summary

    The Hard X-ray Imager (HXI) onboard Hitomi (ASTRO-H) is an imaging spectrometer covering hard x-ray energies of 5 to 80 keV. Combined with the Hard X-ray Telescope, it enables imaging spectroscopy with an angular resolution of 10.7 half-power diameter, in a field of view of 9' × 9'. The main imager is composed of four layers of Si detectors and one layer of CdTe detector, stacked to cover a wide energy band up to 80 keV, surrounded by an active shield made of Bi4Ge3O12 scintillator to reduce the background. The HXI started observations 12 days before the Hitomi loss and successfully obtained data from G21.5-0.9, Crab, and blank sky. Utilizing these data, we calibrate the detector response and study properties of in-orbit background. The observed Crab spectra agree well with a powerlaw model convolved with the detector response, within 5% accuracy. We find that albedo electrons in specified orbit strongly affect the background of the Si top layer and establish a screening method to reduce it. The background level over the full field of view after all the processing and screening is as low as the preflight requirement of 1 - 3 × 10-4 counts s-1 cm-2 keV-1.

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  • Design and performance of Soft Gamma-ray Detector onboard the Hitomi (ASTRO-H) satellite

    Tajima Hiroyasu, Watanabe Shin, Fukazawa Yasushi, Blandford Roger, Enoto Teruaki, Goldwurm Andrea, Hagino Kouichi, Hayashi Katsuhiro, Ichinohe Yuto, Kataoka Jun, Katsuta Jun'ichiro, Kitaguchi Takao, Kokubun Motohide, Laurent Philippe, Lebrun Francois, Limousin Olivier, Madejski Grzegorz M, Makishima Kazuo, Mizuno Tsunefumi, Mori Kunishiro, Nakamori Takeshi, Nakano Toshio, Nakazawa Kazuhiro, Noda Hirofumi, Odaka Hirokazu, Ohno Masanori, Ohta Masayuki, Saito Shinya, Sato Goro, Sato Rie, Takeda Shin'ichiro, Takahashi Hiromitsu, Takahashi Tadayuki, Tanaka Takaaki, Tanaka Yasuyuki, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Yamaoka Kazutaka, Yatsu Yoichi, Yonetoku Daisuke, Yuasao Takayuki

    JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS   4 ( 2 )  2018.04  [Refereed]

     View Summary

    Hitomi (ASTRO-H) was the sixth Japanese X-ray satellite that carried instruments with exquisite energy resolution of <7 eV and broad energy coverage of 0.3 to 600 keV. The Soft Gamma-ray Detector (SGD) was the Hitomi instrument that observed the highest energy band (60 to 600 keV). The SGD design achieves a low background level by combining active shields and Compton cameras where Compton kinematics is utilized to reject backgrounds coming from outside of the field of view. A compact and highly efficient Compton camera is realized using a combination of silicon and cadmium telluride semiconductor sensors with a good energy resolution. Compton kinematics also carries information for gamma-ray polarization, making the SGD an excellent polarimeter. Following several years of development, the satellite was successfully launched on February 17, 2016. After proper functionality of the SGD components were verified, the nominal observation mode was initiated on March 24, 2016. The SGD observed the Crab Nebula for approximately two hours before the spacecraft ceased to function on March 26, 2016. We present concepts of the SGD design followed by detailed description of the instrument and its performance measured on ground and in orbit.

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  • Hard x-ray imager onboard Hitomi (ASTRO-H)

    Nakazawa Kazuhiro, Sato Goro, Kokubun Motohide, Enoto Teruaki, Fukazawa Yasushi, Hagino Kouichi, Hayashi Katsuhiro, Kataoka Jun, Katsuta Junichiro, Kobayashi Shogo B, Laurent Philippe, Lebrun Francois, Limousin Olivier, Maier Daniel, Makishima Kazuo, Mizuno Tsunefumi, Mori Kunishiro, Nakamori Takeshi, Nakano Toshio, Noda Hirofumi, Odaka Hirokazu, Ohno Masanori, Ohta Masayuki, Saito Shinya, Sato Rie, Tajima Hiroyasu, Takahashi Hiromitsu, Takahashi Tadayuki, Takeda Shin'ichiro, Tanaka Takaaki, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Watanabe Shin, Yamaoka Kazutaka, Yatsu Yoichi, Yuasa Takayuki

    JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS   4 ( 2 )  2018.04  [Refereed]

     View Summary

    The hard x-ray imaging spectroscopy system of "Hitomi" x-ray observatory is composed of two sets of hard x-ray imagers (HXI) coupled with hard x-ray telescopes (HXT). With a 12-m focal length, the system provides fine (10:7 half-power diameter) imaging spectroscopy covering about 5 to 80 keV. The HXI sensor consists of a camera, which is composed of four layers of Si and one layer of CdTe semiconductor imagers, and an active shield composed of nine Bi4Ge3O12 scintillators to provide low background. The two HXIs started observation on March 8 and 14, 2016 and were operational until 26 March. Using a Crab observation, 5 to 80 keV energy coverage and good detection efficiency were confirmed. The detector background level of 1 to 3 × 10-4 counts s?1 keV?1 cm?2 (in detector geometrical area) at 5 to 80 keV was achieved, by cutting the high-background time-intervals, adopting sophisticated energy-dependent imager layer selection, and baffling of the cosmic x-ray background and active-shielding. This level is among the lowest of detectors working in this energy band. By comparing the effective area and the background, it was shown that the HXI had a sensitivity that is same to that of NuSTAR for point sources and 3 to 4 times better for largely extended diffuse sources.

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  • Hitomi observation of radio galaxy NGC 1275: The first X-ray microcalorimeter spectroscopy of Fe-Kα line emission from an active galactic nucleus

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier O. Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    The origin of the narrow Fe-Kα fluorescence line at 6.4 keV from active galactic nuclei has long been under debate; some of the possible sites are the outer accretion disk, the broad line region, a molecular torus, or interstellar/intracluster media. In 2016 February-March, we performed the first X-ray microcalorimeter spectroscopy with the Soft X-ray Spectrometer (SXS) on board the Hitomi satellite of the Fanaroff-Riley type I radio galaxy NGC 1275 at the center of the Perseus cluster of galaxies. With the high-energy resolution of ∼5 eV at 6 keV achieved by Hitomi/SXS, we detected the Fe-Kα line with ∼5.4 σ significance. The velocity width is constrained to be 500-1600 km s−1 (FWHM for Gaussian models) at 90% confidence. The SXS also constrains the continuum level from the NGC 1275 nucleus up to ∼20 keV, giving an equivalent width of ∼20 eV for the 6.4 keV line. Because the velocity width is narrower than that of the broad Hα line of ∼2750 km s−1, we can exclude a large contribution to the line flux from the accretion disk and the broad line region. Furthermore, we performed pixel map analyses on the Hitomi/SXS data and image analyses on the Chandra archival data, and revealed that the Fe-Kα line comes from a region within ∼1.6 kpc of the NGC 1275 core, where an active galactic nucleus emission dominates, rather than that from intracluster media. Therefore, we suggest that the source of the Fe-Kα line from NGC 1275 is likely a low-covering-fraction molecular torus or a rotating molecular disk which probably extends from a parsec to hundreds of parsecs scale in the active galactic nucleus system.

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  • Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer

    Takashi J. Moriya, Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan Mccammon, Brian R. Mcnamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    The Crab nebula originated from a core-collapse supernova (SN) explosion observed in 1054AD. When viewed as a supernova remnant (SNR), it has an anomalously low observed ejecta mass and kinetic energy for an Fe-core-collapse SN. Intensive searches have been made for a massive shell that solves this discrepancy, but none has been detected. An alternative idea is that SN 1054 is an electron-capture (EC) explosion with a lower explosion energy by an order of magnitude than Fe-core-collapse SNe. X-ray imaging searches were performed for the plasma emission from the shell in the Crab outskirts to set a stringent upper limit on the X-ray emitting mass. However, the extreme brightness of the source hampers access to its vicinity. We thus employed spectroscopic technique using the X-ray micro-calorimeter on board the Hitomi satellite. By exploiting its superb energy resolution, we set an upper limit for emission or absorption features from as yet undetected thermal plasma in the 2-12keV range. We also re-evaluated the existing Chandra and XMM-Newton data. By assembling these results, a new upper limit was obtained for the X-ray plasma mass of < 1 M⊙ for a wide range of assumed shell radius, size, and plasma temperature values both in and out of collisional equilibrium. To compare with the observation, we further performed hydrodynamic simulations of the Crab SNR for two SN models (Fe-core versus EC) under two SN environments (uniform interstellar medium versus progenitor wind). We found that the observed mass limit can be compatible with both SN models if the SN environment has a low density of < 0.03 cm-3 (Fe core) or < 0.1 cm-3 (EC) for the uniform density, or a progenitor wind density somewhat less than that provided by a mass loss rate of 10-5M⊙ yr-1 at 20 km s-1for the wind environment.

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  • Glimpse of the highly obscured HMXB IGR J16318-4848 with Hitomi

    Steven W. Alle, Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier O. Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan Mccammon, Brian R. Mcnamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    We report on a Hitomi observation of IGRJ16318-4848, a high-mass X-ray binary system with an extremely strong absorption of NH ∼ 1024cm 2. Previous X-ray studies revealed that its spectrum is dominated by strong fluorescence lines of Fe as well as continuum emission lines. For physical and geometrical insight into the nature of the reprocessing material, we utilized the high spectroscopic resolving power of the X-ray microcalorimeter (the soft X-ray spectrometer: SXS) and the wide-band sensitivity by the soft and hard X-ray imagers (SXI and HXI) aboard Hitomi. Even though the photon counts are limited due to unintended off-axis pointing, the SXS spectrum resolves Fe Kα1 and Kα2 lines and puts strong constraints on the line centroid and line width. The line width corresponds to a velocity of 160+-37000 km s-1. This represents the most accurate, and smallest, width measurement of this line made so far from the any X-ray binary, much less than the Doppler broadening and Doppler shift expected from speeds that are characteristic of similar systems. Combined with the K-shell edge energy measured by the SXI and HXI spectra, the ionization state of Fe is estimated to be in the range of Fe I-IV. Considering the estimated ionization parameter and the distance between the X-ray source and the absorber, the density and thickness of the materials are estimated. The extraordinarily strong absorption and the absence of a Compton shoulder component have been confirmed. These characteristics suggest reprocessing materials that are distributed in a narrow solid angle or scattering, primarily by warm free electrons or neutral hydrogen. This measurement was achieved using the SXS detection of 19 photons. It provides strong motivation for follow-up observations of this and other X-ray binaries using the X-ray Astrophysics Recovery Mission and other comparable future instruments.

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  • Hitomi X-ray studies of giant radio pulses from the Crab pulsar

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, L. E.E. Shiu-Hang, Maurice A. Leutenegger, Olivier O. Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2-300 keV band and the Kashima NICT radio telescope in the 1.4-1.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 σ fluctuations of the X-ray fluxes at the pulse peaks, and the 3 σ upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2-300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and 70-300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) × 10−11 erg cm−2, respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a >0.02% brightening of the pulse-peak flux under such conditions.

  • Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Maki Furukawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier O. Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    Thanks to its high spectral resolution (∼5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus Cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering effect should be taken into account. In the Hitomi waveband, resonant scattering mostly affects the Fe XXV Heα line (w)-the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor of ∼1.3 in the inner ∼30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The w line also appears slightly broader than other lines from the same ion. The observed distortions of the w line flux, shape, and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick (w) and thin (Fe XXV forbidden, Heβ, Lyα) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions offering similar or better capabilities to the Hitomi SXS, will enable resonant scattering measurements to provide powerful constraints on the amplitude and anisotropy of cluster gas motions.

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  • Hitomi observations of the LMC SNR N 132 D: Highly redshifted X-ray emission from iron ejecta

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    We present Hitomi observations of N 132 D, a young, X-ray bright, O-rich core-collapse supernova remnant in the Large Magellanic Cloud (LMC). Despite a very short observation of only 3.7 ks, the Soft X-ray Spectrometer (SXS) easily detects the line complexes of highly ionized S K and Fe K with 16-17 counts in each. The Fe feature is measured for the first time at high spectral resolution. Based on the plausible assumption that the Fe K emission is dominated by He-like ions, we find that the material responsible for this Fe emission is highly redshifted at ∼ 800 km s−1 compared to the local LMC interstellar medium (ISM), with a 90% credible interval of 50-1500 km s−1 if a weakly informative prior is placed on possible line broadening. This indicates (1) that the Fe emission arises from the supernova ejecta, and (2) that these ejecta are highly asymmetric, since no blueshifted component is found. The S K velocity is consistent with the local LMC ISM, and is likely from swept-up ISM material. These results are consistent with spatial mapping that shows the He-like Fe concentrated in the interior of the remnant and the S tracing the outer shell. The results also show that even with a very small number of counts, direct velocity measurements from Doppler-shifted lines detected in extended objects like supernova remnants are now possible. Thanks to the very low SXS background of ∼ 1 event per spectral resolution element per 100 ks, such results are obtainable during short pointed or slew observations with similar instruments. This highlights the power of high-spectral-resolution imaging observations, and demonstrates the new window that has been opened with Hitomi and will be greatly widened with future missions such as the X-ray Astronomy Recovery Mission (XARM) and Athena.

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  • Temperature structure in the Perseus cluster core observed with Hitomi

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Maki Furukawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Yuichi Kato, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of ∼7 in diameter. SXS was operated with an energy resolution of ∼5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions, but also transitions from higher principal quantum numbers were clearly resolved from Si through Fe. That enabled us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single-temperature thermal plasma model in collisional ionization equilibrium, but detailed line-ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with the atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures could be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single-temperature approximation are due to the effects of projecting the known radial temperature gradient in the cluster core along the line of sight. A comparison with the Chandra/ACIS and the XMM-Newton/RGS results, on the other hand, suggests that additional lower-temperature components are present in the intracluster medium (ICM), but not detectable with Hitomi/SXS giving its 1.8-20 keV energy band.

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  • Atmospheric gas dynamics in the Perseus cluster observed with Hitomi

    Felix Aharonia, Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Rebecca E.A. Canning, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Tasuku Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Shota Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan Mccammon, Brian R. Mcnamara

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100kpc of the Perseus cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches a maxima of approximately 200 km s-1 toward the central active galactic nucleus (AGN) and toward the AGN inflated northwestern "ghost" bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100 km s-1. We also detect a velocity gradient with a 100 km s-1 amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10% of the thermal pressure support in the cluster core. The well-resolved, optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100 kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift of the brightest cluster galaxy NGC 1275.

  • Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Cor P. De Vries, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Natalie Hell, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu Hang Lee, Maurice A. Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller

    Publications of the Astronomical Society of Japan   70 ( 2 )  2018.03

     View Summary

    The Hitomi Soft X-ray Spectrometer spectrum of the Perseus cluster, with ∼5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic data and models. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that accurate atomic data and models are as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current data and models ready for the data from the next Hitomi-level mission.

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  • X-ray and gamma-ray observations of the fermi bubbles and NPS/Loop I structures

    Jun Kataoka, Yoshiaki Sofue, Yoshiyuki Inoue, Masahiro Akita, Shinya Nakashima, Tomonori Totani

    Galaxies   6 ( 1 ) 27 - 46  2018.02  [Refereed]  [Invited]

     View Summary

    The Fermi bubbles were possibly created by large injections of energy into the Galactic Center (GC), either by an active galactic nucleus (AGN) or by nuclear starburst more than ~10 Myr ago. However, the origin of the diffuse gamma-ray emission associated with Loop I, a radio continuum loop spanning across 100° on the sky, is still being debated. The northern-most part of Loop I, known as the North Polar Spur (NPS), is the brightest arm and is even clearly visible in the ROSAT X-ray sky map. In this paper, we present a comprehensive review on the X-ray observations of the Fermi bubbles and their possible associationwith theNPS and Loop I structures. Using uniform analysis of archival Suzaku and Swift data, we show that X-ray plasma with kT~0.3 keV and low metal abundance (Z~0.2 Z⊙) is ubiquitous in both the bubbles and Loop I and is naturally interpreted as weakly shock-heated Galactic halo gas. However, the observed asymmetry of the X-ray-emitting gas above and below the GC has still not been resolved
    it cannot be fully explained by the inclination of the axis of the Fermi bubbles to the Galactic disk normal. We argue that the NPS and Loop I may be asymmetric remnants of a large explosion that occurred before the event that created the Fermi bubbles, and that the soft gamma-ray emission from Loop I may be due to either π0 decay of accelerated protons or electron bremsstrahlung.

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  • Evaluation of GAGG:Ce scintillators for future space applications

    M. Yoneyama, J. Kataoka, M. Arimoto, T. Masuda, M. Yoshino, K. Kamada, A. Yoshikawa, H. Sato, Y. Usuki

    Journal of Instrumentation   13 ( 2 ) P020203  2018.02  [Refereed]

     View Summary

    © 2018 IOP Publishing Ltd and Sissa Medialab. Cerium-doped Gd3(Ga, Al)5O12 (GAGG:Ce) is a promising novel scintillator for gamma-ray detectors. While GAGG:Ce has already been implemented in various commercial products, its detailed characteristics and response to high-energy particles and gamma rays remain unknown. In particular, knowledge is lacking on the radiation tolerance of this scintillator against the gamma-ray and proton irradiation expected in future space satellite mission applications. In this study, we first investigate the light-yield energy dependence, energy resolution, decay time, radiation tolerance, and afterglow of GAGG:Ce scintillators under various temperature conditions. We find excellent linearity of ±3% between light yields and deposited energy over a wide range of 30-1836 keV; however, a light-yield deficit of more than 10% is observed below 30 keV of deposited gamma ray energy. We confirm that the temperature dependence of the light yield, energy resolution, and scintillation decay time is within 5-20% between -20 and 20C. We also evaluate the GAGG:Ce activation characteristics under proton irradiation and the light-yield degradation by accumulated dose using a 60Co source. Moreover, we successfully identify various gamma-ray lines due to activation. Finally, we find a substantial afterglow for GAGG:Ce scintillators over a few hours; such an afterglow is only minimally observed in other scintillators such as CsI:Tl and Bi4Ge3O12 (BGO). However, the afterglow can be substantially reduced through additional co-doping with divalent metal ions, such as Mg ions. These results suggest that GAGG:Ce is a promising scintillator with potential application in space satellite missions in the near future.

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  • The PoGO+ view on Crab off-pulse hard X-ray polarisation

    M.Chauvin, G.Floren, M.Jackson

    Monthly Notices of the Royal Astronomical Society: Letters,   477 ( 1 ) 45 - 49  2018.02  [Refereed]

     View Summary

    The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.

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  • Detecting polarization of gamma rays from Crab Nebula with Hitomi Soft Gamma-ray Detector(SGD)

    Watanabe Shin, Ohno Masanori, Odaka Hirokazu, Kataoka Jun, Katsuta Junichiro, Kitaguchi Takao, Kokubun Motohide, Goldwurm Andrea, Saito Shinya, Sato Goro, Sato Rie, Uchida Yusuke, Takahashi Tadayuki, Takahashi Hiromitsu, Takeda Shin'ichiro, Tanaka Takaaki, Tanaka Yasuyuki, Terada Yukikatsu, Nakazawa Kazuhiro, Nakano Toshio, Nakamori Takashi, Noda Hirofumi, Tajima Hiroyasu, Hagino Kouichi, Hayashi Katsuhiro, Blandford Roger, Makishima Kazuo, Madejski Grzegorz, Mizuno Tsunefumi, Mori Kunishiro, Yatsu Yoichi, Yamaoka Kazutaka, Yuasa Takayuki, Fukazawa Yasushi, Yonetoku Daisuke, Laurent Philippe, Limousin Olivier, Lebrun François, the SGD team, Ichinohe Yuto, Uchiyama Hideki, Uchiyama Yasunobu, Enoto Teruaki, Ohta Masayuki

    Meeting Abstracts of the Physical Society of Japan   73   492 - 492  2018

    DOI CiNii

  • CTA Report 134:Study of the aging effect of the photomultiplier tube for the CTA Large Size Telescope

    Sakurai S., Kataoka J., Katagiri H., Kimura S., Kushida J., Kubo H., Gunji S., Koyama S., Konno Y., Saito T., Sawada M., Nagayoshi T., Sunada Y., Takahashi M., Tsujimoto S., Teshima M., Terada Y., Tokanai F., Nakajima D., Nakamori T., Nishijima K., Nishiyama G., Inada T., Nozaki S., Hayashida M., Bamba A., Hirako J., Fukami S., Masuda S., Yamamoto T., Yoshida T., Hadasch D., Mazin D., Inome Y., the CTA-Japan consortium, Iwamura Y., Ohoka H., Okumura A., Okazaki N., Orito R.

    Meeting Abstracts of the Physical Society of Japan   73 ( 0 ) 417 - 417  2018

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  • CTA Report 133: Integration test of the focal plane camera for the first CTA Large Sized Telescope

    Nozaki S., Katagiri H., Kato S., Kimura S., Kushida J., Kubo H., Gunji S., Koyama S., Konno Y., Saito T., Sakurai S., Inada T., Sawada M., Sunada Y., Takahashi M., Takahara H., Tanaka M., Tsujimoto S., Teshima M., Terada Y., Okanai F., NakajimaT D., Inome Y., Nakamori T., Nagayoshi T., Nishijima K., Nishiyama G., Hayashida M., Bamba A., Hirako J., Fukami S., Masuda S., Yamamoto T., Iwamura Y., Yoshida T., Hadasch D., Mazin D., the CTA-Japan consortium, Ikeno M., Uchida T., Ohoka H., Okumura A., Okazaki N., Orito R., Kataoka J.

    Meeting Abstracts of the Physical Society of Japan   73 ( 0 ) 416 - 416  2018

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  • CTA Report 142: Integration test of the focal plane camera for the first CTA Large Sized Telescope(II)

    Sunada Y., Katagiri H., Kushida J., Kimura S., Kubo H., Gunji S., Koyama S., Saito T., Sakurai S., Sawada M., Suzuki M., Inada T., Takahashi M., Takahara H., Tanaka M., Tujimoto S., Teshima M., Terada Y., Tokanai F., Nakajima D., Nakamori K., Nagayoshi T., Inome Y., Nishijima K., Nishiyama G., Nozaki S., Hayashida M., Bamba A., Hirako J., Fukami S., Masuda S., Yamamoto T., Yoshida T., Iwamura Y., Hadasch Daniela, Mazin Daniel, the CTA-Japan consortium, Ohoka H., Okazaki N., Okumura A., Orito R., Kataoka J.

    Meeting Abstracts of the Physical Society of Japan   73 ( 0 ) 191 - 191  2018

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  • Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Physical Review Letters   119 ( 18 )  2017.11

     View Summary

    First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X0 and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152±0.016 (stat+syst). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.

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  • Solar abundance ratios of the iron-peak elements in the Perseus cluster

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Jelle De Plaa, Jan-Willem den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko S. Hiraga, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masachika Iwai, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Nobuyuki Kawai, Richard L. Kelley, Caroline A. Kilbourne, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Katsuji Koyama, Shu Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Shiu-Hang Lee, Maurice A. Leutenegger, Olivier Limousine, Michael Loewenstein, Knox S. Long, David Lumb, Greg Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian R. McNamara, Missagh Mehdipour, Eric D. Miller, Jon M. Miller, Shin Mineshige, Kazuhisa Mitsuda, Ikuyuki Mitsuishi, Takuya Miyazawa, Tsunefumi Mizuno, Hideyuki Mori, Koji Mori, Koji Mukai, Hiroshi Murakami, Richard F. Mushotzky, Takao Nakagawa, Hiroshi Nakajima, Takeshi Nakamori, Shinya Nakashima, Kazuhiro Nakazawa, Kumiko K. Nobukawa, Masayoshi Nobukawa, Hirofumi Noda, Hirokazu Odaka, Takaya Ohashi, Masanori Ohno, Takashi Okajima, Naomi Ota, Masanobu Ozaki, Frits Paerels, StPhane Paltani, Robert Petre, Ciro Pinto, Frederick S. Porter, Katja Pottschmidt, Christopher S. Reynolds, Samar Safi-Harb, Shinya Saito, Kazuhiro Sakai, Toru Sasaki, Goro Sato, Kosuke Sato, Rie Sato, Makoto Sawada, Norbert Schartel, Peter J. Serlemitsos, Hiromi Seta, Megumi Shidatsu, Aurora Simionescu, Randall K. Smith, Yang Soong, Lukasz Stawarz, Yasuharu Sugawara, Satoshi Sugita, Andrew Szymkowiak, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin'ichiro Takeda, Yoh Takei, Toru Tamagawa, Takayuki Tamura, Takaaki Tanaka, Yasuo Tanaka, Yasuyuki T. Tanaka, Makoto S. Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Francesco Tombesi, Hiroshi Tomida, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi Go Tsuru, Hiroyuki Uchida, Hideki Uchiyama, Yasunobu Uchiyama, Shutaro Ueda, Yoshihiro Ueda, Shin'ichiro Uno, C. Megan Urry, Eugenio Ursino, Cor P. de Vries, Shin Watanabe, Norbert Werner, Daniel R. Wik, Dan R. Wilkins, Brian J. Williams, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Y. Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Yoichi Yatsu, Daisuke Yonetoku, Irina Zhuravleva, Abderahmen Zoghbi

    NATURE   551 ( 7681 ) 478 - +  2017.11  [Refereed]

     View Summary

    The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae(1). Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode(2-6). Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun(7-11), suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, highresolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations(12-14) disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near-and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment(5,15,16).

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  • Development of a new pinhole camera for imaging in high dose-rate environments

    K.Sueoka

    Nuclear Instruments and Methods in Physics Research Section A   912   115 - 118  2017.11  [Refereed]

     View Summary

    After Fukushima's nuclear disaster in Japan, the decontamination operation is successfully ongoing, and restrictions from some areas were lifted in April 2017. However, the radiation dose rate in the Fukushima Daiichi Plant is still so high (e.g., from a few mSv/h up to 530 Sv/h) that the decommissioning operation of the reactor remains a serious problem. Visualization of radioactive materials would help address this, but no gamma camera is available at this moment that can take images in such a high dose-rate environment. In this study, we developed a new gamma camera featuring a wide dynamic range from sub-mSv/h to more than 680 Sv/h, for a quick and accurate visualization of radioactive materials. The camera consists of a pinhole collimator, a Gd2O2S:Tb (GOS) scintillator sheet, and an electron multiplying charge-coupled device (EM-CCD). Gamma rays passing through the pinhole collimator hit the GOS scintillator sheet, which emits scintillation light. The luminescence of the GOS scintillator sheet is monitored in real-time with an EM-CCD with an internal multiplication gain of up to 20. By changing the exposure time, electron multiplication gain, and aperture of the EM-CCD, a wider dynamic range covering five orders of magnitude in the radiation dose can be monitored for the first time. We show that the positions of a 137Cs source (662 keV) and 60Co source (1173, 1333 keV) are identified correctly with a typical angular resolution of 10° full width at half maximum (FWHM). We also confirmed a linear relation between the absorbed dose and the luminescence of the GOS scintillator sheet. Finally, we propose a new concept of ”color imaging”, by using multi-layered scintillators consisting of a Ga3Al2Gd3O12 (GAGG) scintillator, fluorescent glass, and a plastic scintillator.

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  • Spatially resolved measurement of wideband prompt gamma-ray emission toward on-line monitor for the future proton therapy

    A.Koide

    Nuclear Instruments and Methods in Physics Research Section A   912   24 - 28  2017.11  [Refereed]

     View Summary

    In proton therapy, the delivered dose should be monitored to a high degree of accuracy to avoid unnecessary exposure to healthy tissues and critical organs. Although positron emission tomography (PET) is most frequently used to verify the proton range, the nuclear reactions between protons and nuclei that generate positrons do not necessarily correspond to the actual proton range. Moreover, such imaging must be conducted after the treatment irradiation, because a PET gantry cannot be used in conjunction with a proton therapy beam. In this paper, we studied one-dimensional (1D) and two-dimensional (2D) distributions of prompt gamma rays of various energies, to determine the most suitable energy window for online monitoring in proton therapy. After an initial simulation study using the particle and heavy ion transport code system (PHITS), we irradiated a poly(methyl methacrylate) (PMMA) phantom with a 70-MeV proton beam to mimic proton range verification in a clinical situation. Using a newly developed Compton camera, we have experimentally confirmed for the first time that 4.4-MeV gamma rays emitted from 12C and 16O match the exact position of the Bragg peak in proton range verification.

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    3
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  • Development of LSI for a new kind of photon-counting computed tomography using multipixel photon counters

    M.Arimoto

    Nuclear instruments & methods in physics research. Section A   912   186 - 190  2017.11  [Refereed]

     View Summary

    X-ray imaging with computed tomography (CT) is widely used for nondestructive imaging of the interior of the human body. In the next decade, photon-counting X-ray CT is expected to reduce the dose needed and enable multicolor imaging. Recently, we proposed a novel photon-counting method that uses a multipixel photon counter (MPPC), with a significantly high signal gain (∼106) and fast temporal response (a few nanoseconds), combined with a high-speed scintillator. To realize photon-counting CT imaging in a wide area irradiated by an extremely high X-ray flux (106-107 Hz/mm2), a multichannel MPPC system is required. Thus, we developed a large-scale integrated circuit (LSI) with ultrafast signal-processing capability for use with a 16-channel MPPC. The developed LSI can extract a pulse current from an MPPC array with a large detector capacitance (∼200 pF) by utilizing an electrical circuit with low input impedance. The LSI offers a high photon count rate above 25 MHz/pixel with noise equal to 1.7 μA for a dynamic range of ∼ 1.3 mA and an energy resolution of 32 % (FWHM) at 60 keV, thereby enabling ultrafast multicolor CT imaging.

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    10
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  • Performance comparison of finely pixelated LYSO- and GAGG- based Si-PM gamma cameras for high resolution SPECT

    Kouhei Nakanishi, Seiichi Yamamoto, Jun Kataoka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   872 ( 11 ) 107 - 111  2017.11  [Refereed]

     View Summary

    Although Lu-based scintillators, including Ce-doped Lu1.8Y0.2SiO5 (LYSO) scintillators, are often used for positron emission tomography (PET) detectors, they are not commonly used in gamma cameras for single-photon emission computed tomography (SPECT) because background counts due to contamination of the natural radioisotope in Lu are detected. However, several studies report that deterioration in image contrast due to background counts of the natural radioisotope is not critical and thus LYSO is promising for use in SPECT detectors. Meanwhile, a new scintillator, the Ce-doped Gd3Al2Ga3O12 (GAGG) with a high light yield and no natural radioisotope, has been developed and is also thought to be a promising scintillator. Thus, we compared the performance of LYSO with that of GAGG to determine which is more appropriate for a silicon photomultiplier (Si-PM)-based high-resolution small field-of-view (FOV) gamma camera for SPECT. We used finely pixelated LYSO and GAGG plates that were optically coupled to Si-PM arrays to form gamma cameras and measured the basic performance for 122-keV gamma photons. The energy resolutions of the LYSO-and GAGG-based Si-PM gamma cameras were 30% and 23% full width at half maximum (FWHM), respectively. The intrinsic spatial resolution of the GAGG (similar to 0.5 mm FWHM) based gamma camera was better than that of the LYSO (similar to 0.6 mm FWHM). The background counts of the LYSO-based gamma camera were 28 times larger than that of the GAGG. Based on these results, we conclude that GAGG is more appropriate than LYSO for the development of a Si-PM based gamma camera for high resolution SPECT. (C) 2017 Elsevier B. V. All rights reserved.

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  • First demonstration of aerial gamma-ray imaging using drone for prompt radiation survey in Fukushima

    S. Mochizuki, J. Kataoka, L. Tagawa, Y. Iwamoto, H. Okochi, N. Katsumi, S. Kinno, M. Arimoto, T. Maruhashi, K. Fujieda, T. Kurihara, S. Ohsuka

    JOURNAL OF INSTRUMENTATION   12 ( 11 ) P11014  2017.11  [Refereed]

     View Summary

    Considerable amounts of radioactive substances (mainly Cs-137 and Cs-134) were released into the environment after the Japanese nuclear disaster in 2011. Some restrictions on residence areas were lifted in April 2017, owing to the successive and effective decontamination operations. However, the distribution of radioactive substances in vast areas of mountain, forest and satoyama close to the city is still unknown; thus, decontamination operations in such areas are being hampered. In this paper, we report on the first aerial gamma-ray imaging of a schoolyard in Fukushima using a drone that carries a high sensitivity Compton camera. We showthat the distribution of Cs-137 in regions with a diameter of several tens to a hundred meters can be imaged with a typical resolution of 2-5 m within a 10-20 min flights duration. The aerial gamma-ray images taken 10 m and 20 m above the ground are qualitatively consistent with a dose map reconstructed from the ground-based measurements using a survey meter. Although further quantification is needed for the distance and air-absorption corrections to derive in situ dose map, such an aerial drone system can reduce measurement time by a factor of ten and is suitable for place where ground-based measurement are difficult.

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    38
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  • Development of gamma-ray detector sensitive to source directions using GAGG(Ce) scintillators and MPPCs

    Keiki Kojima, Takeshi Nakamori, Daiki Nemoto, Shuichi Gunji, Hiroki Sato, Shigeki Ito, Sho Kato, Masao Yoshino, Yoshiyuki Usuki, Jun Kataoka

    2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop, NSS/MIC/RTSD 2016   2017-January  2017.10  [Refereed]

     View Summary

    © 2016 IEEE. We have developed a simpler, smaller, and thus less expensive gamma-ray detector that can roughly determine the incident direction of a radiation source with moderate angular resolution, aiming for personal use beyond that afforded by conventional survey meters. The detector consists of six GAGG(Ce) scintillators with dimensions of 20 × 20 × 6 mm3 on each face of a 3-cm cubic lead block. Signals from each scintillator are read by a 3 × 3 mm2 Hamamatsu MPPC. We then applied χ2 fit to the observed count number set in order to determine the incident direction and set our angular accuracy goal of 22.5°. Through simulation, we injected 662 keV gamma rays uniformly from in front of the detector. We found that the R90 is distributed from 6.0° to 18.3° in all 980 directions for one-minute exposure to a 137Cs source that gives 0.15 μSv/h. Furthermore, our detector achieved the targeted value under BG intensity of 0.25 μSv/h in the experiment.

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  • Shedding new light on the Crab with polarized X-rays

    M. Chauvin, H. -G. Floren, M. Friis, M. Jackson, T. Kamae, J. Kataoka, T. Kawano, M. Kiss, V. Mikhalev, T. Mizuno, N. Ohashi, T. Stana, H. Tajima, H. Takahashi, N. Uchida, M. Pearce

    SCIENTIFIC REPORTS   7 ( 1 ) 7816  2017.08  [Refereed]

     View Summary

    Strong magnetic fields, synchrotron emission, and Compton scattering are omnipresent in compact celestial X-ray sources. Emissions in the X-ray energy band are consequently expected to be linearly polarized. X-ray polarimetry provides a unique diagnostic to study the location and fundamental mechanisms behind emission processes. The polarization of emissions from a bright celestial X-ray source, the Crab, is reported here for the first time in the hard X-ray band (similar to 20-160 keV). The Crab is a complex system consisting of a central pulsar, a diffuse pulsar wind nebula, as well as structures in the inner nebula including a jet and torus. Measurements are made by a purpose-built and calibrated polarimeter, PoGO+. The polarization vector is found to be aligned with the spin axis of the pulsar for a polarization fraction, PF = (20.9 +/- 5.0)%. This is higher than that of the optical diffuse nebula, implying a more compact emission site, though not as compact as, e.g., the synchrotron knot. Contrary to measurements at higher energies, no significant temporal evolution of phase-integrated polarisation parameters is observed. The polarization parameters for the pulsar itself are measured for the first time in the X-ray energy band and are consistent with observations at optical wavelengths.

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  • Optimization and verification of image reconstruction for a Compton camera towards application as an on-line monitor for particle therapy

    T. Taya, J. Kataoka, A. Kishimoto, L. Tagawa, S. Mochizuki, T. Toshito, M. Kimura, Y. Nagao, K. Kurita, M. Yamaguchi, N. Kawachi

    JOURNAL OF INSTRUMENTATION   12 ( 7 ) P07015 - P07015  2017.07  [Refereed]

     View Summary

    Particle therapy is an advanced cancer therapy that uses a feature known as the Bragg peak, in which particle beams suddenly lose their energy near the end of their range. The Bragg peak enables particle beams to damage tumors effectively. To achieve precise therapy, the demand for accurate and quantitative imaging of the beam irradiation region or dosage during therapy has increased. The most common method of particle range verification is imaging of annihilation gamma rays by positron emission tomography. Not only 511-keV gamma rays but also prompt gamma rays are generated during therapy; therefore, the Compton camera is expected to be used as an on-line monitor for particle therapy, as it can image these gamma rays in real time. Proton therapy, one of the most common particle therapies, uses a proton beam of approximately 200 MeV, which has a range of similar to 25 cm in water. As gamma rays are emitted along the path of the proton beam, quantitative evaluation of the reconstructed images of diffuse sources becomes crucial, but it is far from being fully developed for Compton camera imaging at present. In this study, we first quantitatively evaluated reconstructed Compton camera images of uniformly distributed diffuse sources, and then confirmed that our Compton camera obtained 3 %(1 sigma) and 5 %(1 sigma) uniformity for line and plane sources, respectively. Based on this quantitative study, we demonstrated on-line gamma imaging during proton irradiation. Through these studies, we show that the Compton camera is suitable for future use as an on-line monitor for particle therapy.

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  • Novel photon-counting low-dose computed tomography using a multi-pixel photon counter

    H. Morita, T. Oshima, J. Kataoka, M. Arimoto, H. Nitta

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   857 ( 11 ) 58 - 65  2017.06  [Refereed]

     View Summary

    X-ray computed tomography (CT) is widely used in diagnostic imaging. Owing to a strong radiation exposure associated with this method, numerous proposals have been made for reducing the radiation dose. In addition, conventional CT does not provide information on the energy associated with each X-ray photon because intensity is rather high, typically amounts to 10(7-9) cps/mm(2). Here, we propose a novel, low-dose photon-counting CT system based on a multi-pixel photon counter (MPPC) and a high-speed scintillator. To demonstrate high signal-to-noise ratio utilizing the internal gain and the fast time response of the MPPC, we compared CT images acquired under the same conditions among a photodiode (PD), an avalanche photodiode and a MPPC. In particular, the images' contrast-to-noise ratio (CNR) acquired using the MPPC improved 12.6-fold compared with the images acquired in conventional CT using a PD. We also performed energy-resolved imaging by adopting 4 energy thresholds of 20, 40, 60, and 80 keV. We confirmed a substantial improvement of the imaging contrast as well as a reduction in the beam hardening for the CT images. We conclude that the proposed MPPC-based detector is likely to be a promising device for use in future CT scanners.

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    19
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  • Energy calibration of CALET onboard the International Space Station

    Y. Asaoka, Y. Akaike, Y. Komiya, R. Miyata, S. Torii, O. Adriani, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. Kitamura, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astroparticle Physics   91   1 - 10  2017.05  [Refereed]

     View Summary

    © 2017 The Authors In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement.

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  • First demonstration of multi-color 3-D in vivo imaging using ultra-compact Compton camera

    Aya Kishimoto, Jun Kataoka, Takanori Taya, Leo Tagawa, Saku Mochizuki, Shinji Ohsuka, Yuto Nagao, Keisuke Kurita, Mitsutaka Yamaguchi, Naoki Kawachi, Keiko Matsunaga, Hayato Ikeda, Eku Shimosegawa, Jun Hatazawa

    SCIENTIFIC REPORTS   7 ( 1 ) 2110  2017.05  [Refereed]

     View Summary

    In the field of nuclear medicine, single photon emission tomography and positron emission tomography are the two most common techniques in molecular imaging, but the available radioactive tracers have been limited either by energy range or difficulties in production and delivery. Thus, the use of a Compton camera, which features gamma-ray imaging of arbitrary energies from a few hundred keV to more than MeV, is eagerly awaited along with potential new tracers which have never been used in current modalities. In this paper, we developed an ultra-compact Compton camera that weighs only 580 g. The camera consists of fine-pixelized Ce-doped Gd3Al2Ga30O12 scintillators coupled with multi-pixel photon counter arrays. We first investigated the 3-D imaging capability of our camera system for a diffuse source of a planar geometry, and then conducted small animal imaging as pre-clinical evaluation. For the first time, we successfully carried out the 3-D color imaging of a live mouse in just 2 h. By using tri-color gamma-ray fusion images, we confirmed that I-131, Sr-85, and Zn-65 can be new tracers that concentrate in each target organ.

    DOI PubMed

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  • Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy Cluster

    F. A. Aharonian, H. Akamatsu, F. Akimoto, S. W. Allen, L. Angelini, K. A. Arnaud, M. Audard, H. Awaki, M. Axelsson, A. Bamba, M. W. Bautz, R. D. Blandford, E. Bulbul, L. W. Brenneman, G. V. Brown, E. M. Cackett, M. Chernyakova, M. P. Chiao, P. Coppi, E. Costantini, J. de Plaa, J. -W. den Herder, C. Done, T. Dotani, K. Ebisawa, M. E. Eckart, T. Enoto, Y. Ezoe, A. C. Fabian, C. Ferrigno, A. R. Foster, R. Fujimoto, Y. Fukazawa, A. Furuzawa, M. Galeazzi, L. C. Gallo, P. Gandhi, M. Giustini, A. Goldwurm, L. Gu, M. Guainazzi, Y. Haba, K. Hagino, K. Hamaguchi, I. Harrus, I. Hatsukade, K. Hayashi, T. Hayashi, K. Hayashida, J. Hiraga, A. E. Hornschemeier, A. Hoshino, J. P. Hughes, Y. Ichinohe, R. Iizuka, H. Inoue, S. Inoue, Y. Inoue, K. Ishibashi, M. Ishida, K. Ishikawa, Y. Ishisaki, M. Itoh, M. Iwai, N. Iyomoto, J. S. Kaastra, T. Kallman, T. Kamae, E. Kara, J. Kataoka, S. Katsuda, J. Katsuta, M. Kawaharada, N. Kawai, R. L. Kelley, D. Khangulyan, C. A. Kilbourne, A. L. King, T. Kitaguchi, S. Kitamoto, T. Kitayama, T. Kohmura, M. Kokubun, S. Koyama, K. Koyama, P. Kretschmar, H. A. Krimm, A. Kubota, H. Kunieda, P. Laurent, F. Lebrun, S. -H. Lee, M. A. Leutenegger, O. Limousin, M. Loewenstein, K. S. Long, D. H. Lumb, G. M. Madejski, Y. Maeda, D. Maier, K. Makishima, M. Markevitch, H. Matsumoto, K. Matsushita, D. McCammon, B. R. McNamara, M. Mehdipour, E. D. Miller, J. M. Miller, S. Mineshige, K. Mitsuda, I. Mitsuishi, T. Miyazawa, T. Mizuno, H. Mori, K. Mori, H. Moseley, K. Mukai, H. Murakami, T. Murakami, R. F. Mushotzky, T. Nakagawa, H. Nakajima, T. Nakamori, T. Nakano, S. Nakashima, K. Nakazawa, K. Nobukawa, M. Nobukawa, H. Noda, M. Nomachi, S. L. O'Dell, H. Odaka, T. Ohashi, M. Ohno, T. Okajima, N. Ota, M. Ozaki, F. Paerels, S. Paltani, A. Parmar, R. Petre, C. Pinto, M. Pohl, F. S. Porter, K. Pottschmidt, B. D. Ramsey, C. S. Reynolds, H. R. Russell, S. Safi-Harb, S. Saito, K. Sakai, H. Sameshima, T. Sasaki, G. Sato, K. Sato, R. Sato, M. Sawada, N. Schartel, P. J. Serlemitsos, H. Seta, M. Shidatsu, A. Simionescu, R. K. Smith, Y. Soong, L. Stawarz, Y. Sugawara, S. Sugita, A. E. Szymkowiak, H. Tajima, H. Takahashi, T. Takahashi, S. Takeda, Y. Takei, T. Tamagawa, K. Tamura, T. Tamura, T. Tanaka, Yasuo Tanaka, Yasuyuki Tanaka, M. Tashiro, Y. Tawara, Y. Terada, Y. Terashima, F. Tombesi, H. Tomida, Y. Tsuboi, M. Tsujimoto, H. Tsunemi, T. Tsuru, H. Uchida, H. Uchiyama, Y. Uchiyama, S. Ueda, Y. Ueda, S. Ueno, S. Uno, C. M. Urry, E. Ursino, C. P. de Vries, S. Watanabe, N. Werner, D. R. Wik, D. R. Wilkins, B. J. Williams, S. Yamada, H. Yamaguchi, K. Yamaoka, N. Y. Yamasaki, M. Yamauchi, S. Yamauchi, T. Yaqoob, Y. Yatsu, D. Yonetoku, A. Yoshida, I. Zhuravleva, A. Zoghbi

    ASTROPHYSICAL JOURNAL LETTERS   837 ( 1 ) 668 - 672  2017.03  [Refereed]

     View Summary

    X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E approximate to 3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of S XVI (E similar or equal to 3.44 keV rest-frame)-a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment.

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  • 福島県の里山に大気沈着した放射性Csの長期変動

    金野俊太郎, 大河内博, 勝見尚也, 緒方裕子, 片岡淳, 岸本彩, 岩本康弘, 反町篤行, 床次眞司

    分析化学会誌   66 ( 3 ) 17  2017.03  [Refereed]

  • Long-term Variations in the Distribution of Radioactive Cs in Plant, Soil, Stream Bottom Sand in a Small Forest in Fukushima Prefecture

    Kinno Shuntaro, Okochi Hiroshi, Katsumi Naoya, Ogata Hiroko, Kataoka Jun, Kishimoto Aya, Iwamoto Yasuhiro, Sorimachi Atsuyuki, Tokonami Shinji

    BUNSEKI KAGAKU   66 ( 3 ) 163 - 174  2017.03  [Refereed]

     View Summary

    Radio-Cs concentrations in fresh leaves/needles, litter, surface soil, and stream sand were continuously investigated in a deciduous broadleaf forest and cedar forest in Namie-town, Fukushima prefecture from June 2012 to June 2016, except for snow-cover periods. The result of a car-borne survey from Fukushima city to Minamitsushima showed that the air dose rate declined faster than the physical attenuation due to decontamination, outside of forests. Radio-Cs concentrations (137Cs +134Cs) in litter and surface soil in broadleaf forest were constant at 52.0, 102 kBq kg-dry–1, respectively from 2014. In a cedar forest, however, the radio-Cs concentrations in fresh needles and litter declined from 2012 to 2015, probably because of washing and leaching by throughfall, and radio-Cs was accumulated in surface soil. In broadleaf forest, the buffer depth of radio-Cs in soil (1.26 cm) which indicates the extent of infiltration into deeper layers was greater than in the cedar forest (1.14 cm) in April 2013. However, the buffer depth in the cedar forest overtook that in the broadleaf forest in December, 2015 (1.5 cm in broadleaf forest and 2.6 cm in cedar forest). The radio-Cs values in the stream bottom sand were concentrated in smaller sand (over 2 mm, 3.04; 0.21-2.0 mm, 10.2; under 0.21 mm, 54.5 kBq kg-dry–1 in downstream near the broadleaf forest and over 2.0 mm, 2.67, 0.21-2.0 mm, 7.95; under 0.21 mm, 41.3 kBq kg-dry–1 in the upstream area near the cedar forest). It is concerned that a part of them causes the outflow of radio-Cs as suspended sand. The relative radio-Cs concentration ratio between smaller bottom sand and surface soil, which indicates the outflow of radio-Cs from forest via stream declined (2013: 0.54, 2016: 0.29 in downstream and 2013: 1.4, 2016: 0.31 in the upstream region). However, we found that floating male flowers of cedar containing high radio-Cs (23.8 kBq kg-dry–1) could be another transport media in the spring.

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  • Development of TOF-PET using Compton scattering by plastic scintillators

    M. Kuramoto, T. Nakamori, S. Kimura, S. Gunji, M. Takakura, J. Kataoka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   845   668 - 672  2017.02  [Refereed]

     View Summary

    We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators. (C) 2016 Elsevier B.V. All rights reserved.

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  • Development of a compact scintillator-based high-resolution Compton camera for molecular imaging

    A. Kishimoto, J. Kataoka, A. Koide, K. Sueoka, Y. Iwamoto, T. Taya, S. Ohsuka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   845 ( 11 ) 656 - 659  2017.02  [Refereed]

     View Summary

    The Compton camera, which shows gamma-ray distribution utilizing the kinematics of Compton scattering, is a promising detector capable of imaging across a wide range of energy. In this study, we aim to construct a small-animal molecular imaging system in a wide energy range by using the Compton camera. We developed a compact medical Compton camera based on a Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillator and multi-pixel photon counter (MPPC). A basic performance confirmed that for 662 keV, the typical energy resolution was 7.4 % (FWHM) and the angular resolution was 4.5 degrees (FWHM). We then used the medical Compton camera to conduct imaging experiments based on a 3-D imaging reconstruction algorithm using the multi-angle data acquisition method. The result confirmed that for a Cs-137 point source at a distance of 4 cm, the image had a spatial resolution of 3.1 mm (FWHM). Furthermore, we succeeded in producing 3-D multi-color image of different simultaneous energy sources (Na-22 [511 keV], Cs-137 [662 keV], and Mn-54 [834 key]). (C) 2016 Elsevier B.V. All rights reserved.

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  • CTA Report 123: General Report

    Kubo Hidetoshi, Teshima Masahiro, Totani Tomonori, Asano Katsuaki, Asano Akira, Ioka Kunihito, Ishio Kazuma, Inada Tomohiro, Inoue Susumu, Inoue Tsuyoshi, Inoue Yoshiyuki, Inome Yusuke, Iwamura Yuki, Warren Donald, Uchiyama Yasunobu, Ohishi Michiko, Ohoka Hideyuki, Ohira Yutaka, Okazaki Nao, Okumura Akira, Orito Reiko, Kagaya Mika, Kakuwa Jun, Kataoka Jun, Katagiri Hideaki, Katsukura Daisuke, Katsuda Satoru, Kato Sho, Kamimoto Takumi, Kawanaka Norita, Kisaka Shota, Kimura Souichiro, Cui Xiaohong, Kushida Junko, Kumon Taku, Kuroda Hayato, Gunji Shuichi, Kohri Kazunori, Koyama Shu, Kong Albert K. H., Saito Takayuki, Sakaki Naoto, Sakurai Shunsuke, Sasai Yoshinori, Sano Hidetoshi, Sawada Makoto, Shibata Toru, Dzhatdoev Timur, Sunada Yuji, Sekizaki Haruhito, Takata Jumpei, Takahashi Keitaro, Takahashi Tomoya, Takahashi Hiromitsu, Takahashi Mitsunari, Tajima Hiroyasu, Tachihara Kengo, Tanaka Shuta, Tanaka Takaaki, Tanaka Manobu, Tanaka Yasuyuki, Taneda Yuuki, Tam Thomas P. H., Cheng K. S., Chikawa Michiyuki, Tsujimoto Shimpei, Tsuru Takeshi, Tian Wenwu, Terada Yukikatsu, Toma Kenji, Tokanai Fuyuki, Naito Tsuguya, Nakajima Daisuke, Nagataki Shigehiro, Nakamura Yuki, Nakamori Takeshi, Nakayama Kazunori, Nagayoshi Tsutomu, Nishijima Kyoshi, Nishiyama Gaku, Nozaki Seiya, Noda Koji, Barkov Maxim, Hadasch Daniela, Hayakawa Takahiro, Hayashi Katsuhiro, Hayashida Masaaki, Hara Satoshi, Bamba Aya, Hidaka Naoya, Hirako Joe, Hiroshima Nagisa, Hirotani Kouichi, Hui David C. Y., Ferrand Gilles, Fukazawa Yasushi, Fukami Satoshi, Fukui Yasuo, Fujita Yutaka, He Haoning, Majumdar Pratik, Mazin Daniel, Masuda Shu, Matsumoto Hironori, Miura Chika, Mizuno Tsunefumi, Muraishi Hiroshi, Murase Kohta, Mori Koji, Yanagita Shohei, Yamazaki Ryo, Yamamoto Tokonatsu, Yamamoto Hiroaki, Yoshiike Satoshi, Yoshikoshi Takanori, Yoshida Atsumasa, Yoshida Tatsuo, Ri Ken, Lee Shiu-Hang (Herman)

    Meeting Abstracts of the Physical Society of Japan   72.2   355 - 355  2017

    DOI CiNii

  • CTA Report 125:Status report for the construction of Focal Plane Instrument of LST-1

    Sakurai S., Orito R., Kataoka J., Katagiri H., Kimura S., Kushida J., Kubo H., Gunji S., Koyama S., Konno Y., Saito T., Ikeno M., Sawada M., Sunada Y., Takahashi M., Tanaka M., Tsujimoto S., Teshima M., Terada Y., Tokanai F., Nakajima D., Nakamori T., Inada T., Nagayoshi T., Nishijima K., Nishiyama G., Nozaki S., Hayashida M., Bamba A., Hirako J., Fukami S., Masuda S., Yamamoto T., Inome Y., Yoshida T., Hadasch D., Mazin D., the CTA-Japan consortium, Iwamura Y., Uchida T., Ohoka H., Okumura A., Okazaki N.

    Meeting Abstracts of the Physical Society of Japan   72 ( 0 ) 360 - 360  2017

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  • CTA Report 126 : Improvement and calibration of the focal plane detector for LST

    Sunada Y., Orito R., Kataoka J., Katagiri H., Kimura S., Kushida J., Kubo H., Gunji S., Koyama S., Konno Y., Saito T., Ikeno M., Sawada M., Sakurai S., Takahashi M., Tanaka M., Tsujimoto S., Teshima M., Terada Y., Tokanai F., Nakajima D., Nakamori T., Inada T., Nagayoshi T., Nishijima K., Nishiyama G., Nozaki S., Hayashida M., Bamba A., Hirako J., Fukami S., Masuda S., Yamamoto T., Inome Y., Yoshida T., Hadasch D., Mazin D., the CTA-Japan consortium, Iwamura Y., Uchida T., Ohoka H., Okumura A., Okazaki N.

    Meeting Abstracts of the Physical Society of Japan   72 ( 0 ) 361 - 361  2017

    DOI CiNii

  • Secondary-electron-bremsstrahlung imaging for proton therapy

    Yamaguchi Mitsutaka, Nagao Yuto, Ando Koki, Yamamoto Seiichi, Toshito Toshiyuki, Kataoka Jun, Kawachi Naoki

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   833   199-207 - 207  2016.10  [Refereed]

     View Summary

    A feasibility study on an imaging technique of a therapeutic proton-beam trajectory using a gamma camera by measuring secondary electron bremsstrahlung (SEB) was performed by means of Monte Carlo simulations and a beam-irradiation experiment. From the simulation and experimental results, it was found that a significant amount of SEB yield exists between the beam-injection surface and the range position along the beam axis and the beam trajectory is clearly imaged by the SEB yield. It is concluded that the SEB imaging is a promising technique for monitoring of therapeutic proton-beam trajectories.

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  • Development and verification of signal processing system of avalanche photo diode for the active shields onboard ASTRO-H

    M. Ohno, T. Kawano, I. Edahiro, H. Shirakawa, N. Ohashi, C. Okada, S. Habata, J. Katsuta, Y. Tanaka, H. Takahashi, T. Mizuno, Y. Fukazawa, H. Murakami, S. Kobayashi, K. Miyake, K. Ono, Y. Kato, Y. Furuta, Y. Murota, K. Okuda, Y. Wada, K. Nakazawa, T. Mimura, J. Kataoka, Y. Ichinohe, Y. Uchida, M. Katsuragawa, H. Yoneda, G. Sato, R. Sato, M. Kawaharada, A. Harayama, H. Odaka, K. Hayashi, M. Ohta, S. Watanabe, M. Kokubun, T. Takahashi, S. Takeda, M. Kinoshita, K. Yamaoka, H. Tajima, Y. Yatsu, H. Uchiyama, S. Saito, T. Yuasa, K. Makishima

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   831   410 - 414  2016.09

     View Summary

    The hard X-ray Imager and Soft Gamma-ray Detector onboard ASTRO-H demonstrate high sensitivity to hard X-ray (5–80 keV) and soft gamma-rays (60–600 keV), respectively. To reduce the background, both instruments are actively shielded by large, thick Bismuth Germanate scintillators. We have developed the signal processing system of the avalanche photodiode in the BGO active shields and have demonstrated its effectiveness after assembly in the flight model of the HXI/SGD sensor and after integration into the satellite. The energy threshold achieved is about 150 keV and anti-coincidence efficiency for cosmic-ray events is almost 100%. Installed in the BGO active shield, the developed signal processing system successfully reduces the room background level of the main detector.

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    6
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  • CALET UPPER LIMITS on X-RAY and GAMMA-RAY COUNTERPARTS of GW151226

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. Kitamura, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astrophysical Journal Letters   829 ( 1 )  2016.09

     View Summary

    © 2016. The American Astronomical Society. All rights reserved.. We present upper limits in the hard X-ray and gamma-ray bands at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) gravitational-wave event GW151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ∼1 GeV up to 10 TeV with a field of view of ∼2 sr. The CALET gamma-ray burst monitor (CGBM) views ∼3 sr and ∼2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW151226 sky localization probability in the 7 keV-1 MeV and 40 keV-20 MeV bands respectively. We place a 90% upper limit of 2 ×10-7 erg cm-2 s-1 in the 1-100 GeV band where CAL reaches 15% of the integrated LIGO probability (∼1.1 sr). The CGBM 7σ upper limits are 1.0 ×10-6 erg cm-2 s-1 (7-500 keV) and 1.8 ×10-6 erg cm-2 s-1 (50-1000 keV) for a 1 s exposure. Those upper limits correspond to the luminosity of 3-5 ×1049 erg s-1, which is significantly lower than typical short GRBs.

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  • The Si/CdTe semiconductor camera of the ASTRO-H Hard X-ray Imager (HXI)

    Goro Sato, Kouichi Hagino, Shin Watanabe, Kei Genba, Atsushi Harayama, Hironori Kanematsu, Jun Kataoka, Miho Katsuragawa, Madoka Kawaharada, Shogo Kobayashi, Motohide Kokubun, Yoshikatsu Kuroda, Kazuo Makishima, Kazunori Masukawa, Taketo Mimura, Katsuma Miyake, Hiroaki Murakami, Toshio Nakano, Kazuhiro Nakazawa, Hirofumi Noda, Hirokazu Odaka, Mitsunobu Onishi, Shinya Saito, Rie Sato, Tamotsu Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin'ichiro Takeda, Takayuki Yuasa

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   831   235 - 241  2016.09  [Refereed]

     View Summary

    The Hard X-ray Imager (HXI) is one of the instruments onboard the ASTRO-H mission [14 to be launched in early 2016. The HXI is the focal plane detector of the hard X-ray reflecting telescope that covers an energy range from 5 to 80 keV. It will execute observations of astronomical objects with a sensitivity for point sources as faint as 1/100,000 of the Crab nebula at &gt; 10 keV. The HXI camera - the imaging part of the HXI - is realized by a hybrid semiconductor detector system that consists of silicon (Si) and cadmium telluride (CdTe) semiconductor detectors. Here, we present the final design of the HXI camera and report on the development of the flight model. The camera is composed of four layers of Double-sided Silicon Strip Detectors (DSSDs) and one layer of CdTe Double -sided Strip Detector (CdTeDSD), each with an imaging area of 32 mm x 32 mm. The strip pitch of the Si and CdTe sensors is 250 pm, and the signals from all 1280 strips are processed by 40 Application Specified Integrated Circuits (ASICs) developed for the HXI. The five layers of sensors are vertically stacked with a 4 mm spacing to increase the detection efficiency. The thickness of the sensors is 0.5 mm for the Si, and 0.75 mm for the CdTe. In this configuration, soft X-ray photons will be absorbed in the Si part, while hard X-ray photons will go through the Si part and will be detected in the CdTe part. The design of the sensor trays, peripheral circuits, power connections, and readout schemes are also described. The flight models of the HXI camera have been manufactured, tested and installed in the HXI instrument and then on the satellite. (C) 2016 Elsevier B.V. All rights reserved.

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  • Performance evaluation of newly developed SrI2(Eu) scintillator

    M. Takabe, A. Kishimoto, J. Kataoka, S. Sakuragi, Y. Yamasaki

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   831 ( 21 ) 260 - 264  2016.09  [Refereed]

     View Summary

    The development of europium-doped strontium iodide (SrI2(Eu)) has attracted considerable attention, because of its excellent material properties as regards gamma -ray scintillator applications. These include its excellent energy resolution, high light output (&gt;80, 000 ph/MeV), and high effective atomic number (Z=49). Here we report on the performance of 0 1 in x 1 in SrI2(Eu) cylindrical crystals newly fabricated by Union Materials Inc. In this study, we measured the energy resolution and light output at 10 C temperature intervals between 40 and 40 degrees C, using an optically coupled 2 -in photomultiplier tube (PMT) (Super Bialkali, Hamamatsu). The SrI2(Eu) light output increased by 0.12%/degrees C as the temperature decreased. At 40 C, we obtained the optimal energy resolution recording 2.91 0.02% full width at half maximum (FWHM) for 662 keV gamma rays measured with 137Cs. For comparison, we also measured the same crystal using both a large-area (19 x 19 mm2) avalanche photodiode detector (APD) and 8 x 8 multi -pixel photon counter (MPPC) arrays of 3 x 3 mm2 pixels. The energy resolutions of 2.94 + 0.02%, 3.14 + 0.06% and 3.99 + 0.01% were obtained using PMT, APD, and MPPC, respectively, as measured at 20 degrees C. We also measured the inherent background of SrI2(Eu) in a cave composed of Cu Pb blocks with their thickness of 5-10 cm confirming that Srl2(Eu) has an extremely low inherent background radiation. In this study, we have shown that SrI2(Eu) is a promising scintillator that can be utilized for radiation measurements incorporating low-energy X-rays to high-energy gamma rays, and can thus be applied in various medical, industrial, and environmental treatment fields in the near future. (C) 2016 Elsevier B.V. All rights reserved.

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  • Novel methods for estimating 3D distributions of radioactive isotopes in materials

    Y. Iwamoto, J. Kataoka, A. Kishimoto, T. Nishiyama, T. Taya, H. Okochi, H. Ogata, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   831 ( 21 ) 295 - 300  2016.09  [Refereed]

     View Summary

    In recent years, various gamma-ray visualization techniques, or gamma cameras, have been proposed. These techniques are extremely effective for identifying "hot spots" or regions where radioactive isotopes are accumulated. Examples of such would be nuclear-disaster-affected areas such as Fukushima or the vicinity of nuclear reactors. However, the images acquired with a gamma camera do not include distance information between radioactive isotopes and the camera, and hence are "degenerated" in the direction of the isotopes. Moreover, depth information in the images is lost when the isotopes are embedded in materials, such as water, sand, and concrete. Here, we propose two methods of obtaining depth information of radioactive isotopes embedded in materials by comparing (1) their spectra and (2) images of incident gamma rays scattered by the materials and direct gamma rays. In the first method, the spectra of radioactive isotopes and the ratios of scattered to direct gamma rays are obtained. We verify experimentally that the ratio increases with increasing depth, as predicted by simulations. Although the method using energy spectra has been studied for a long time, an advantage of our method is the use of low-energy (50-150 keV) photons as scattered gamma rays. In the second method, the spatial extent of images obtained for direct and scattered gamma rays is compared. By performing detailed Monte Carlo simulations using Geant4, we verify that the spatial extent of the position where gamma rays are scattered increases with increasing depth. To demonstrate this, we are developing various gamma cameras to compare low-energy (scattered) gamma -ray images with fully photo -absorbed gamma -ray images. We also demonstrate that the 3D reconstruction of isotopes/hotspots is possible with our proposed methods. These methods have potential applications in the medical fields, and in severe environments such as the nuclear-disaster-affected areas in Fukushima. (C) 2016 Elsevier B.V. All rights reserved.

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  • First demonstration of real-time gamma imaging by using a handheld Compton camera for particle therapy

    T. Taya, J. Kataoka, A. Kishimoto, Y. Iwamoto, A. Koide, T. Nishio, S. Kabuki, T. Inaniwa

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   831 ( 21 ) 355 - 361  2016.09  [Refereed]

     View Summary

    The use of real-time gamma imaging for cancer treatment in particle therapy is expected to improve the accuracy of the treatment beam delivery. In this study, we demonstrated the imaging of gamma rays generated by the nuclear interactions during proton irradiation, using a handheld Compton camera (14 cm x 15 cm x 16 cm, 2.5 kg) based on scintillation detectors. The angular resolution of this Compton camera is similar to 8 degrees at full width at half maximum (FVVHM) for a 137Cs source. We measured the energy spectra of the gamma rays using a LaBr3(Ce) scintillator and photomultiplier tube, and using the handheld Compton camera, performed image reconstruction when using a 70 MeV proton beam to irradiate a water, Ca(OH)(2), and polymethyl methacrylate (PMMA) phantom. In the energy spectra of all three phantoms, we found an obvious peak at 511 keV, which was derived from annihilation gamma rays, and in the energy spectrum of the PMMA phantom, we found another peak at 718 keV, which contains some of the prompt gamma rays produced from 10B. Therefore, we evaluated the peak positions of the projection from the reconstructed images of the PMMA phantom. The differences between the peak positions and the Bragg peak position calculated using simulation are 7 mm + 2 mm and 3 mm + 8 mm, respectively. Although we could quickly acquire online gamma imaging of both of the energy ranges during proton irradiation, we cannot arrive at a clear conclusion that prompt gamma rays sufficiently trace the Bragg peak from these results because of the uncertainty given by the spatial resolution of the Compton camera. We will develop a high -resolution Compton camera in the near future for further study. (C) 2016 Elsevier B.V. All rights reserved.

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  • Compton cameras for visualization of radioactive isotopes

    J.Kataoka, S.Takeda, T.Takahashi

      出版中 ( 8 ) 289 - 299  2016.08  [Refereed]  [Invited]

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  • INVERSE COMPTON X-RAY EMISSION FROM TeV BLAZAR MRK 421 DURING A HISTORICAL LOW-FLUX STATE OBSERVED WITH NuSTAR

    Jun Kataoka, Lukasz Stawarz

    ASTROPHYSICAL JOURNAL   827 ( 1 ) 55  2016.08  [Refereed]

     View Summary

    We report on the detection of excess hard X-ray emission from the TeV BL Lac object Mrk 421 during the historical low-flux state of the source in 2013 January. Nuclear Spectroscopic Telescope Array observations were conducted four times between MJD 56294 and MJD 56312 with a total exposure of 80.9 ks. The source flux in the 3-40 keV range was nearly constant, except for MJD 56307 when the average flux level increased by a factor of three. Throughout the exposure, the X-ray spectra of Mrk 421 were well represented by a steep power-law model with a photon index of Gamma similar or equal to 3.1, although a significant excess was noted above 20 keV in the MJD 56302 data when the source was in its faintest state. Moreover, Mrk 421 was detected at more than the 4 sigma level in the 40-79 keV count maps for both MJD 56307 and MJD 56302 but not during the remaining two observations. The detected excess hard X-ray emission connects smoothly with the extrapolation of the high-energy gamma-ray continuum of the blazar constrained by Fermi-LAT during source quiescence. These findings indicate that while the overall X-ray spectrum of Mrk 421 is dominated by the highest-energy tail of the synchrotron continuum, the variable excess hard X-ray emission above 20 keV (on the timescale of a week) is related to the inverse Compton emission component. We discuss the resulting constraints on the variability and spectral properties of the low-energy segment of the electron energy distribution in the source.

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  • The quiescent intracluster medium in the core of the Perseus cluster

    Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall Bautz, Roger Blandford, Laura Brenneman, Gregory V. Brown, Esra Bulbul, Edward Cackett, Maria Chernyakova, Meng Chiao, Paolo Coppi, Elisa Costantini, Jelle De Plaa, Jan Willem Den Herder, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi Gallo, Poshak Gandhi, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko Hiraga, Ann Hornschemeier, Akio Hoshino, John Hughes, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Kazunori Ishibashi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masayuki Itoh, Naoko Iyomoto, Jelle Kaastra, Timothy Kallman, Tuneyoshi Kamae, Erin Kara, Jun Kataoka, Satoru Katsuda, Junichiro Katsuta, Madoka Kawaharada, Nobuyuki Kawai, Richard Kelley, Dmitry Khangulyan, Caroline Kilbourne, Ashley King, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Shu Koyama, Katsuji Koyama, Peter Kretschmar, Hans Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, François Lebrun, Shiu Hang Lee, Maurice Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Grzegorz Madejski, Yoshitomo Maeda, Daniel Maier, Kazuo Makishima, Maxim Markevitch

    Nature   535 ( 7610 ) 117 - 121  2016.07

     View Summary

    Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling - a process known as active galactic nucleus feedback. Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 ± 10 kilometres per second in the region 30-60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 ± 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure.

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  • Development of a high resolution gamma camera system using finely grooved GAGG scintillator

    Seiichi Yamamoto, Jun Kataoka, Tsubasa Oshima, Yoshimune Ogata, Tadashi Watabe, Hayato Ikeda, Yasukazu Kanai, Jun Hatazawa

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   821   28 - 33  2016.06  [Refereed]

     View Summary

    High resolution gamma cameras require small pixel scintillator blocks with high light output. However, manufacturing a small pixel scintillator block is difficult when the pixel size becomes small. To solve this limitation, we developed a high resolution gamma camera system using a finely grooved Ce-doped Gd3Al2Ga3O12 (GAGG) plate. Our gamma camera's detector consists of a 1-mm-thick finely grooved GAGG plate that is optically coupled to a 1-in. position sensitive photomultiplier tube (PSPMT). The grooved GAGG plate has 0.2 x 0.2 mm pixels with 0.05-mm wide slits (between the pixels) that were manufactured using a dicing saw. We used a Hamamatsu PSPMT with a 1-in. square high quantum efficiency (HQE) PSPMT (R8900-100-C12). The energy resolution for the Co-57 gamma photons (122 keV) was 18.5% FWHM. The intrinsic spatial resolution was estimated to be 0.7-mm FVVHM. With a 0.5-mm diameter pinhole collimator mounted to its front, we achieved a high resolution, small field-of-view gamma camera. The system spatial resolution for the Co-57 gamma photons was 1.0-mm FWHM, and the sensitivity was 0.0025%, 10 mm from the collimator surface. The Tc-99m HMDP administered mouse images showed the fine structures of the mouse body's parts. Our developed high resolution small pixel GAGG gamma camera is promising for such small animal imaging. (C) 2016 Elsevier B.V. All rights reserved.

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  • CO-to-H-2 conversion factor of molecular clouds using X-ray shadows

    Yoshiaki Sofue, Jun Kataoka

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   68 ( 3 ) L8  2016.06  [Refereed]

     View Summary

    A new method to determine the CO-to-H-2 conversion factor X-CO using absorption of diffuse X-ray emission by local molecular clouds was developed. It was applied to the Ophiuchus (G353+17) and Corona Australis (G359-18) clouds using CO line and soft X-ray archival data. We obtained a value X-CO = 1.85 +/- 0.45 x 10(20) H-2 cm(-2) (Kkms(-1))(-1) as the average of least-chi(2) fitting results for R4 (0.7 keV) and R5 (0.8 keV) bands.

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  • Galactic Centre hypershell model for the North Polar Spurs

    Y. Sofue, A. Habe, J. Kataoka, T. Totani, Y. Inoue, S. Nakashima, H. Matsui, M. Akita

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   459 ( 1 ) 108 - 120  2016.06  [Refereed]

     View Summary

    The bipolar-hypershell (BHS) model for the North Polar Spurs (NPS-E, -W, and Loop I) and counter southern spurs (SPS-E and -W) is revisited based on numerical hydrodynamical simulations. Propagations of shock waves produced by energetic explosive events in the Galactic Centre are examined. Distributions of soft X-ray brightness on the sky at 0.25, 0.7, and 1.5 keV in the +/- 50 degrees x +/- 50 degrees region around the Galactic Centre are modelled by thermal emission from high-temperature plasma in the shock-compressed shell considering shadowing by the interstellar H I and H-2 gases. The result is compared with the ROSAT wide field X-ray images in R2, 4, and 6 bands. The NPS and southern spurs are well reproduced by the simulation as shadowed dumbbell-shaped shock waves. We discuss the origin and energetics of the event in relation to the starburst and/or active galactic nucleus activities in the Galactic Centre.

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  • THE FIRST FERMI LAT SUPERNOVA REMNANT CATALOG

    F. Acero, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, R. Caputo, M. Caragiulo, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. M. Cohen, J. Cohen-Tanugi, L. R. Cominsky, B. Condon, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, E. C. Ferrara, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, M. H. Grondin, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, M. Hayashida, E. Hays, J. W. Hewitt, A. B. Hill, D. Horan, X. Hou, G. Iafrate, T. Jogler, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Katsuta, M. Kerr, J. Knödlseder, D. Kocevski, M. Kuss, H. Laffon, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, J. Li, L. Li, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, J. Magill, S. Maldera, M. Marelli, M. Mayer

    Astrophysical Journal, Supplement Series   224 ( 1 )  2016.05

     View Summary

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope (LAT). Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude allows us to determine an upper limit of 22% on the number of GeV candidates falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, we demonstrate the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. We model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays.

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  • Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder

    Chauvin M, Floren H. -G, Jackson M, Kamae T, Kawano T, Kiss M, Kole M, Mikhalev V, Moretti E, Olofsson G, Rydstrom S, Takahashi H, Iyudin A, Arimoto M, Fukazawa Y, Kataoka J, Kawai N, Mizuno T, Ryde F, Tajima H, Takahashi T, Pearce M

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   456 ( 1 ) L84 - L88  2016.02  [Refereed]

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  • 19pCA-10 Development of TOF-PET using Compton scattering by plastic scintillators

    Kuramoto M., Nakamori T., Kimura S., Gunji S., Takakura M., Onodera T., Kataoka J.

    Meeting Abstracts of the Physical Society of Japan   71   101 - 101  2016

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  • Initial in orbit performance of the Hard X-ray Imager onboard Hitomi X-ray satellite

    Nakazawa K., Takahashi T., Kokubun M., Watanabe S., Sato G., Ota M., Hagino K., Sato R., Lee Herman, Nomachi M., Yonetoku D., Tanaka T., Enoto T., Terada Y., Uchiyama H., Yatsu Y., Ichinohe Y., Noda H., Tajima H., Yamaoka K., Hayashi K., Fukazawa Y., Mizuno T., Ohno M., Takahashi H., Nakamori T., Uchiyama S., Saito S., Makishima K., Yuasa T., Nakano T., Kataoka J., Francois Lebrun, Andrea Goldwurm, Olivier Limousin, Philippe Laurent, Daniel Maier, Takeda Shinichiro, Odaka Hirokazu, the HXI team

    Meeting Abstracts of the Physical Society of Japan   71   370 - 370  2016

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  • In-orbit performance of Soft Gamma-ray Detector(SGD) onboard Hitomi (ASTRO-H) X-ray satellite

    Watanabe Shin, Tajima Hiroyasu, Fukazawa Yasushi, Ichinohe Yuto, Uchiyama Hideki, Uchiyama Yasunobu, Enoto Teruaki, Ohta Masayuki, Ohno Masanori, Odaka Hirokazu, Kataoka Jun, Katsuta Junichiro, Kitaguchi Takao, Kokubun Motohide, Goldwurm Andrea, Saito Shinya, Sato Goro, Sato Rie, Takahashi Tadayuki, Takahashi Hiromitsu, Takeda Shin'ichiro, Tanaka Takaaki, Tanaka Yasuyuki, Terada Yukikatsu, Nakazawa Kazuhiro, Nakano Toshio, Nakamori Takashi, Noda Hirofumi, Hagino Kouichi, Hayashi Katsuhiro, Blandford Roger, Makishima Kazuo, Madejski Grzegorz, Mizuno Tsunefumi, Mori Kunishiro, Yatsu Yoichi, Yamaoka Kazutaka, Yuasa Takayuki, Yonetoku Daisuke, Laurent Philippe, Limousin Olivier, Lebrun François, the SGD team

    Meeting Abstracts of the Physical Society of Japan   71   371 - 371  2016

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  • The ASTRO-H (Hitomi) X-ray astronomy satellite

    Tadayuki Takahashi, Motohide Kokubun, Kazuhisa Mitsuda, Richard Kelley, Takaya Ohashi, Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steve Allen, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Makoto Asai, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Philipp Azzarello, Chris Baluta, Aya Bamba, Nobutaka Bando, Marshall Bautz, Thomas Bialas, Roger Blandford, Kevin Boyce, Laura Brenneman, Greg Brown, Esra Bulbul, Edward Cackett, Edgar Canavan, Maria Chernyakova, Meng Chiao, Paolo Coppi, Elisa Costantini, Jelle De Plaa, Jan Willem Den Herder, Michael DiPirro, Chris Done, Tadayasu Dotani, John Doty, Ken Ebisawa, Megan Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew Fabian, Carlo Ferrigno, Adam Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi Gallo, Poshak Gandhi, Kirk Gilmore, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Daniel Haas, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Atsushi Harayama, Ilana Harrus, Isamu Hatsukade, Takayuki Hayashi, Katsuhiro Hayashi, Kiyoshi Hayashida, Junko Hiraga, Kazuyuki Hirose, Ann Hornschemeier, Akio Hoshino, John Hughes, Yuto Ichinohe, Ryo Iizuka, Yoshiyuki Inoue, Hajime Inoue, Kazunori Ishibashi, Manabu Ishida, Kumi Ishikawa, Kosei Ishimura, Yoshitaka Ishisaki, Masayuki Itoh, Naoko Iwata, Naoko Iyomoto, Chris Jewell, Jelle Kaastra, Timothy Kallman, Tuneyoshi Kamae, Erin Kara, Jun Kataoka, Satoru Katsuda, Junichiro Katsuta, Madoka Kawaharada, Nobuyuki Kawai, Taro Kawano, Shigeo Kawasaki, Dmitry Khangulyan, Caroline Kilbourne, Mark Kimball, Ashley King

    Proceedings of SPIE - The International Society for Optical Engineering   9905  2016

     View Summary

    The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

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  • The hard X-ray imager (HXI) onboard ASTRO-H

    Kazuhiro Nakazawa, Goro Sato, Motohide Kokubun, Teruaki Enoto, Yasushi Fukazawa, Kouichi Hagino, Atsushi Harayama, Katsuhiro Hayashi, Jun Kataoka, Junichiro Katsuta, Philippe Laurent, Francois Lebrung, Olivier Limousin, Kazuo Makishima, Tsunefumi Mizuno, Kunishiro Mori, Takeshi Nakamori, Toshio Nakano, Hirofumi Noda, Hirokazu Odaka, Masanori Ohno, Masayuki Ohta, Shinya Saito, Rie Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin'ichiro Takeda, Yukikatsu Terada, Hideki Uchiyama, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Yoichi Yatsu, Takayuki Yuasa

    SPACE TELESCOPES AND INSTRUMENTATION 2016: ULTRAVIOLET TO GAMMA RAY   9905  2016  [Refereed]

     View Summary

    Hitomi X-ray observatory launched in 17 February 2016 had a hard X-ray imaging spectroscopy system made of two hard X-ray imagers (HXIs) coupled with two hard X-ray telescopes (HXTs). With 12 m focal length, they provide fine (2' half-power diameter; HPD) imaging spectroscopy at 5 to 80 keV. The HXI main imagers are made of 4 layers of Si and a CdTe semiconductor double-sided strip detectors, stacked to enhance detection efficiency as well as to enable photon interaction-depth sensing. Active shield made of 9 BGO scintillators surrounds the imager to provide with low background. Following the deployment of the Extensible Optical Bench (EOB) on 28 February, the HXI was gradually turned on. Two imagers successfully started observation on 14 March, and was operational till the incident lead to Hitomo loss, on 26 March. All detector channels, 1280 ch of imager and 11 channel of active shields and others each, worked well and showed performance consistent with those seen on ground. From the first light observation of G21.5-0.9 and the following Crab observations, 5 80 keV energy coverage and good detection efficiency were confirmed. With blank sky observations, we checked our background level. In some geomagnetic region, strong background continuum, presumably caused by trapped electron with energy similar to 100 keV, is seen. But by cutting the high-background time-intervals, the background became significantly lower, typically with 1-3x10(-4) counts s(-1) keV(-1) cm(-2) (here cm(2) is shown with detector geometrical area). Above 30 keV, line and continuum emission originating from activation of CdTe was significantly seen, though the level of 1-4x10(-4) counts s(-1) keV(-1) cm(-2) is still comparable to those seen in NuSTAR. By comparing the effective area and background rate, preliminary analysis shows that the HXI had a statistical sensitivity similar to NuSTAR for point sources, and more than twice better for largely extended sources.

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  • 2FHL: THE SECOND CATALOG OF HARD FERMI-LAT SOURCES

    Ackermann, M, Ajello, M, Atwood, W. B, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Gonzalez, J. Becerra, Bellazzini, R, Bissaldi, E, Blandford, R. D, Bloom, E. D, Bonino, R, Bottacini, E, Brandt, T. J, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, G. A, Cameron, R. A, Caputo, R, Caragiulo, M, Caraveo, P. A, Cavazzuti, E, Cecchi, C, Charles, E, Chekhtman, A, Cheung, C. C, Chiang, J, Chiaro, G, Ciprini, S, Cohen, J. M, Cohen-Tanugi, J, Cominsky, L. R, Conrad, J, Cuoco, A, Cutini, S, D'Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Di Mauro, M, Di Venere, L, Dominguez, A, Drell, P. S, Favuzzi, C, Fegan, S. J, Ferrara, E. C, Focke, W. B, Fortin, P, Franckowiak, A, Fukazawa, Y, Funk, S, Furniss, A. K, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, I. A, Grondin, M. -H, Guillemot, L, Guiriec, S, Harding, A. K, Hays, E, Hewitt, J. W, Hill, A. B, Horan, D, Iafrate, G, Hartmann, Dieter, Jogler, T, Johannesson, G, Johnson, A. S, Kamae, T, Kataoka, J, Knoedlseder, J, Kuss, M, La Mura, G, Larsson, S, Latronico, L, Lemoine-Goumard, M, Li, J, Li, L, Longo, F, Loparco, F, Lott, B, Lovellette, M. N, Lubrano, P, Madejski, G. M, Maldera, S, Manfreda, A, Mayer, M, Mazziotta, M. N, Michelson, P. F, Mirabal, N, Mitthumsiri, W, Mizuno, T, Moiseev, A. A, Monzani, M. E, Morselli, A, Moskalenko, I. V, Murgia, S, Nuss, E, Ohsugi, T, Omodei, N, Orienti, M, Orlando, E, Ormes, J. F, Paneque, D, Perkins, J. S, Pesce-Rollins, M, Petrosian, V, Piron, F, Pivato, G, Porter, T. A, Raino, S, Rando, R, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Reposeur, T, Romani, R. W, Sanchez-Conde, M, Parkinson, P. M. Saz, Schmid, J, Schulz, A, Sgro, C, Siskind, E. J, Spada, F, Spandre, G, Spinelli, P, Suson, D. J, Tajima, H, Takahashi, H, Takahashi, M, Takahashi, T, Thayer, J. B, Thompson, D. J, Tibaldo, L, Torres, D. F, Tosti, G, Troja, E, Vianello, G, Wood, K. S, Wood, M, Yassine, M, Zaharijas, G, Zimmer, S

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   222 ( 1 )  2016.01  [Refereed]

     View Summary

    We present a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass. 8 event-level analysis allows the detection and characterization of sources in the 50 GeV-2 TeV energy range. In this energy band, Fermi-LAT. has detected 360 sources, which constitute the second catalog of hard Fermi-LAT. sources (2FHL). The improved angular resolution enables the precise localization of point sources (similar to 1.&#039; 7 radius at 68% C.L.) and the detection and characterization of spatially extended sources. We find that 86% of the sources can be associated with counterparts at other wavelengths, of which the majority (75%) are active galactic nuclei and the rest (11%) are Galactic sources. Only 25% of the 2FHL sources have been previously detected by Cherenkov telescopes, implying that the 2FHL provides a reservoir of candidates to be followed up at very high energies. This work closes the energy gap between the observations performed at GeV energies by Fermi-LAT. on orbit and the observations performed at higher energies by Cherenkov telescopes from the ground.

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  • The soft gamma-ray detector (SGD) onboard ASTRO-H

    Watanabe Shin, Tajima Hiroyasu, Fukazawa Yasushi, Blandford Roger, Enoto Teruaki, Goldwurm Andrea, Hagino Kouichi, Hayashi Katsuhiro, Ichinohe Yuto, Kataoka Jun, Katsuta Junichiro, Kitaguchi Takao, Kokubun Motohide, Laurent Philippe, Lebrun Francois, Limousin Olivier, Madejski Grzegorz M, Makishima Kazuo, Mizunoe Tsunefumi, Mori Kunishiro, Nakamori Takeshi, Nakano Toshio, Nakazawa Kazuhiro, Noda Hirofumi, Odaka Hirokazu, Ohno Masanori, Ohta Masayuki, Saito Shinya, Sato Goro, Sato Rie, Takeda Shin'ichiro, Takahashi Hiromitsu, Takahashi Tadayuki, Tanaka Takaaki, Tanaka Yasuyuki, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Yamaoka Kazutaka, Yatsu Yoichi, Yonetoku Daisuke, Yuasa Takayuki

    SPACE TELESCOPES AND INSTRUMENTATION 2016: ULTRAVIOLET TO GAMMA RAY   9905  2016  [Refereed]

     View Summary

    The Soft Gamma-ray Detector (SGD) is one of science instruments onboard ASTRO-H (Hitomi) and features a wide energy band of 60{600 keV with low backgrounds. SGD is an instrument with a novel concept of "Narrow field-of-view" Compton camera where Compton kinematics is utilized to reject backgrounds which are inconsistent with the field-of-view defined by the active shield. After several years of developments, the flight hardware was fabricated and subjected to subsystem tests and satellite system tests. After a successful ASTRO-H (Hitomi) launch on February 17, 2016 and a critical phase operation of satellite and SGD in-orbit commissioning, the SGD operation was moved to the nominal observation mode on March 24, 2016. The Compton cameras and BGO-APD shields of SGD worked properly as designed. On March 25, 2016, the Crab nebula observation was performed, and, the observation data was successfully obtained.

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  • Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder

    M. Chauvin, H. G. Florén, M. Jackson, T. Kamae, T. Kawano, M. Kiss, M. Kole, V. Mikhalev, E. Moretti, G. Olofsson, S. Rydström, H. Takahashi, A. Iyudin, M. Arimoto, Y. Fukazawa, J. Kataoka, N. Kawai, T. Mizuno, F. Ryde, H. Tajima, T. Takahashi, M. Pearce

    Monthly Notices of the Royal Astronomical Society: Letters   456 ( 1 ) L84 - L88  2016

     View Summary

    We have measured the linear polarization of hard X-ray emission from the Crab in a previously unexplored energy interval, 20-120 keV. The introduction of two new observational parameters, the polarization fraction and angle stands to disentangle geometrical and physical effects, thereby providing information on the pulsar wind geometry and magnetic field environment. Measurements are conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter. Polarization is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an anticoincidence well. The polarimetric response has been characterized prior to flight using both polarized and unpolarized calibration sources. We address possible systematic effects through observations of a background field. The measured polarization fraction for the integrated Crab light curve is 18.4+9.8 -10.6 per cent, corresponding to an upper limit (99 per cent credibility) of 42.4 per cent, for a polarization angle of (149.2 ± 16.0)°.

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  • Development of a high-precision color gamma-ray image sensor based on TSV-MPPC and diced scintillator arrays

    T. Oshima, J. Kataoka, A. Kishimoto, T. Fujita, Y. Kurei, T. Nishiyama, H. Morita, S. Yamamoto, K. Ogawa

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   803   8 - 14  2015.12  [Refereed]

     View Summary

    We developed a high precision color gamma ray image sensor with fine spatial resolution that is cost effective, widely applicable, and very sensitive, by using a diced Ce-doped Gd3Al2Ga3O12 (Ce:CACC.) scintillator array coupled with a 3.0 x 3.0 mm(2)/pixel 8 x 8 MPPC-array. The proposed image sensor can measure the energy of individual X-ray photons transmitted through an object. The pixel size of the Ce:GACC scintillator array is 02 mm, and the pixels are separated by 50-mu m-wide micro grooves, The image sensor has an area of 20 x 20 mm(2) and a thickness of 1.0 mm, and it achieves an excellent spatial resolution of 0.3-0.4 mm and energy resolutions of 12% and 18% (FVVHM) for 122 and 59.5 keV gamma rays, respectively. We conducted an experiment to determine the local effective atomic number of metals using dual energy gamma ray sources. In addition, we developed a color composite image using mixed images Laken at three energies (31, 59.5, and 88 keV). (C). 2015 Elsevier B.V. All rights reserved.

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    14
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  • Demonstration of three-dimensional imaging based on handheld Compton camera

    A. Kishimoto, J. Kataoka, T. Nishiyama, T. Taya, S. Kabuki

    JOURNAL OF INSTRUMENTATION   10 ( 11 )  2015.11  [Refereed]

     View Summary

    Compton cameras are potential detectors that are capable of performing measurements across a wide energy range for medical imaging applications, such as in nuclear medicine and ion beam therapy. In previous work, we developed a handheld Compton camera to identify environmental radiation hotspots. This camera consists of a 3D position-sensitive scintillator array and multi-pixel photon counter arrays. In this work, we reconstructed the 3D image of a source via list-mode maximum likelihood expectation maximization and demonstrated the imaging performance of the handheld Compton camera. Based on both the simulation and the experiments, we confirmed that multi-angle data acquisition of the imaging region significantly improved the spatial resolution of the reconstructed image in the direction vertical to the detector. The experimental spatial resolutions in the X, Y, and Z directions at the center of the imaging region were 6.81 mm +/- 0.13 mm, 6.52 mm +/- 0.07 mm and 6.71 mm +/- 0.11 mm (FWHM), respectively. Results of multi-angle data acquisition show the potential of reconstructing 3D source images.

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  • Demonstration of three-dimensional imaging based on handheld Compton camera

    A. Kishimoto, J. Kataoka, T. Nishiyama, T. Taya, S. Kabuki

    JOURNAL OF INSTRUMENTATION   10 ( 11 ) P11001  2015.11  [Refereed]

     View Summary

    Compton cameras are potential detectors that are capable of performing measurements across a wide energy range for medical imaging applications, such as in nuclear medicine and ion beam therapy. In previous work, we developed a handheld Compton camera to identify environmental radiation hotspots. This camera consists of a 3D position-sensitive scintillator array and multi-pixel photon counter arrays. In this work, we reconstructed the 3D image of a source via list-mode maximum likelihood expectation maximization and demonstrated the imaging performance of the handheld Compton camera. Based on both the simulation and the experiments, we confirmed that multi-angle data acquisition of the imaging region significantly improved the spatial resolution of the reconstructed image in the direction vertical to the detector. The experimental spatial resolutions in the X, Y, and Z directions at the center of the imaging region were 6.81 mm +/- 0.13 mm, 6.52 mm +/- 0.07 mm and 6.71 mm +/- 0.11 mm (FWHM), respectively. Results of multi-angle data acquisition show the potential of reconstructing 3D source images.

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    20
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  • FIRST NuSTAR OBSERVATIONS of MRK 501 WITHIN A RADIO to TeV MULTI-INSTRUMENT CAMPAIGN

    A. Furniss, K. Noda, S. Boggs, J. Chiang, F. Christensen, W. Craig, P. Giommi, C. Hailey, F. Harisson, G. Madejski, K. Nalewajko, M. Perri, D. Stern, M. Urry, F. Verrecchia, W. Zhang, M. L. Ahnen, S. Ansoldi, L. A. Antonelli, P. Antoranz, A. Babic, B. Banerjee, P. Bangale, U. Barres De Almeida, J. A. Barrio, J. Becerra González, W. Bednarek, E. Bernardini, B. Biasuzzi, A. Biland, O. Blanch, S. Bonnefoy, G. Bonnoli, F. Borracci, T. Bretz, E. Carmona, A. Carosi, A. Chatterjee, R. Clavero, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, P. Da Vela, F. Dazzi, A. De Angelis, G. De Caneva, B. De Lotto, E. De Oña Wilhelmi, C. Delgado Mendez, F. Di Pierro, D. Dominis Prester, D. Dorner, M. Doro, S. Einecke, D. Eisenacher Glawion, D. Elsaesser, A. Fernández-Barral, D. Fidalgo, M. V. Fonseca, L. Font, K. Frantzen, C. Fruck, D. Galindo, R. J. García López, M. Garczarczyk, D. Garrido Terrats, M. Gaug, P. Giammaria, N. Godinović, A. González Muñoz, D. Guberman, Y. Hanabata, M. Hayashida, J. Herrera, J. Hose, D. Hrupec, G. Hughes, W. Idec, H. Kellermann, K. Kodani, Y. Konno, H. Kubo, J. Kushida, A. La Barbera, D. Lelas, N. Lewandowska, E. Lindfors, S. Lombardi, F. Longo, M. López, R. López-Coto, A. López-Oramas, E. Lorenz, P. Majumdar, M. Makariev, K. Mallot, G. Maneva, M. Manganaro

    Astrophysical Journal   812 ( 1 )  2015.10

     View Summary

    We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsähovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission.

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  • THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE

    M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, R. J. Britto, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, B. Carpenter, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, R. D'Abrusco, F. D'Ammando, A. De Angelis, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, W. B. Focke, A. Franckowiak, L. Fuhrmann, Y. Fukazawa, A. K. Furniss, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, J. W. Hewitt, A. B. Hill, D. Horan, R. Itoh, G. Jóhannesson, A. S. Johnson, W. N. Johnson, J. Kataoka, T. Kawano, F. Krauss, M. Kuss, G. La Mura, S. Larsson, L. Latronico, C. Leto, J. Li, L. Li, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia

    Astrophysical Journal   810 ( 1 )  2015.09

     View Summary

    The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100 MeV and 300 GeV with a Test Statistic greater than 25, between 2008 August 4 and 2012 July 31. The 3LAC includes 1591 AGNs located at high Galactic latitudes (), a 71% increase over the second catalog based on 2 years of data. There are 28 duplicate associations, thus 1563 of the 2192 high-latitude gamma-ray sources of the 3FGL catalog are AGNs. Most of them (98%) are blazars. About half of the newly detected blazars are of unknown type, i.e., they lack spectroscopic information of sufficient quality to determine the strength of their emission lines. Based on their gamma-ray spectral properties, these sources are evenly split between flat-spectrum radio quasars (FSRQs) and BL Lacs. The most abundant detected BL Lacs are of the high-synchrotron-peaked (HSP) type. About 50% of the BL Lacs have no measured redshifts. A few new rare outliers (HSP-FSRQs and high-luminosity HSP BL Lacs) are reported. The general properties of the 3LAC sample confirm previous findings from earlier catalogs. The fraction of 3LAC blazars in the total population of blazars listed in BZCAT remains non-negligible even at the faint ends of the BZCAT-blazar radio, optical, and X-ray flux distributions, which hints that even the faintest known blazars could eventually shine in gamma-rays at LAT-detection levels. The energy-flux distributions of the different blazar populations are in good agreement with extrapolation from earlier catalogs.

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  • 25pSJ-5 Calibration Method for the Hard X-ray Imager On-board the ASTRO-H Satellite

    Mimura T, HXI team

    Meeting Abstracts of the Physical Society of Japan   70 ( 2 ) 353 - 353  2015.09

    DOI CiNii

  • The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, J. H. Buckley, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. Di Felice, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Journal of Physics: Conference Series   632 ( 1 )  2015.08

     View Summary

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

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  • Probing the precise location of the radio core in the TeV blazar Mrk 501 with VERA at 43 GHz

    Shoko Koyama, Motoki Kino, Akihiro Doi, Kotaro Niinuma, Kazuhiro Hada, Hiroshi Nagai, Mareki Honma, Kazunori Akiyama, Marcello Giroletti, Gabriele Giovannini, Monica Orienti, Naoki Isobe, Jun Kataoka, David Paneque, Hideyuki Kobayashi, Keiichi Asada

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   67 ( 4 )  2015.08  [Refereed]

     View Summary

    We investigate the position of the radio core in a blazar by multi-epoch astrometric observations at 43 GHz. Using the VLBI Exploration of Radio Astrometry (VERA), we have conducted four adjacent observations in 2011 February and another four in 2011 October, and succeeded in measuring the position of the radio core in the TeV blazar Mrk 501 relative to a distant compact quasar NRAO 512. During our observations, we find that (1) there is no positional change within similar to 0.2mas or similar to 2.0 pc de-projected with +/- 1 sigma s error for the weighted-mean phase-referenced positions of theMrk 501 core relative to NRAO 512 over four adjacent days, and (2) there is an indication of position change for the 3C 345 core relative to NRAO 512. By applying our results to the standard internal shock model for blazars, we constrain the bulk Lorenz factors of the ejecta.

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  • GLOBAL STRUCTURE OF ISOTHERMAL DIFFUSE X-RAY EMISSION ALONG THE FERMI BUBBLES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, Y. Inoue, S. Nakashima, C. C. Cheung

    ASTROPHYSICAL JOURNAL   807 ( 1 )  2015.07  [Refereed]

     View Summary

    In our previous works, we found absorbed thermal X-ray plasma with kT similar or equal to 0.3 keV observed ubiquitously near the edges of the Fermi bubbles and interpreted this emission as weakly shock-heated Galactic halo gas. Here we present a systematic and uniform analysis of archival Suzaku (29 pointings; 6 newly presented) and Swift (68 pointings; 49 newly presented) data within Galactic longitudes vertical bar l vertical bar &lt; 20 degrees and latitude 5 degrees less than or similar to vertical bar b vertical bar &lt; 60 degrees, covering the whole extent of the Fermi bubbles. We show that the plasma temperature is constant at kT similar or equal to 0.30 +/- 0.07 keV, while the emission measure (EM) varies by an order of magnitude, increasing toward the Galactic center (i.e., low vertical bar b vertical bar) with enhancements at the North Polar Spur (NPS), SE-claw, and NW-clump features. Moreover, the EM distribution of kT similar or equal to 0.30 keV plasma is highly asymmetric in the northern and southern bubbles. Although the association of the X-ray emission with the bubbles is not conclusive, we compare the observed EM properties with simple models assuming (i) a filled halo without bubbles, whose gas density follows a hydrostatic isothermal model (King profile), and (ii) a bubble-in-halo in which two identical bubbles expand into the halo, forming thick shells of swept halo gas. We argue that the EM profile in the north (b &gt; 0 degrees) favors (ii), whereas that of the south (b &lt; 0 degrees) is rather close to (i), but a weak excess signature is clearly detected also in the south like NPS (South Polar Spur). Such an asymmetry, if due to the bubbles, cannot be fully understood only by the inclination of bubbles' axis against the Galactic disk normal, thus suggesting asymmetric outflow due to different environmental/initial conditions.

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  • GLOBAL STRUCTURE OF ISOTHERMAL DIFFUSE X-RAY EMISSION ALONG THE FERMI BUBBLES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, Y. Inoue, S. Nakashima, C. C. Cheung

    ASTROPHYSICAL JOURNAL   807 ( 1 ) 77 - 89  2015.07  [Refereed]

     View Summary

    In our previous works, we found absorbed thermal X-ray plasma with kT similar or equal to 0.3 keV observed ubiquitously near the edges of the Fermi bubbles and interpreted this emission as weakly shock-heated Galactic halo gas. Here we present a systematic and uniform analysis of archival Suzaku (29 pointings; 6 newly presented) and Swift (68 pointings; 49 newly presented) data within Galactic longitudes vertical bar l vertical bar &lt; 20 degrees and latitude 5 degrees less than or similar to vertical bar b vertical bar &lt; 60 degrees, covering the whole extent of the Fermi bubbles. We show that the plasma temperature is constant at kT similar or equal to 0.30 +/- 0.07 keV, while the emission measure (EM) varies by an order of magnitude, increasing toward the Galactic center (i.e., low vertical bar b vertical bar) with enhancements at the North Polar Spur (NPS), SE-claw, and NW-clump features. Moreover, the EM distribution of kT similar or equal to 0.30 keV plasma is highly asymmetric in the northern and southern bubbles. Although the association of the X-ray emission with the bubbles is not conclusive, we compare the observed EM properties with simple models assuming (i) a filled halo without bubbles, whose gas density follows a hydrostatic isothermal model (King profile), and (ii) a bubble-in-halo in which two identical bubbles expand into the halo, forming thick shells of swept halo gas. We argue that the EM profile in the north (b &gt; 0 degrees) favors (ii), whereas that of the south (b &lt; 0 degrees) is rather close to (i), but a weak excess signature is clearly detected also in the south like NPS (South Polar Spur). Such an asymmetry, if due to the bubbles, cannot be fully understood only by the inclination of bubbles' axis against the Galactic disk normal, thus suggesting asymmetric outflow due to different environmental/initial conditions.

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  • FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG

    F. Acero, M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, A. Belfiore, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, J. R. Bogart, R. Bonino, E. Bottacini, J. Bregeon, R. J. Britto, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, R. Caputo, M. Caragiulo, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, E. Charles, R. C.G. Chaves, A. Chekhtman, C. C. Cheung, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, M. Deklotz, F. De Palma, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A. K. Harding, E. Hays, J. W. Hewitt, A. B. Hill, D. Horan, G. Iafrate, T. Jogler, G. Jóhannesson, R. P. Johnson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, J. Kataoka, J. Katsuta, M. Kuss, G. La Mura, D. Landriu, S. Larsson, L. Latronico, M. Lemoine-Goumard, J. Li, L. Li, F. Longo

    Astrophysical Journal, Supplement Series   218 ( 2 )  2015.06

     View Summary

    We present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in the 100 MeV-300 GeV range. Based on the first 4 yr of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the Second Fermi LAT catalog, the 3FGL catalog incorporates twice as much data, as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse γ-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources above significance, with source location regions, spectral properties, and monthly light curves for each. Of these, 78 are flagged as potentially being due to imperfections in the model for Galactic diffuse emission. Twenty-five sources are modeled explicitly as spatially extended, and overall 238 sources are considered as identified based on angular extent or correlated variability (periodic or otherwise) observed at other wavelengths. For 1010 sources we have not found plausible counterparts at other wavelengths. More than 1100 of the identified or associated sources are active galaxies of the blazar class; several other classes of non-blazar active galaxies are also represented in the 3FGL. Pulsars represent the largest Galactic source class. From source counts of Galactic sources we estimate that the contribution of unresolved sources to the Galactic diffuse emission is ∼3% at 1 GeV.

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    1371
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  • Erratum: THe second catalog of active galactic nuclei detected by the fermi large area telescope (Astrophysical Journal (2011) 743 (171))

    M. Ackermann, M. Ajello, A. Allafort, E. Antolini, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, L. Escande, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, S. E. Healey, D. Horan, X. Hou, R. E. Hughes, G. Iafrate, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. N. Mazziotta, W. McConville

    Astrophysical Journal   806 ( 1 )  2015.06

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  • Metal enrichment in the Fermi bubbles as a probe of their origin

    Yoshiyuki Inoue, Shinya Nakashima, Masaya Tahara, Jun Kataoka, Tomonori Totani, Yutaka Fujita, Yoshiaki Sofue

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   67 ( 3 )  2015.06  [Refereed]

     View Summary

    The Fermi bubbles are gigantic gamma-ray structures in our Galaxy. The physical origin of the bubbles is still under debate. The leading scenarios can be divided into two categories. One is nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, we propose that metal abundance measurements will provide an important clue to probe their origin. Based on a simple spherically symmetric bubble model, we find that the generated metallicity and abundance patterns of the bubbles' gas strongly depend on assumed star formation or AGN activities. Star formation scenarios predict higher metallicities and abundance ratios of [O/Fe] and [Ne/Fe] than AGN scenarios do because of supernovae ejecta. Furthermore, the resultant abundance depends on the gamma-ray emission process because different mass injection histories are required for the different gamma-ray emission processes due to the acceleration and cooling time scales of non-thermal particles. Future X-ray missions such as ASTRO-H and Athena will give a clue to probe the origin of the bubbles through abundance measurements with their high energy resolution instruments.

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    9
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  • Recent progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging

    J. Kataoka, A. Kishimoto, T. Fujita, T. Nishiyama, Y. Kurei, T. Tsujikawa, T. Oshima, T. Taya, Y. Iwamoto, H. Ogata, H. Okochi, S. Ohsuka, H. Ikeda, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   784   248 - 254  2015.06  [Refereed]

     View Summary

    The multi-pixel photon counter (MPPC) is a promising light sensor for various applications, not only in physics experiments but also in nuclear medicine, industry, and even high-energy astrophysics. In this paper, we present the current status and most recent progress of the MPPC-based scintillation detectors, such as (1) a high-precision X-ray and gamma-ray spectral image sensor, (2) next-generation PET detectors with MRI, TOF, and DOI measurement capabilities, and (3) a compact gamma camera for environmental radiation surveys. We first present a new method of fabricating a Ce:GAGG scintillator plate (1 or 2 mm thick) with ultra-fine resolution (0.2 mm/pixel), cut using a dicing saw to create 50 mu m wide micro-grooves. When the plate is optically coupled with a large-area MPPC array, excellent spatial resolution of 0.48 mm (FWHM) and energy resolution of 14% (FWHM) are obtained for 122 keV gamma rays. Hence, the detector can act as a convenient "multi-color" imaging device that can potentially be used for future SPECT and photon-counting CT. We then show a prototype system for a high-resolution MPPC-based PET scanner that can realize similar or equal to 1 mm (FWHM) spatial resolution, even under a strong magnetic field of 4.7 T. We develop a front-end ASIC intended for future TOF-PET scanner with a 16-channel readout that achieves a coincidence time resolution of 489 ps (FWHM). A novel design for a module with DOI-measurement capability for gamma rays is also presented by measuring the pulse height ratio of double-sided MPPCs coupled at both ends of scintillation crystal block. Finally, we present the concept of a two-plane Compton camera consisting of Ce:GAGG scintillator arrays coupled with thin MPPC arrays. As a result of the thin and compact features of the MPPC device, the camera not only achieves a small size (14 x 14 x 15 cm(3)) and light weight (1.9 kg) but also excellent sensitivity, compared to the conventional PMT-based pinhole camera used in Fukushima. Finally, we briefly describe a new product recently developed in conjunction with Hamamatsu Photonics K.K. that offers improved sensitivity and angular resolution of Delta theta similar to 8 degrees (FWHM) at 662 key, by incorporating DOI-segmented scintillator arrays. (C) 2014 Elsevier B.V. All rights reserved.

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    55
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  • Recent progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging

    J. Kataoka, A. Kishimoto, T. Fujita, T. Nishiyama, Y. Kurei, T. Tsujikawa, T. Oshima, T. Taya, Y. Iwamoto, H. Ogata, H. Okochi, S. Ohsuka, H. Ikeda, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   784   248 - 254  2015.06  [Refereed]

     View Summary

    The multi-pixel photon counter (MPPC) is a promising light sensor for various applications, not only in physics experiments but also in nuclear medicine, industry, and even high-energy astrophysics. In this paper, we present the current status and most recent progress of the MPPC-based scintillation detectors, such as (1) a high-precision X-ray and gamma-ray spectral image sensor, (2) next-generation PET detectors with MRI, TOF, and DOI measurement capabilities, and (3) a compact gamma camera for environmental radiation surveys. We first present a new method of fabricating a Ce:GAGG scintillator plate (1 or 2 mm thick) with ultra-fine resolution (0.2 mm/pixel), cut using a dicing saw to create 50 mu m wide micro-grooves. When the plate is optically coupled with a large-area MPPC array, excellent spatial resolution of 0.48 mm (FWHM) and energy resolution of 14% (FWHM) are obtained for 122 keV gamma rays. Hence, the detector can act as a convenient "multi-color" imaging device that can potentially be used for future SPECT and photon-counting CT. We then show a prototype system for a high-resolution MPPC-based PET scanner that can realize similar or equal to 1 mm (FWHM) spatial resolution, even under a strong magnetic field of 4.7 T. We develop a front-end ASIC intended for future TOF-PET scanner with a 16-channel readout that achieves a coincidence time resolution of 489 ps (FWHM). A novel design for a module with DOI-measurement capability for gamma rays is also presented by measuring the pulse height ratio of double-sided MPPCs coupled at both ends of scintillation crystal block. Finally, we present the concept of a two-plane Compton camera consisting of Ce:GAGG scintillator arrays coupled with thin MPPC arrays. As a result of the thin and compact features of the MPPC device, the camera not only achieves a small size (14 x 14 x 15 cm(3)) and light weight (1.9 kg) but also excellent sensitivity, compared to the conventional PMT-based pinhole camera used in Fukushima. Finally, we briefly describe a new product recently developed in conjunction with Hamamatsu Photonics K.K. that offers improved sensitivity and angular resolution of Delta theta similar to 8 degrees (FWHM) at 662 key, by incorporating DOI-segmented scintillator arrays. (C) 2014 Elsevier B.V. All rights reserved.

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    55
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  • The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, J. H. Buckley, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. Di Felice, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    EPJ Web of Conferences   95  2015.05

     View Summary

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

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    1
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  • MULTI-WAVELENGTH OBSERVATIONS OF THE BLACK WIDOW PULSAR 2FGL J2339.6-0532 WITH OISTER AND SUZAKU

    Yoichi Yatsu, Jun Kataoka, Yosuke Takahashi, Yutaro Tachibana, Nobuyuki Kawai, Shimpei Shibata, Sean Pike, Taketoshi Yoshii, Makoto Arimoto, Yoshihiko Saito, Takeshi Nakamori, Kazuhiro Sekiguchi, Daisuke Kuroda, Kenshi Yanagisawa, Hidekazu Hanayama, Makoto Watanabe, Ko Hamamoto, Hikaru Nakao, Akihito Ozaki, Kentaro Motohara, Masahiro Konishi, Ken Tateuchi, Noriyuki Matsunaga, Tomoki Morokuma, Takahiro Nagayama, Katsuhiro Murata, Hiroshi Akitaya, Michitoshi Yoshida, Gamal B. Ali, A. Essam Mohamed, Mizuki Isogai, Akira Arai, Hidenori Takahashi, Osamu Hashimoto, Ryo Miyanoshita, Toshihiro Omodaka, Jun Takahashi, Noritaka Tokimasa, Kentaro Matsuda, Shin-Ichiro Okumura, Kota Nishiyama, Seitaro Urakawa, Daisaku Nogami, Yumiko Oasa

    ASTROPHYSICAL JOURNAL   802 ( 2 )  2015.04

     View Summary

    Multi-wavelength observations of the black widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black widow in which a recycled millisecond pulsar (MSP) is evaporating the companion star with its powerful pulsar wind. Our optical observations show clear sinusoidal light curves due to the asymmetric temperature distribution of the companion star. Assuming a simple geometry, we constrained the range of the inclination angle of the binary system to 52 degrees &lt; i &lt; 59 degrees, which enables us to discuss the interaction between the pulsar wind and the companion in detail. The X-ray spectrum consists of two components: a soft, steady component that seems to originate from the surface of the MSP, and a hard, variable component from the wind-termination shock near the companion star. The measured X-ray luminosity is comparable to the bolometric luminosity of the companion, meaning that the heating efficiency is less than 0.5. In the companion orbit, 10(11) cm from the pulsar, the pulsar wind is already in the particle-dominant stage with a magnetization parameter of sigma &lt; 0.1. In addition, we precisely investigated the time variations of the X-ray periodograms and detected a weakening of the orbital modulation. The observed phenomenon may be related to unstable pulsar wind activity or weak mass accretion, both of which can result in the temporal extinction of the radio pulse.

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    9
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  • MULTI-WAVELENGTH OBSERVATIONS OF THE BLACK WIDOW PULSAR 2FGL J2339.6-0532 WITH OISTER AND SUZAKU

    Yoichi Yatsu, Jun Kataoka, Yosuke Takahashi, Yutaro Tachibana, Nobuyuki Kawai, Shimpei Shibata, Sean Pike, Taketoshi Yoshii, Makoto Arimoto, Yoshihiko Saito, Takeshi Nakamori, Kazuhiro Sekiguchi, Daisuke Kuroda, Kenshi Yanagisawa, Hidekazu Hanayama, Makoto Watanabe, Ko Hamamoto, Hikaru Nakao, Akihito Ozaki, Kentaro Motohara, Masahiro Konishi, Ken Tateuchi, Noriyuki Matsunaga, Tomoki Morokuma, Takahiro Nagayama, Katsuhiro Murata, Hiroshi Akitaya, Michitoshi Yoshida, Gamal B. Ali, A. Essam Mohamed, Mizuki Isogai, Akira Arai, Hidenori Takahashi, Osamu Hashimoto, Ryo Miyanoshita, Toshihiro Omodaka, Jun Takahashi, Noritaka Tokimasa, Kentaro Matsuda, Shin-Ichiro Okumura, Kota Nishiyama, Seitaro Urakawa, Daisaku Nogami, Yumiko Oasa

    ASTROPHYSICAL JOURNAL   802 ( 2 ) 84  2015.04  [Refereed]

     View Summary

    Multi-wavelength observations of the black widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black widow in which a recycled millisecond pulsar (MSP) is evaporating the companion star with its powerful pulsar wind. Our optical observations show clear sinusoidal light curves due to the asymmetric temperature distribution of the companion star. Assuming a simple geometry, we constrained the range of the inclination angle of the binary system to 52 degrees &lt; i &lt; 59 degrees, which enables us to discuss the interaction between the pulsar wind and the companion in detail. The X-ray spectrum consists of two components: a soft, steady component that seems to originate from the surface of the MSP, and a hard, variable component from the wind-termination shock near the companion star. The measured X-ray luminosity is comparable to the bolometric luminosity of the companion, meaning that the heating efficiency is less than 0.5. In the companion orbit, 10(11) cm from the pulsar, the pulsar wind is already in the particle-dominant stage with a magnetization parameter of sigma &lt; 0.1. In addition, we precisely investigated the time variations of the X-ray periodograms and detected a weakening of the orbital modulation. The observed phenomenon may be related to unstable pulsar wind activity or weak mass accretion, both of which can result in the temporal extinction of the radio pulse.

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    9
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  • SUZAKU X-RAY OBSERVATIONS OF THE FERMI BUBBLES: NORTHERNMOST CAP AND SOUTHEAST CLAW DISCOVERED WITH MAXI-SSC

    M. Tahara, J. Kataoka, Y. Takeuchi, T. Totani, Y. Sofue, J. S. Hiraga, H. Tsunemi, Y. Inoue, M. Kimura, C. C. Cheung, S. Nakashima

    ASTROPHYSICAL JOURNAL   802 ( 2 ) 91  2015.04  [Refereed]

     View Summary

    We report on Suzaku observations of large-scale X-ray structures possibly related to the Fermi Bubbles obtained in 2013 with a total duration of similar or equal to 80 ks. The observed regions were (1) the northern cap (N-cap; l similar to 0 degrees, 45 degrees&lt;b&lt; 55 degrees) seen in the mid-band (1.7-4.0 keV) map recently provided by Monitor of All-sky X-ray Image Solid-state Slit Camera (MAXI-SSC) and (2) the southeast claw (SE-claw; l similar to 10 degrees, -20 degrees &lt; b &lt; -10 degrees) seen in the ROSAT all-sky map and MAXI-SSC low-band (0.7-1.7 keV) map. In each region, we detected diffuse X-ray emission, which is represented by a three-component plasma model consisting of an unabsorbed thermal component (kT similar or equal to 0.1 keV) from the Local Hot Bubble, absorbed kT = 0.30 +/- 0.05 keV emission representing the Galactic halo (GH), and a power-law component due to the isotropic cosmic X-ray background radiation. The emission measure of the GH component in the SE-claw shows an excess by a factor of similar or equal to 2.5 over the surrounding emission at 2 degrees away. We also found a broad excess in the 1.7-4.0 keV count rates across the N-cap after compiling other archival data from Suzaku and Swift. The spectral stacking analysis of the N-cap data indicates the presence of another thermal component with kT = 0.70(-0.11)(+0.22)keV. The temperature kT similar or equal to 0.3 keV of the GH is higher than the ubiquitous value of kT similar or equal to 0.2 keV near the Fermi bubbles, and can be even higher (similar to 0.7 keV). We discuss our findings in the context of the bubble-halo interaction.

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  • MULTI-WAVELENGTH OBSERVATIONS OF THE BLACK WIDOW PULSAR 2FGL J2339.6-0532 WITH OISTER AND SUZAKU

    Yatsu, Y, Kataoka, J, Takahashi, Y, Tachibana, Y, Kawai, N, Shibata, S, Pike, S, Yoshii, T, Arimoto, M, Saito, Y, Nakamori, T, Sekiguchi, K, Kuroda, D, Yanagisawa, K, Hanayama, H, Watanabe, M, Hamamoto, K, Nakao, H, Ozaki, A, Motohara, K, Konishi, M, Tateuchi, K, Matsunaga, N, Morokuma, T, Nagayama, T, Murata, K, Akitaya, H, Yoshida, M, Ali, G. B, Essam Mohamed, A, Isogai, M, Arai, A, Takahashi, H, Hashimoto, O, Miyanoshita, R, Omodaka, T, Takahashi, J, Tokimasa, N, Matsuda, K, Okumura, S.-i, Nishiyama, K, Urakawa, S, Nogami, D, Oasa, Y, OISTER Team

    The Astrophysical Journal   802   84  2015.03  [Refereed]

    DOI

  • Six Years of Fermi-LAT and Multi-Wavelength Monitoring of the Broad-Line Radio Galaxy 3c 120: Jet Dissipation At Sub-Parsec Scales from the Central Engine

    Tanaka Y.~T, Doi A, Inoue Y, Cheung C.~C, Stawarz L, Fukazawa Y, Gurwell M.~A, Tahara M, Kataoka J, Itoh R

    The Astrophysical Journal Letters   799 ( 2 ) L18 - 6  2015.02  [Refereed]

     View Summary

    We present multi-wavelength monitoring results for the broad-line radio galaxy 3C 120 in the MeV/GeV, sub-millimeter, and 43 GHz bands over 6 yr. Over the past 2 yr, the Fermi-Large Area Telescope sporadically detected 3C 120 with high significance and the 230 GHz data also suggest an enhanced activity of the source. After the MeV/GeV detection from 3C 120 in MJD 56240-56300, 43 GHz Very Long Baseline Array (VLBA) monitoring revealed a brightening of the radio core, followed by the ejection of a superluminal knot. Since we observed the γ-ray and VLBA phenomena in temporal proximity to each other, it is naturally assumed that they are physically connected. This assumption was further supported by the subsequent observation that the 43 GHz core brightened again after a γ-ray flare occurred around MJD 56560. We can then infer that the MeV/GeV emission took place inside an unresolved 43 GHz core of 3C 120 and that the jet dissipation occurred at sub-parsec distances from the central black hole (BH), if we take the distance of the 43 GHz core from the central BH as ∼0.5 pc, as previously estimated from the time lag between X-ray dips and knot ejections. Based on our constraints on the relative locations of the emission regions and energetic arguments, we conclude that the γ rays are more favorably produced via the synchrotron self-Compton process, rather than inverse Compton scattering of external photons coming from the broad line region or hot dusty torus. We also derived the electron distribution and magnetic field by modeling the simultaneous broadband spectrum.

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  • The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV

    M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, C. Favuzzi, E. C. Ferrara, W. B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, K. Hayashi, E. Hays, J. W. Hewitt, P. Ippoliti, T. Jogler, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, J. Kataoka, J. Knödlseder, M. Kuss, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Manfreda, F. Massaro, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, R. Nemmen, E. Nuss, T. Ohsugi

    Astrophysical Journal   799 ( 1 )  2015.01

     View Summary

    The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse γ-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi ) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission (DGE), and a longer data accumulation of 50 months allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 ± 0.02 and a break energy of (279 ± 52) GeV using our baseline DGE model. The total intensity attributed to the IGRB is (7.2 ± 0.6) x 10-6 cm-2 s-1 sr-1 above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds.

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  • 27pSJ-1 CTA Report 96 : General Report on the CTA Project

    Teshima M., Tan Dang Viet, Hadasch Daniela, Mazin Daniel, CTA Japan Collaboration

    Meeting Abstracts of the Physical Society of Japan   70   390 - 390  2015

    DOI CiNii

  • 25pSJ-3 Results of ight integration test for Soft Gamma-ray Detector on board ASTRO-H

    Hayashi K., Blandford Roger, Madejski Grzegorz, Laurent Philippe, Limousin Olivier, Lebrun Francois, SGD team

    Meeting Abstracts of the Physical Society of Japan   70   351 - 351  2015

    DOI CiNii

  • 24aDJ-3 Balloon-borne Polarized Gamma-ray Observer : PoGOLite, Toward the 2nd flight in 2016

    Takahashi H., Pearce M., Chauvin M., Kiss M., Kole M., Mikhalev V., Moretti E., PoGOLino team

    Meeting Abstracts of the Physical Society of Japan   70   495 - 495  2015

    DOI CiNii

  • 23pDK-3 Test results of flight models for Soft Gamma-ray Detector on board ASTRO-H

    Tajima Hiroyasu, Blandford Roger, Madejski Grzegorz, Laurent Philippe, Limousin Olivier, Lebrun Francois, SGD team

    Meeting Abstracts of the Physical Society of Japan   70   470 - 470  2015

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  • 21pDD-12 Six Years of Fermi-LAT and Multi-wavelength Monitoring of the Broad-Line Radio Galaxy 3C 120: Jet Dissipation at Sub-parsec Scales from the Central Engine

    Tanaka Y. T., Doi A., Inoue Y., Cheung C. C., Stawarz L., Fukazawa Y., Gurwell M. A., Tahara M., Kataoka J., Itoh R.

    Meeting Abstracts of the Physical Society of Japan   70   416 - 416  2015

    DOI CiNii

  • 23pCF-13 Development of a high-precision color gamma-ray image sensor for the next-generation CT (I)

    Oshima Tsubasa, Kataoka Jun, Kishimoto Aya, Fujita Takuya, Kurei Youta, Nishiyama Toru, Yamamoto Seiichi, Ogawa Koichi

    Meeting Abstracts of the Physical Society of Japan   70   364 - 364  2015

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  • Development and evaluation of an ultra-fast ASIC for future PET scanners using TOF-capable MPPC array detectors

    T. Ambe, H. Ikeda, J. Kataoka, H. Matsuda, T. Kato

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   771   66 - 73  2015.01  [Refereed]

     View Summary

    We developed a front-end AMC for future PET scanners with Time-Of-Flight (TOF) capability to be coupled with 4 x 4 Multi-Pixel Photon Counter (MPPC) arrays. The ASIC is designed based on the open-IP project proposed by JAXA and realized in TSNIC 0.35 mu m CMOS technology. The circuit comprises 16-channel, low impedance current conveyors for effectively acquiring fast MPPC signals. For precise measurement of the coincidence timing of 511-keV gamma rays, the leading-edge method was used to discriminate the signals. We First tested the time response of the FOC by illuminating each channel of a MPPC array device 3 x 3 mm(2) in size with a Pico-second Light Pulsar with a light emission peak of 655 nm and pulse duration of 54 ps (FWHM). We obtained 105 ps (FWHM) on average for each channel in time jitter measurements. Moreover, we compensated for the time lag of each channel with inner delay circuits and succeeded in suppressing about a 700-ps lag to only 15 ps. This paper reports TOE measurements using back-to-back 511-key signals, and suggests that the ASIC can be a promising device for future TOF-PET scanners based on the MPPC array. (C) 2014 Published by Elsevier B.V.

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  • Development of high-precision color gamma-ray image sensor based on TSV-MPPC and diced scintillator arrays

    Tsubasa Oshima, Jun Kataoka, Aya Kishimoto, Takuya Fujita, Yota Kurei, Toru Nishiyama, Seiichi Yamamoto, Koichi Ogawa

    2015 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC)   803   8 - 14  2015  [Refereed]

     View Summary

    We developed a high-precision color gamma-ray image sensor with fine spatial resolution that is cost-effective, widely applicable, and very sensitive by using a diced cerium-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillator array coupled with a 3.0 x 3.0 mm(2)/pixel 8 x 8 MPPC-array. The proposed image sensor can measure the energy of individual X-ray photons transmitted through an object. The pixel size of the Ce: GAGG scintillator array is 0.2 mm, and the pixels are separated by 50-mu m-wide micro-grooves. The image sensor has a size of 20 x 20 mm(2) and thickness of 1.0 mm, and it achieved an excellent spatial resolution of 0.3-0.4 mm and energy resolutions of 12% and 18% (FWHM) for 122 and 59.5 keV gamma-rays, respectively. We conducted an experiment to determine the local effective atomic number of metals by using dual-energy gamma-ray sources. In addition, we developed a color-composite image using mixed images taken at three energies (31, 59.5, and 88 keV).

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    14
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  • Status and performance of the CALorimetric Electron Telescope (CALET) on the international space station

    O. Adriani, Y. Akaike, Y. Asaoka, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, M. Bongi, J. H. Buckley, A. Cassese, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. di Felice, H. Fuke, T. G. Guzik, T. Hamsa, N. Hasebe, M. Hareyama, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, Y. Katayose, J. Kataoka, R. Kataoka, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, H. M. Motz, A. A. Moiseev, K. Mori, M. Mori, N. Mori, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Nuclear Physics B - Proceedings Supplements   256-257   225 - 232  2014.12

     View Summary

    The CALorimetric Electron Telescope (CALET) space experiment, currently under development by Japan in collaboration with Italy and the United States, will measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma rays to 10 TeV and nuclei with Z=1 to 40 up to 1,000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma rays. The instrument will be launched to the ISS within 2014 Japanese Fiscal Year (by the end of March 2015) and installed on the Japanese Experiment Module-Exposed Facility (JEM-EF). In this paper, we will review the status and main science goals of the mission and describe the instrument configuration and performance.

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    10
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  • Development of prototype PET scanner using dual-sided readout DOI-PET modules

    T. Fujita, J. Kataoka, A. Kishimoto, Y. Kurei, T. Nishiyama, T. Ohshima, T. Taya

    JOURNAL OF INSTRUMENTATION   9 ( 12 ) P12015  2014.12  [Refereed]

     View Summary

    In our previous work, we proposed a novel design for a gamma-ray detector module capable of measuring the depth of interaction (DOI). In this paper, we further developed DOI-PET detector modules and a data acquisition system, and evaluated its performance. Each detector module was composed of a 3-D scintillator array and two large-area monolithic Multi-Pixel Photon Counter (MPPC) arrays coupled to both ends of the 3-D scintillator array, leading to only 8-ch signal outputs from a module. The 3-D scintillator array was composed of 9 x 9 x 7 matrices of 1.0 x 1.0 x 3.0 mm(3) Ce:GAGG crystals. The detector module showed good energy resolution of 10.6% as measured at 511 keV and a high average peak to valley ratio higher than 8 for each pixel crystal identified in the X-Y-Z directions. Moreover, we evaluated the spatial resolution of a virtual 18-ch PET gantry simulated by using two detector modules that were flexibly controlled using both the X-stage and theta-stage in 20-degree steps. By measuring a Na-22 point source (0.25 mm in diameter), we showed that spatial resolution substantially degrades from 1.0 mm to 7.8 mm (FWHM; as measured at 0 mm and 28 mm off-center) with a non-DOI configuration, whereas the corresponding values for the DOI configuration were 0.9 mm and 1.5 mm, respectively (FWHM; as measured at 0 mm and 28 mm off-center). This preliminary study confirms that our DOI-PET module is useful for future high spatial resolution and compact small-animal PET scanners without radial image distortions at the peripheral regions of the field of view (FOV).

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    5
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  • A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images

    T. Nishiyama, J. Kataoka, A. Kishimoto, T. Fujita, Y. Iwamoto, T. Taya, S. Ohsuka, S. Nakamura, M. Hirayanagi, N. Sakurai, S. Adachi, T. Uchiyama

    JOURNAL OF INSTRUMENTATION   9 ( 12 ) C12031  2014.12  [Refereed]

     View Summary

    After the Japanese nuclear disaster in 2011, large amounts of radioactive isotopes were released and still remain a serious problem in Japan. Consequently, various gamma cameras are being developed to help identify radiation hotspots and ensure effective decontamination operation. The Compton camera utilizes the kinematics of Compton scattering to contract images without using a mechanical collimator, and features a wide field of view. For instance, we have developed a novel Compton camera that features a small size (13x14x15 cm(3)) and light weight (1.9 kg), but which also achieves high sensitivity thanks to Ce:GAGG scintillators optically coupled wiith MPPC arrays. By definition, in such a Compton camera, gamma rays are expected to scatter in the "scatterer" and then be fully absorbed in the "absorber" (in what is called a forward-scattered event). However, high energy gamma rays often interact with the detector in the opposite direction-initially scattered in the absorber and then absorbed in the scatterer-in what is called a "back-scattered" event. Any contamination of such back-scattered events is known to substantially degrade the quality of gamma-ray images, but determining the order of gamma-ray interaction based solely on energy deposits in the scatterer and absorber is quite difficult. For this reason, we propose a novel yet simple Compton camera design that includes a rear-panel shield (a few mm thick) consisting of W or Pb located just behind the scatterer. Since the energy of scattered gamma rays in back-scattered events is much lower than that in forward-scattered events, we can effectively discriminate and reduce back-scattered events to improve the signal-to-noise ratio in the images. This paper presents our detailed optimization of the rear-panel shield using Geant4 simulation, and describes a demonstration test using our Compton camera.

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    3
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  • Development of a MPPC-based prototype gantry for future MRI-PET scanners

    Y. Kurei, J. Kataoka, T. Kato, T. Fujita, T. Ohshima, T. Taya, S. Yamamoto

    JOURNAL OF INSTRUMENTATION   9 ( 12 ) C12052  2014.12  [Refereed]

     View Summary

    We have developed a high spatial resolution, compact Positron Emission Tomography (PET) module designed for small animals and intended for use in magnetic resonance imaging (MRI) systems. This module consists of large-area, 4x4 ch MPPC arrays (S11830-3344MF; Hamamatsu Photonics K. K.) optically coupled with Ce-doped (Lu, Y)(2)(SiO4)O (Ce: LYSO) scintillators fabricated into 16 x 16 matrices of 0.5 x 0.5 mm(2) pixels. We set the temperature sensor (LM73CIMK-0; National Semiconductor Corp.) at the rear of the MPPC acceptance surface, and apply optimum voltage to maintain the gain. The eight MPPC-based PET modules and coincidence circuits were assembled into a gantry arranged in a ring 90 mmin diameter to form the MPPC-based PET system. We have developed two types PET gantry: one made of non-magnetic metal and the other made of acrylonitrile butadiene styrene (ABS) resins. The PET gantry was positioned around the RF coil of the 4.7 T MRI system. We took an image of a point Na-22 source under fast spin echo (FSE) and gradient echo (GE), in order to measure the interference between the MPPC-based PET and MRI. The spatial resolution of PET imaging in a transaxial plane of about 1 mm (FWHM) was achieved in all cases. Operating with PET made of ABS has no effect on MR images, while operating with PET made of non-magnetic metal has a significant detrimental effect on MR images. This paper describes our quantitative evaluations of PET images and MR images, and presents a more advanced version of the gantry for future MRI/DOI-PET systems.

    DOI

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    1
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  • Performance and field tests of a handheld Compton camera using 3-D position-sensitive scintillators coupled to multi-pixel photon counter arrays

    A. Kishimoto, J. Kataoka, T. Nishiyama, T. Fujita, K. Takeuchi, H. Okochi, H. Ogata, H. Kuroshima, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, H. Suzuki

    JOURNAL OF INSTRUMENTATION   9 ( 11 )  2014.11  [Refereed]

     View Summary

    After the nuclear disaster in Fukushima, radiation decontamination has become particularly urgent. To help identify radiation hotspots and ensure effective decontamination operation, we have developed a novel Compton camera based on Ce-doped Gd3Al2Ga3O12 scintillators and multi-pixel photon counter (MPPC) arrays. Even though its sensitivity is several times better than that of other cameras being tested in Fukushima, we introduce a depth-of-interaction (DOI) method to further improve the angular resolution. For gamma rays, the DOI information, in addition to 2-D position, is obtained by measuring the pulse-height ratio of the MPPC arrays coupled to ends of the scintillator. We present the detailed performance and results of various field tests conducted in Fukushima with the prototype 2-D and DOI Compton cameras. Moreover, we demonstrate stereo measurement of gamma rays that enables measurement of not only direction but also approximate distance to radioactive hotspots.

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    51
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  • Qualification test of a MPPC-based PET module for future MRI-PET scanners

    Y. Kurei, J. Kataoka, T. Kato, T. Fujita, H. Funamoto, T. Tsujikawa, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   765   275 - 279  2014.11  [Refereed]

     View Summary

    We have developed a high-resolution, compact Positron Emission Tomography (PET) module for future use in MRI-PET scanners. The module consists of large-area, 4 x 4 ch MPPC arrays (Hamamatsu S11827-3344MG) optically coupled with Ce:LYSO scintillators fabricated into 12 x 12 matrices of 1 x 1 mm(2) pixels. At this stage, a pair of module and coincidence circuits was assembled into an experimental prototype gantry arranged in a ring of 90 mm in diameter to form the MPPC-based PET system. The PET detector ring was then positioned around the RF coil of the 4.7 T MRI system. We took an image of a point Na-22 source under fast spin echo (FSE) and gradient echo (GE), in order to measure interference between the MPPC-based PET and the MRI We only found a slight degradation in the spatial resolution of the PET image from 1.63 to 1.70 mm (FWHM; x-direction), or 1.48-1.55 mm (FWHM; y-direction) when operating with the MRI, while the signal-to-noise ratio (SNR) of the MRI image was only degraded by 5%. These results encouraged us to develop a more advanced version of the MRI-PET gantry with eight MPPC-based PET modules, whose detailed design and first qualification Lest are also presented in this paper. (C) 2014 Elsevier B.V. All rights reserved.

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    2
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  • Two-dimensional diced scintillator array for innovative, fine-resolution gamma camera

    T. Fujita, J. Kataoka, T. Nishiyama, S. Ohsuka, S. Nakamura, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   765   262 - 268  2014.11  [Refereed]

     View Summary

    We are developing a technique to fabricate fine spatial resolution (FWHM &lt; 0.5 mm) and cost-effective photon counting detectors, by using silicon photomultipliers (SiPMs) coupled with a finely pixelated scintillator plate. Unlike traditional X-ray imagers that use a micro-columnar CskTI) plate, we can pixelate various scintillation crystal plates more than 1 mm thick, and easily develop large-area, finepitch scintillator arrays with high precision. Coupling a fine pitch scintillator array with a SiPM array results in a compact, fast-response detector that is ideal for X-ray, gamma-ray, and charged particle detection as used in autoradiography, gamma cameras, and photon counting CTs. As the first step, we fabricated a 2-D, cerium-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillator array of 0.25 mm pitch, by using a dicing saw to cut micro-grooves 50 um wide into a 1.0 mm thick Ce:GAGG plate. The scinfillator plate is optically coupled with a 3.0 x 3.0 mm pixel 4 x 4 SiPM array and read-out via the resistive chargedivision network. Even when using this simple system as a gamma camera, we obtained excellent spatial resolution of 0.48 mm (F\NHM) for 122 keV gamma-rays. We will present our plans to further improve the signal-to-noise ratio in the image, and also discuss a variety of possible applications in the near future. (C) 2014 Elsevier By, All rights reserved,

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  • "Stereo Compton cameras" for the 3-D localization of radioisotopes

    K. Takeuchi, J. Kataoka, T. Nishiyama, T. Fujita, A. Kishimoto, S. Ohsuka, S. Nakamura, S. Adachi, M. Hirayanagi, T. Uchiyama, Y. Ishikawa, T. Kato

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   765 ( 21 ) 187 - 191  2014.11  [Refereed]

     View Summary

    The Compton camera is a viable and convenient tool used to visualize the distribution of radioactive isotopes that emit gamma rays. After the nuclear disaster in Fukushima in 2011, there is a particularly urgent need to develop "gamma cameras", which can visualize the distribution of such radioisotopes. In response, we propose a portable Compton camera, which comprises 3-0 position-sensitive GAGG scintillators coupled with thin monolithic MPPC arrays. The pulse-height ratio of two MPPC-arrays allocated at both ends of the scintillator block determines the depth of interaction (DOI), which dramatically improves the position resolution of the scintillation detectors. We report on the detailed optimization of the detector design, based on Geant4 simulation. The results indicate that detection efficiency reaches up to 0.54%, or more than 10 times that of other cameras being tested in Fukushima, along with a moderate angular resolution of 8.1 (FWHM). By applying the triangular surveying method, we also propose a new concept for the stereo measurement of gamma rays by using two Compton cameras, thus enabling the 3-D positional measurement of radioactive isotopes for the first time. From one point source simulation data, we ensured that the source position and the distance to the same could be determined typically to within 2 meters' accuracy and we also confirmed that more than two sources are clearly separated by the event selection from two point sources of simulation data. (C) 2014 Elsevier B.V. All rights reserved.

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    23
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  • Performance of the latest MPPCs with reduced dark counts and improved photon detection efficiency

    T. Tsujikawa, H. Funamoto, J. Kataoka, T. Fujita, T. Nishiyama, Y. Kurei, K. Sato, K. Yamamura, S. Nakamura

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   765 ( 21 ) 247 - 251  2014.11  [Refereed]

     View Summary

    We have tested the performance of two types of the latest Multi-Pixel Photon Counters (MPPCs; measuring 3 x 3 mm2 in size) developed by Hamamatsu Photonics K.K. The new S12572-050C is a successor to the S10362-33-050C (i.e., conventional 3 x 3-mm2 pixel MPPC of 50 pm pitch), comprises 3600 Geiger mode avalanche photodiodes (APDs), and also features high gain (up to 125 x 10(6)), a low dark count (up to 10(6) cps), and improved photon detection efficiency (PDE) by up to 30%. The S12572015C is a new type of fine-pitch (15 pM) MPPC featuring a wide dynamic range and fast timing response. This paper first presents the detailed performance of these latest MPPCs as photon counting devices. It then describes our fabrication of a prototype detector consisting of a MPPC optically coupled with a Ce: GAGG scintillator. We obtained average FVVHM energy resolutions o17,3% (15 mu M) and 6.7% (new-50 [iri), as compared Lo 6.9% (old-50 mu M) for 662-key gamma rays from the Cs-137 source, as measured at 20 degrees C. Moreover, the number of fired pixels for 662-keV gamma rays increased by 30% for the new-50 mu m (as compared to the old-50 mu m). We confirmed that the low energy threshold improved from 10 kV to 4 keY, when using the latest MPPC device (new-50 pm). We also confirmed that the timing resolution of the new MPPC is 50 ps or even better, as compared to 89 ps of the old MPPC. The results thus confirm that these new types of IVIPPCs are promising for various applications as scintillation detectors. (C) 2014 Elsevier B.V. All rights reserved.

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    5
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  • The spectrum and morphology of the Fermi bubbles

    M. Ackermann, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, L. Di Venere, E. Do Couto E Silva, P. S. Drell, C. Favuzzi, E. C. Ferrara, W. B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, S. Guiriec, D. Hadasch, A. K. Harding, E. Hays, J. W. Hewitt, X. Hou, T. Jogler, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, J. Kataoka, J. Knödlseder, D. Kocevski, M. Kuss, S. Larsson, L. Latronico, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, D. Malyshev, A. Manfreda, F. Massaro, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, R. Nemmen, E. Nuss, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta

    Astrophysical Journal   793 ( 1 )  2014.09

     View Summary

    The Fermi bubbles are two large structures in the gamma-ray sky extending to 55° above and below the Galactic center. We analyze 50 months of Fermi Large Area Telescope data between 100 MeV and 500 GeV above 10° in Galactic latitude to derive the spectrum and morphology of the Fermi bubbles. We thoroughly explore the systematic uncertainties that arise when modeling the Galactic diffuse emission through two separate approaches. The gamma-ray spectrum is well described by either a log parabola or a power law with an exponential cutoff. We exclude a simple power law with more than 7σ significance. The power law with an exponential cutoff has an index of 1.9 ± 0.2 and a cutoff energy of 110 ± 50 GeV. We find that the gamma-ray luminosity of the bubbles is erg s-1. We confirm a significant enhancement of gamma-ray emission in the southeastern part of the bubbles, but we do not find significant evidence for a jet. No significant variation of the spectrum across the bubbles is detected. The width of the boundary of the bubbles is estimated to be deg. Both inverse Compton (IC) models and hadronic models including IC emission from secondary leptons fit the gamma-ray data well. In the IC scenario, synchrotron emission from the same population of electrons can also explain the WMAP and Planck microwave haze with a magnetic field between 5 and 20 μG.

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  • Pre-flight performance of a micro-satellite TSUBAME for X-ray polarimetry of gamma-ray bursts

    Yatsu Yoichi, Ito Kei, Kurita Shin, Arimoto Makoto, Kawai Nobuyuki, Matsushita Masanori, Kawajiri Shota, Kitamura Shogo, Matunaga Saburo, Kimura Shin'ichi, Kataoka Jun, Nakamori Takeshi, Kubo Sin

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144  2014.07

     View Summary

    To measure the polarization of gamma-ray bursts in X-ray energy band, we have developed a 50 kg micro-satellite named "SUBAME". The satellite has a compact and high-sensitive hard X-ray polarimeter employing newly-developed shock resistant multi-anode photomultipliers and Si avalanche photodiodes. Thanks to the ultra low-noise detectors and signal processors, the polarimeter can cover a wide energy range of 30 200 keV even at 25°C with a high modulation factor of 62 %. TSUBAME is in the phase of final functional tests waiting for shipping to Baikonur and will be launched into a sun-synchronous orbit at an altitude of 700 km in late 2014. In this paper, the pre-ight performance of the gamma-ray detector system and the satellite bus system are presented.

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    7
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  • EXTREME BLAZARS STUDIED WITH FERMI-LAT AND SUZAKU: 1ES 0347-121 AND BLAZAR CANDIDATE HESS J1943+213

    Tanaka, Y. T, Stawarz, L, Finke, J, Cheung, C. C, Dermer, C. D, Kataoka, J, Bamba, A, Dubus, G, De Naurois, M, Wagner, S. J

    ASTROPHYSICAL JOURNAL   787 ( 2 )  2014.06  [Refereed]

     View Summary

    We report on our study of high-energy properties of two peculiar TeV emitters: the extreme blazar&quot; 1ES 0347-121 and the &quot;extreme blazar candidate&quot; HESS J1943+213 located near the Galactic plane. Both objects are characterized by quiescent synchrotron emission with flat spectra extending up to the hard X-ray range, and both were reported to be missing GeV counterparts in the Fermi Large Area Telescope (LAT) two-year Source Catalog. We analyze a 4.5 yr accumulation of the Fermi-LAT data, resulting in the detection of 1ES 0347-121 in the GeV band, as well as in improved upper limits for HESS J1943+213. We also present the analysis results of newly acquired Suzaku data for HESS J1943+213. The X-ray spectrum is well represented by a single power law extending up to 25 keV with photon index 2.00 +/- 0.02 and a moderate absorption in excess of the Galactic value, which is in agreement with previous X-ray observations. No short-term X-ray variability was found over the 80 ks duration of the Suzaku exposure. Under the blazar hypothesis, we modeled the spectral energy distributions of 1ES 0347-121 and HESS J1943+213, and we derived constraints on the intergalactic magnetic fie

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    26
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  • Search for cosmic-ray-induced gamma-ray emission in galaxy clusters

    M. Ackermann, M. Ajello, A. Albert, A. Allafort, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. D. Bloom, E. Bonamente, E. Bottacini, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, E. Cavazzuti, R. C.G. Chaves, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, A. Franckowiak, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, J. Hewitt, R. E. Hughes, T. E. Jeltema, G. Jóhannesson, A. S. Johnson, T. Kamae, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, R. Nemmen, E. Nuss, T. Ohsugi, M. Orienti, E. Orlando, J. F. Ormes, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, J. Ruan, M. Sánchez-Conde

    Astrophysical Journal   787 ( 1 )  2014.05

     View Summary

    Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into γ rays that are potentially observable with the Large Area Telescope (LAT) on board the Fermi space telescope. We present a joint likelihood analysis searching for spatially extended γ-ray emission at the locations of 50 galaxy clusters in four years of Fermi-LAT data under the assumption of the universal cosmic-ray (CR) model proposed by Pinzke & Pfrommer. We find an excess at a significance of 2.7σ, which upon closer inspection, however, is correlated to individual excess emission toward three galaxy clusters: A400, A1367, and A3112. We discuss these cases in detail and conservatively attribute the emission to unmodeled background systems (for example, radio galaxies within the clusters).Through the combined analysis of 50 clusters, we exclude hadronic injection efficiencies in simple hadronic models above 21% and establish limits on the CR to thermal pressure ratio within the virial radius, R 200, to be below 1.25%-1.4% depending on the morphological classification. In addition, we derive new limits on the γ-ray flux from individual clusters in our sample. © 2014. The American Astronomical Society. All rights reserved.

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  • Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy γ-rays

    J. Aleksić, S. Ansoldi, L. A. Antonelli, P. Antoranz, A. Babic, P. Bangale, U. Barres De Almeida, J. A. Barrio, J. Becerra González, W. Bednarek, K. Berger, E. Bernardini, A. Biland, O. Blanch, R. K. Bock, S. Bonnefoy, G. Bonnoli, F. Borracci, T. Bretz, E. Carmona, A. Carosi, D. Carreto Fidalgo, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, P. Da Vela, F. Dazzi, A. De Angelis, G. De Caneva, B. De Lotto, C. Delgado Mendez, M. Doert, A. Domínguez, D. Dominis Prester, D. Dorner, M. Doro, S. Einecke, D. Eisenacher, D. Elsaesser, E. Farina, D. Ferenc, M. V. Fonseca, L. Font, K. Frantzen, C. Fruck, R. J. García López, M. Garczarczyk, D. Garrido Terrats, M. Gaug, G. Giavitto, N. Godinović, A. González Muñoz, S. R. Gozzini, A. Hadamek, D. Hadasch, A. Herrero, D. Hildebrand, J. Hose, D. Hrupec, W. Idec, V. Kadenius, H. Kellermann, M. L. Knoetig, J. Krause, J. Kushida, A. La Barbera, D. Lelas, N. Lewandowska, E. Lindfors, S. Lombardi, M. López, R. López-Coto, A. López-Oramas, E. Lorenz, I. Lozano, M. Makariev, K. Mallot, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, B. Marcote, M. Mariotti, M. Martínez, D. Mazin, U. Menzel, M. Meucci, J. M. Miranda, R. Mirzoyan, A. Moralejo, P. Munar-Adrover, D. Nakajima, A. Niedzwiecki, K. Nilsson, N. Nowak, R. Orito, A. Overkemping, S. Paiano

    Astronomy and Astrophysics   564  2014.04

     View Summary

    Aims. The radio galaxy NGC≠1275, recently identified as a very high energy (VHE, >100 GeV) γ-ray emitter by MAGIC, is one of the few non-blazar active galactic nuclei detected in the VHE regime. The purpose of this work is to better understand the origin of the γ-ray emission and locate it within the galaxy. Methods. We studied contemporaneous multifrequency observations of NGC≠1275 and modeled the overall spectral energy distribution. We analyzed unpublished MAGIC observations carried out between October 2009 and February 2010, and the previously published observations taken between August 2010 and February 2011. We studied the multiband variability and correlations by analyzing data of Fermi-LAT in the 100 MeV-100 GeV energy band, as well as Chandra (X-ray), KVA (optical), and MOJAVE (radio) data taken during the same period. Results. Using customized Monte Carlo simulations corresponding to early MAGIC stereoscopic data, we detect NGC≠1275 also in the earlier MAGIC campaign. The flux level and energy spectra are similar to the results of the second campaign. The monthly light curve above 100 GeV shows a hint of variability at the 3.6σ level. In the Fermi-LAT band, both flux and spectral shape variabilities are reported. The optical light curve is also variable and shows a clear correlation with the γ-ray flux above 100 MeV. In radio, three compact components are resolved in the innermost part of the jet. One of these components shows a similar trend as the Fermi-LAT and KVA light curves. The γ-ray spectra measured simultaneously with MAGIC and Fermi-LAT from 100 MeV to 650 GeV can be well fitted either by a log-parabola or by a power-law with a subexponential cutoff for the two observation campaigns. A single-zone synchrotron-self-Compton model, with an electron spectrum following a power-law with an exponential cutoff, can explain the broadband spectral energy distribution and the multifrequency behavior of the source. However, this model suggests an untypical low bulk-Lorentz factor or a velocity alignment closer to the line of sight than the parsec-scale radio jet. © 2014 ESO.

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  • Development of a Prototype Detector Using APD-Arrays Coupled With Pixelized Ce:GAGG Scintillator for High Resolution Radiation Imaging

    Kei Kamada, Kenji Shimazoe, Shigeki Ito, Masao Yoshino, Takanori Endo, Kousuke Tsutsumi, Jun Kataoka, Shunsuke Kurosawa, Yuui Yokota, Hiroyuki Takahashi, Akira Yoshikawa

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   61 ( 1 ) 348 - 352  2014.02  [Refereed]

     View Summary

    A novel digital PET scanner based on Time over Threshold method is developed. The positron emission tomography (PET) is composed of 144channel Ce:Gd3Al2Ga3O12 (GAGG)-Avaranche photodiode (APD) detector arrays individually coupled with custom designed Time over Threshold (ToT) application-specific integrated circuit (ASIC) to realize the high count rate and good spatial resolution. Such an imaging system provides a simple front-end circuit and flexible digital signal processing like multiplexing such as a pulse train method. The measured energy resolution of the detector system was 6.7% for the 511 keV peak, and 4.25 ns time resolution was measured with a single detector module. The measured spatial resolution for a point source was 1.37 mm FWHM for our initial data with a columnar Na-22 source.

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    18
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  • Observational aspects of AGN jets at high energy

    Jun Kataoka

    Proceedings of the International Astronomical Union   10 ( S313 ) 1 - 11  2014

     View Summary

    For the last two decades, significant and dramatic progress has been made in understanding astrophysical jet sources, particularly in the X-ray and gamma-ray energy bands. For example, the Chandra X-ray observatory reveals a number of AGN jets extending from kpc to Mpc scales. More recently, the Fermi Gamma-ray Space Telescopes launched in 2008 started monitoring the gamma-ray sky with excellent sensitivity of about ten times greater than that of EGRET onboard CGRO, and has detected more than 2, 000 sources (mostly AGNs) as of 2014. Moreover, Fermi-LAT has discovered gamma-ray emissions not only from blazars but from a dozen radio galaxies not previously known to emit gamma-rays. Closer to home, the Fermi-bubbles were discovered to extend 50 degrees above and below the Galactic center. These large scale diffuse gamma-ray structures are similar in structure to AGN lobes such as those seen in Cen A and provide evidence for past activity in our Galactic center. In this review, I will first summarize recent highlights of large scale jets in radio galaxies, specifically resolved by the Chandra X-ray observatory. Next I will move on to the gamma-ray sky to present some highlights from Fermi-LAT observations of "misaligned" blazars, namely radio galaxies. I will discuss a unification scheme connecting blazars and misaligned radio galaxies. In the last part, I will also briefly comment on recent multiband observations of the Fermi-bubble and possible impacts on the AGN jet physics in the near future.

    DOI

  • ASTRO-H White Paper - Plasma Diagnostic and Dynamics of the Galactic Center Region

    K. Koyama, J. Kataoka, M. Nobukawa, H. Uchiyama, S. Nakashima, F. Aharonian, M. Chernyakova, Y. Ichinohe, K. K. Nobukawa, Y. Maeda, H. Matsumoto, H. Murakami, C. Ricci, L. Stawarz, T. Tanaka, T. G. Tsuru, S. Watanabe, S. Yamauchi, T. Yuasa, for the ASTRO-H, Science Working Group

    arXiv    2014

  • Development and verification of signal processing system of BGO active shield onboard Astro-H

    Masanori Ohno, Shin'ya Tokuda, Takafumi Kawano, Shunya Furui, Ikumi Edahiro, Hiromitsu Takahashi, Kunihiro Goto, Yasushi Fukazawa, Hiroaki Murakami, Syogo Kobayashi, Soki Sakurai, Makoto Sasano, Shunsuke Torii, Toshio Nakano, Ko Ono, Kazuma Miyake, Terukazu Nishida, Kazuhiro Nakazawa, Kazuo Makishima, Kouichi Hagino, Takayuki Yuasa, Hirokazu Odaka, Rie Sato, Shin Watanabe, Motohide Kokubun, Tadayuki Takahashi, Goro Sato, Jun Kataoka, Tatsuhiko Saito, Kazutaka Yamaoka, Hiroyasu Tajima, Yoichi Yatsu, Takeshi Nakamori, Hideki Uchiyama, Daisuke Yonetoku

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144  2014  [Refereed]

     View Summary

    The hard X-ray imager (HXI) and soft gamma-ray detector (SGD) onboard Astro-H observe astronomical objects with high sensitivity in the hard X-ray (5-80 keV) and soft gamma-ray (40-600 keV) energy bands. To achieve this high sensitivity, background rejection is essential, and these detectors are surrounded by large and thick bismuth germinate scintillators as an active shield. We have developed adequate trigger logic for both the HXI and SGD to process signals from main detector and BGO shield simultaneously and then we optimized the trigger delay and width, with consideration of the trigger latch efficiency. The shield detector system performs well, even after it is assembled as the HXI sensor. The energy threshold maintains the same level as that observed during the prototype development phase, and the experimental room background level of the main detector is successfully reduced by our optimized trigger timing.

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  • Development of the camera for the Large Size Telescopes of the Cherenkov Telescope Array

    Y. Inome, G. Ambrosi, Y. Awane, H. Baba, A. Bamba, M. Barcelo, U. Barres de Almeida, J. A. Barrio, O. Blanch Bigas, J. Boix, L. Brunetti, E. Carmona, E. Chabanne, M. Chikawa, N. Cho, P. Colin, J. L. Conteras, J. Cortina, F. Dazzi, A. Deangelis, G. Deleglise, C. Delgado, C. Diaz, F. Dubois, A. Fiasson, D. Fink, N. Fouque, L. Freixas, C. Fruck, A. Gadola, R. Garcia, D. Gascon, N. Geffroy, N. Giglietto, F. Giordano, F. Granena, S. Gunji, R. Hagiwara, N. Hamer, Y. Hanabata, T. Hassan, K. Hatanaka, T. Haubold, M. Hayashida, R. Hermel, D. Herranz, K. Hirotani, J. Hose, D. Hugh, S. Inoue, Y. Inoue, K. Ioka, C. Jablonski, M. Kagaya, H. Katagiri, J. Kataoka, H. Kellermann, T. Kishimoto, M. Knoetig, K. Kodani, K. Kohri, T. Kojima, Y. Konno, S. Koyama, H. Kubo, J. Kushida, G. Lamanna, T. Le Flour, M. Lopez-Moya, R. Lopez, E. Lorenz, P. Majumdar, A. Manalaysay, M. Mariotti, G. Martinez, M. Martinez, S. Masuda, S. Matsuoka, D. Mazin, U. Menzel, J. M. Miranda, R. Mirzoyan, I. Monteiro, A. Moralejo, K. Murase, S. Nagataki, T. Nagayoshi, D. Nakajima, T. Nakamori, K. Nishijima, K. Noda, A. Nozato, M. Ogino, Y. Ohira, M. Ohishi, H. Ohoka, A. Okumura, S. Ono, R. Orito, J. L. Panazol, D. Paneque, R. Paoletti, J. M. Paredes, G. Pauletta, S. Podkladkin, J. Prast, R. Rando, O. Reimann, M. Ribo, S. Rosier-Lees, K. Saito, T. Saito, Y. Saito, N. Sakaki, R. Sakonaka, A. Sanuy, M. Sawada, V. Scalzotto, S. Schultz, T. Schweizer, T. Shibata, S. Shu, J. Sieiro, V. Stamatescu, S. Steiner, U. Straumann, R. Sugawara, H. Tajima, H. Takami, M. Takahashi, S. Tanaka, M. Tanaka, L. A. Tejedor, Y. Terada, M. Teshima, Y. Tomono, T. Totani, T. Toyama, Y. Tsubone, Y. Tsuchiya, S. Tsujimoto, H. Ueno, K. Umehara, Y. Umetsu, A. Vollhardt, R. Wagner, H. Wetteskind, T. Yamamoto, R. Yamazaki, A. Yoshida, T. Yoshida, T. Yoshikoshi

    ADVANCES IN OPTICAL AND MECHANICAL TECHNOLOGIES FOR TELESCOPES AND INSTRUMENTATION   9151   914542 - 8pp  2014

     View Summary

    The Large Size Telescopes, LSTs, located at the center of the Cherenkov Telescope Array, CTA, will be sensitive for low energy gamma-rays. The camera on the LST focal plane is optimized to detect low energy events based on a high photon detection efficiency and high speed electronics. Also the trigger system is designed to detect low energy showers as much as possible. In addition, the camera is required to work stably without maintenance in a few tens of years. In this contribution we present the design of the camera for the first LST and the status of its development and production.

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  • Soft Gamma-ray Detector (SGD) onboard the ASTRO-H

    Fukazawa Yasushi, Tajima Hiroyasu, Watanabe Shin, Blandford Roger, Hayashi Katsuhiro, Harayama Atsushi, Kataoka Jun, Kawaharada Madoka, Kokubun Motohide, Laurent Philippe, Lebrun Francois, Limousin Olivier, Madejski Grzegorz M, Makishima Kazuo, Mizuno Tsunefumi, Mori Kunishiro, Nakamori Takeshi, Nakazawa Kazuhiro, Noda Hirofumi, Odaka Hirokazu, Ohno Masanori, Ohta Masayuki, Saito Shin'ya, Sato Goro, Sato Rie, Takeda Shin'ichiro, Takahashi Hiromitsu, Takahashi Tadayuki, Tanaka Yasuyuki, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Yamaoka Kazutaka, Yatsu Yoichi, Yonetoku Daisuke, Yuasa Takayuki

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144  2014  [Refereed]

     View Summary

    The Soft Gamma-ray Detector (SGD) is one of observational instruments onboard the ASTRO-H, and will provide 10 times better sensitivity in 60{600 keV than the past and current observatories. The SGD utilizes similar technologies to the Hard X-ray Imager (HXI) onboard the ASTRO-H. The SGD achieves low background by constraining gamma-ray events within a narrow field-of-view by Compton kinematics, in addition to the BGO active shield. In this paper, we will present the results of various tests using engineering models and also report the flight model production and evaluations.

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  • The hard X-ray imager (HXI) for the ASTRO-H mission

    Sato G, Kokubun M, Nakazawa K, Enoto T, Fukazawa Y, Harayama A, Hayashi K, Kataoka J, Katsuta J, Kawaharada M, Laurent P, Lebrun F, Limousin O, Makishima K, Mizuno T, Mori K, Nakamori T, Noda H, Odaka H, Ohno M, Ohta M, Saito S, Sato R, Tajima H, Takahashi H, Takahashi T, Takeda S, Terada Y, Uchiyama H, Uchiyama Y, Watanabe S, Yamaoka K, Yatsu Y, Yuasa T

    Proceedings of SPIE - The International Society for Optical Engineering   9144  2014  [Refereed]

     View Summary

    The 6th Japanese X-ray satellite, ASTRO-H, is scheduled for launch in 2015. The hard X-ray focusing imaging system will observe astronomical objects with the sensitivity for detecting point sources with a brightness of 1/100,000 times fainter than the Crab nebula at > 10 keV. The Hard X-ray Imager (HXI) is a focal plane detector 12 m below the hard X-ray telescope (HXT) covering the energy range from 5 to 80 keV. The HXI is composed of a stacked Si/CdTe semiconductor detector module and surrounding BGO scintillators. The latter work as active shields for efficient reduction of background events caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we describe the detector system, and present current status of flight model development, and performance of HXI using an engineering model of HXI.

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    23
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  • 大面積MPPC array を用いた放射線検出器の最前線

    片岡 淳

    放射線(応用物理学会・放射線分科会)   39 ( 3 ) 117 - 126  2014

    CiNii

  • Evaluation of the performance limit of MPPC for ToF-PET

    Takayuki Tsujikawa, Jun Kataoka, Takahiro Ambe, Takuya Fujita, Yota Kurei, Goro Sato, Hirolazu Ikeda

    2014 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC)    2014  [Refereed]

     View Summary

    In recent years, multi-pixel photon counters (MP-PCs) have been actively studied for use in a module for such next-generation PET systems as MRI-PET, DoI-PET, and ToF-PET scanners. In particular, Time of Flight (ToF) measurement is a challenging approach to identify the position of a gamma-ray source, according to differences in the arrival times of annihilation gamma rays after positron decay. Several simulations suggest a substantial improvement in the signal-to-noise ratio of PET images when using ToF information. However, ToF-PET performance is determined by the time resolution of a gamma-ray sensor (including scintillators, photo-sensors and readout electronics) as a whole, thus making it often difficult to achieve ToF resolution as good as 500 ps (FWHM) in actual PET systems. This paper describes our development of a new method of ToF measurement using MPPC-based scintillation detectors. We showed that our method effectively reduces the contamination of dark noise, and minimizes the effects of time walk and timing jitter. The best ToF resolution of 213 ps (FWHM) was achieved by coupling 3x3x10 mm(3) Ce:LYSO crystal with a 3x3 mm(2) pixel detector. We conclude by commenting on our ultra-fast ASIC for 16-ch MPPC readout as pertaining to future applications in MPPC-PET scanners with ToF measurement capability.

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  • The first FERMI-LAT catalog of sources above 10 GeV

    M. Ackermann, M. Ajello, A. Allafort, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, A. Belfiore, R. Bellazzini, E. Bernieri, E. Bissaldi, E. D. Bloom, E. Bonamente, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, R. Campana, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, R. C.G. Chaves, A. Chekhtman, C. C. Cheung, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, A. Franckowiak, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, J. Hewitt, A. B. Hill, D. Horan, R. E. Hughes, T. Jogler, G. Jóhannesson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, J. Kataoka, T. Kawano, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, E. Massaro, M. Mayer

    Astrophysical Journal, Supplement Series   209 ( 2 )  2013.12

     View Summary

    We present a catalog of γ-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first 3 yr of the Fermi Gamma-ray Space Telescope mission. The first Fermi-LAT catalog of >10 GeV sources (1FHL) has 514 sources. For each source we present location, spectrum, a measure of variability, and associations with cataloged sources at other wavelengths. We found that 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei. Of the 27 sources associated with known pulsars, we find 20 (12) to have significant pulsations in the range >10 GeV (>25 GeV). In this work we also report that, at energies above 10 GeV, unresolved sources account for 27% ± 8% of the isotropic γ-ray background, while the unresolved Galactic population contributes only at the few percent level to the Galactic diffuse background. We also highlight the subset of the 1FHL sources that are best candidates for detection at energies above 50-100 GeV with current and future ground-based γ-ray observatories. © 2013. The American Astronomical Society. All rights reserved..

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  • Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    J. Kataoka, A. Kishimoto, T. Nishiyama, T. Fujita, K. Takeuchi, T. Kato, T. Nakamori, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, K. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   732   403 - 407  2013.12

     View Summary

    The release of radioactive isotopes (mainly Cs-137, Cs-134 and till) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just similar to 10 cm(2) in size. Despite its compactness, the camera realizes a wide 180 degrees field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 mu Sv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10 degrees (FWHM). The 3D position sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5 x 14 x 16 cm(3) in size) being fabricated by Hamamatsu Photonics K. K. Although the camera still operates in non-DOI mode, angular resolution as high as 14 degrees (FWHM) was achieved with an integration time of 30s for the assumed hotspot described above. (C) 2013 Elsevier B.V. All tights reserved.

    DOI

    Scopus

    127
    Citation
    (Scopus)
  • SUZAKU OBSERVATIONS OF THE DIFFUSE X-RAY EMISSION ACROSS THE FERMI BUBBLES' EDGES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, L. Stawarz, Y. Takahashi, Y. Takeuchi, H. Tsunemi, M. Kimura, Y. Takei, C. C. Cheung, Y. Inoue, T. Nakamori

    ASTROPHYSICAL JOURNAL   779 ( 1 )  2013.12

     View Summary

    We present Suzaku X-ray observations along two edge regions of the Fermi Bubbles, with eight similar or equal to 20 ks pointings across the northern part of the North Polar Spur (NPS) surrounding the north bubble and six across the southernmost edge of the south bubble. After removing compact X-ray features, diffuse X-ray emission is clearly detected and is well reproduced by a three-component spectral model consisting of unabsorbed thermal emission (temperature kT similar or equal to 0.1 keV) from the Local Bubble, absorbed kT similar or equal to 0.3 keV thermal emission related to the NPS and/or Galactic halo (GH), and a power-law component at a level consistent with the cosmic X-ray background. The emission measure (EM) of the 0.3 keV plasma decreases by similar or equal to 50% toward the inner regions of the northeast bubble, with no accompanying temperature change. However, such a jump in the EM is not clearly seen in the south bubble data. While it is unclear whether the NPS originates from a nearby supernova remnant or is related to previous activity within or around the Galactic center, our Suzaku observations provide evidence that suggests the latter scenario. In the latter framework, the presence of a large amount of neutral matter absorbing the X-ray emission as well as the existence of the kT similar or equal to 0.3 keV gas can be naturally interpreted as a weak shock driven by the bubbles' expansion in the surrounding medium, with velocity v(exp) similar or equal to 300 km s(-1) (corresponding to shock Mach number M similar or equal to 1.5), compressing the GH gas to form the NPS feature. We also derived an upper limit for any non-thermal X-ray emission component associated with the bubbles and demonstrate that, in agreement with the aforementioned findings, the non-thermal pressure and energy estimated from a one-zone leptonic model of its broadband spectrum, are in rough equilibrium with that of the surrounding thermal plasma.

    DOI

    Scopus

    100
    Citation
    (Scopus)
  • Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    J. Kataoka, A. Kishimoto, T. Nishiyama, T. Fujita, K. Takeuchi, T. Kato, T. Nakamori, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, K. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   732   403 - 407  2013.12  [Refereed]

     View Summary

    The release of radioactive isotopes (mainly Cs-137, Cs-134 and till) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just similar to 10 cm(2) in size. Despite its compactness, the camera realizes a wide 180 degrees field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 mu Sv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10 degrees (FWHM). The 3D position sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5 x 14 x 16 cm(3) in size) being fabricated by Hamamatsu Photonics K. K. Although the camera still operates in non-DOI mode, angular resolution as high as 14 degrees (FWHM) was achieved with an integration time of 30s for the assumed hotspot described above. (C) 2013 Elsevier B.V. All tights reserved.

    DOI

    Scopus

    127
    Citation
    (Scopus)
  • SUZAKU OBSERVATIONS OF THE DIFFUSE X-RAY EMISSION ACROSS THE FERMI BUBBLES' EDGES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, L. Stawarz, Y. Takahashi, Y. Takeuchi, H. Tsunemi, M. Kimura, Y. Takei, C. C. Cheung, Y. Inoue, T. Nakamori

    ASTROPHYSICAL JOURNAL   779 ( 1 ) 57 - 72  2013.12  [Refereed]

     View Summary

    We present Suzaku X-ray observations along two edge regions of the Fermi Bubbles, with eight similar or equal to 20 ks pointings across the northern part of the North Polar Spur (NPS) surrounding the north bubble and six across the southernmost edge of the south bubble. After removing compact X-ray features, diffuse X-ray emission is clearly detected and is well reproduced by a three-component spectral model consisting of unabsorbed thermal emission (temperature kT similar or equal to 0.1 keV) from the Local Bubble, absorbed kT similar or equal to 0.3 keV thermal emission related to the NPS and/or Galactic halo (GH), and a power-law component at a level consistent with the cosmic X-ray background. The emission measure (EM) of the 0.3 keV plasma decreases by similar or equal to 50% toward the inner regions of the northeast bubble, with no accompanying temperature change. However, such a jump in the EM is not clearly seen in the south bubble data. While it is unclear whether the NPS originates from a nearby supernova remnant or is related to previous activity within or around the Galactic center, our Suzaku observations provide evidence that suggests the latter scenario. In the latter framework, the presence of a large amount of neutral matter absorbing the X-ray emission as well as the existence of the kT similar or equal to 0.3 keV gas can be naturally interpreted as a weak shock driven by the bubbles' expansion in the surrounding medium, with velocity v(exp) similar or equal to 300 km s(-1) (corresponding to shock Mach number M similar or equal to 1.5), compressing the GH gas to form the NPS feature. We also derived an upper limit for any non-thermal X-ray emission component associated with the bubbles and demonstrate that, in agreement with the aforementioned findings, the non-thermal pressure and energy estimated from a one-zone leptonic model of its broadband spectrum, are in rough equilibrium with that of the surrounding thermal plasma.

    DOI

    Scopus

    100
    Citation
    (Scopus)
  • Erratum: Fermi large area telescope study of cosmic-rays and the interstellar medium in nearby molecular clouds (ApJ (2012) 755 (22))

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, G. Busetto, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, Y. Fukazawa, Y. Fukui, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, K. Hayashi, D. Horan, X. Hou, R. E. Hughes, R. Itoh, M. S. Jackson, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, P. Martin, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia

    Astrophysical Journal   778 ( 1 )  2013.11

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    6
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  • The First Fermi-LAT Gamma-Ray Burst Catalog

    Ackermann M, Ajello M, Asano K, Axelsson M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Bhat P.~N, Bissaldi E, Bloom E.~D, Bonamente E, Bonnell J, Bouvier A, Brandt T.~J, Bregeon J, Brigida M, Bruel P, Buehler R, Burgess J.~M, Buson S, Byrne D, Caliandro G.~A, Cameron R.~A, Caraveo P.~A, Cecchi C, Charles E, Chaves R.~C.~G, Chekhtman A, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Connaughton V, Conrad J, Cutini S, D'Ammando F, de Angelis A, de Palma F, Dermer C.~D, Desiante R, Digel S.~W, Dingus B.~L, Di Venere L, Drell P.~S, Drlica-Wagner A, Dubois R, Favuzzi C, Ferrara E.~C, Fitzpatrick G, Foley S, Franckowiak A, Fukazawa Y, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Goldstein A, Granot J, Grenier I.~A, Grove J.~E, Gruber D, Guiriec S, Hadasch D, Hanabata Y, Hayashida M, Horan D, Hou X, Hughes R.~E, Inoue Y, Jackson M.~S, Jogler T, J{\'o}hannesson G, Johnson A.~S, Johnson W.~N, Kamae T, Kataoka J, Kawano T, Kippen R.~M, Kn{\"o}dlseder J, Kocevski D, Kouveliotou C, Kuss M, Lande J, Larsson S, Latronico L, Lee S.-H, Longo F, Loparco F, Lovellette M.~N, Lubrano P, Massaro F, Mayer M, Mazziotta M.~N, McBreen S, McEnery J.~E, McGlynn S, Michelson P.~F, Mizuno T, Moiseev A.~A, Monte C, Monzani M.~E, Moretti E, Morselli A, Murgia S, Nemmen R, Nuss E, Nymark T, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, Paciesas W.~S, Paneque D, Panetta J.~H, Pelassa V, Perkins J.~S, Pesce-Rollins M, Piron F, Pivato G, Porter T.~A, Preece R, Racusin J.~L, Rain{\`o} S, Rando R, Rau A, Razzano M, Razzaque S, Reimer A, Reimer O, Reposeur T, Ritz S, Romoli C, Roth M, Ryde F, Saz Parkinson P.~M, Schalk T.~L, Sgr{\`o} C, Siskind E.~J, Sonbas E, Spandre G, Spinelli P, Suson D.~J, Tajima H, Takahashi H, Takeuchi Y, Tanaka Y, Thayer J.~G, Thayer J.~B, Thompson D.~J, Tibaldo L, Tierney D, Tinivella M, Torres D.~F, Tosti G, Troja E, Tronconi V, Usher T.~L, Vandenbroucke J, van der Horst A.~J, Vasileiou V, Vianello G, Vitale V, von Kienlin A, Winer B.~L, Wood K.~S, Wood M, Xiong S, Yang Z

    The Astrophysical Journal Supplement   209 ( 1 ) 11  2013.11  [Refereed]

     View Summary

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (≳ 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ∼20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model. © 2013. The American Astronomical Society. All rights reserved.

    DOI

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    270
    Citation
    (Scopus)
  • THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS

    A. A. Abdo, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, A. Belfiore, R. Bellazzini, B. Bhattacharyya, E. Bissaldi, E. D. Bloom, E. Bonamente, E. Bottacini, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, M. Burgay, T. H. Burnett, G. Busetto, S. Buson, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Oe . Celik, E. Charles, S. Chaty, R. C. G. Chaves, A. Chekhtman, A. W. Chen, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, M. E. DeCesar, A. De Luca, P. R. Den Hartog, F. De Palma, C. D. Dermer, G. Desvignes, S. W. Digel, L. Di Venere, P. S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. M. Espinoza, L. Falletti, C. Favuzzi, E. C. Ferrara, W. B. Focke, A. Franckowiak, P. C. C. Freire, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, J. Hessels, J. Hewitt, A. B. Hill, D. Horan, X. Hou, R. E. Hughes, M. S. Jackson, G. H. Janssen, T. Jogler, G. Johannesson, R. P. Johnson, A. S. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, J. Kataoka, M. Keith, M. Kerr, J. Knoedlseder, M. Kramer, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, A. G. Lyne, R. N. Manchester, M. Marelli, F. Massaro, M. Mayer, M. N. Mazziotta, J. E. McEnery, M. A. McLaughlin, J. Mehault, P. F. Michelson, R. P. Mignani, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, R. Nemmen, E. Nuss, M. Ohno, T. Ohsugi, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, J. S. Perkins, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, H. J. Pletsch, T. A. Porter, A. Possenti, S. Raino, R. Rando, S. M. Ransom, P. S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, N. Renault, T. Reposeur, S. Ritz, R. W. Romani, M. Roth, R. Rousseau, J. Roy, J. Ruan, A. Sartori, P. M. Saz Parkinson, J. D. Scargle, A. Schulz, C. Sgro, R. Shannon, E. J. Siskind, D. A. Smith, G. Spandre, P. Spinelli, B. W. Stappers, A. W. Strong, D. J. Suson, H. Takahashi, J. G. Thayer, J. B. Thayer, G. Theureau, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, M. Tinivella, D. F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, V. Vasileiou, C. Venter, G. Vianello, V. Vitale, N. Wang, P. Weltevrede, B. L. Winer, M. T. Wolff, D. L. Wood, K. S. Wood, M. Wood, Z. Yang

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   208 ( 2 ) 17  2013.10  [Refereed]

     View Summary

    This catalog summarizes 117 high-confidence &gt;= 0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

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    737
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  • MULTIBAND DIAGNOSTICS OF UNIDENTIFIED 1FGL SOURCES WITH SUZAKU AND SWIFT X-RAY OBSERVATIONS

    Y. Takeuchi, J. Kataoka, K. Maeda, Y. Takahashi, T. Nakamori, M. Tahara

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   208 ( 2 ) 25 - 57  2013.10  [Refereed]

     View Summary

    We have analyzed all the archival X-ray data of 134 unidentified (unID) gamma-ray sources listed in the first Fermi/LAT (1FGL) catalog and subsequently followed up by the Swift/XRT. We constructed the spectral energy distributions (SEDs) from radio to gamma-rays for each X-ray source detected, and tried to pick up unique objects that display anomalous spectral signatures. In these analyses, we target all the 1FGL unID sources, using updated data from the second Fermi/LAT (2FGL) catalog on the Large Area Telescope (LAT) position and spectra. We found several potentially interesting objects, particularly three sources, 1FGL J0022.2-1850, 1FGL J0038.0+1236, and 1FGL J0157.0-5259, which were then more deeply observed with Suzaku as a part of an AO-7 program in 2012. We successfully detected an X-ray counterpart for each source whose X-ray spectra were well fitted by a single power-law function. The positional coincidence with a bright radio counterpart (currently identified as an active galactic nucleus, AGN) in the 2FGL error circles suggests these sources are definitely the X-ray emission from the same AGN, but their SEDs show a wide variety of behavior. In particular, the SED of 1FGL J0038.0+1236 is not easily explained by conventional emission models of blazars. The source 1FGL J0022.2-1850 may be in a transition state between a low-frequency peaked and a high-frequency peaked BL Lac object, and 1FGL J0157.0-5259 could be a rare kind of extreme blazar. We discuss the possible nature of these three sources observed with Suzaku, together with the X-ray identification results and SEDs of all 134 sources observed with the Swift/XRT.

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    29
    Citation
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  • Development of a high-sensitivity, handy Compton camera for fast gamma-ray imaging

    KATAOKA Jun, NISHIYAMA Toru, FUJITA Takuya, TAKEUCHI Kenshiro, KISHIMOTO Aya, OHSUKA Shinji, NAKAMURA Shigeyuki, HIRAYANAGI Masato, ADACHI Shunsuke, UCHIYAMA Tetsuya, KATO Takuya, SUZUKI Hiroki

      2013 ( 1 ) 1 - 6  2013.09

    CiNii

  • Erratum: Constraints on the cosmic-ray density gradient beyond the solar circle from fermi γ-ray observations of the third galactic quadrant (Astrophysical Journal (2011) 726 (81))

    M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, F. De Palma, S.W. Digel, P.S. Drell, R. Dubois, C. Favuzzi, E.C. Ferrara, W.B. Focke, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, M. Hayashida, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Llena-Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, P. Martin, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, J. Ripken, T. Sada, H.F.-W. Sadrozinski, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.E. Vladimirov, A.P. Waite, P. Wang, K.S. Wood, Z. Yang, M. Ziegler

    Astrophysical Journal   772 ( 2 )  2013.08  [Refereed]

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    2
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  • X-RAY AND RADIO FOLLOW-UP OBSERVATIONS OF HIGH-REDSHIFT BLAZAR CANDIDATES IN THE FERMI-LAT UNASSOCIATED SOURCE POPULATION

    Y. Takahashi, J. Kataoka, K. Niinuma, M. Honma, Y. Inoue, T. Totani, S. Inoue, T. Nakamori, K. Maeda

    ASTROPHYSICAL JOURNAL   773 ( 1 ) 36 - 46  2013.08  [Refereed]

     View Summary

    We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548, selected as candidates for high-redshift blazars from unassociated sources in the Fermi Large Area Telescope Second Source Catalog. We utilize the Suzaku satellite and the VLBI Exploration of Radio Astrometry (VERA) telescopes for X-ray and radio observations, respectively. For 2FGL J0923.5+1508, a possible radio counterpart NVSS J092357+150518 is found at 1.4 GHz from an existing catalog, but we do not detect any X-ray emission from it and derive a flux upper limit F2-8 (keV) &lt; 1.37 x 10(-14) erg cm(-2) s(-1). Radio observations at 6.7 GHz also result in an upper limit of S-6.7 (GHz) &lt; 19 mJy, implying a steep radio spectrum that is not expected for a blazar. On the other hand, we detect X-rays from NVSS J150229+555204, the potential 1.4 GHz radio counterpart of 2FGL J1502.1+5548. The X-ray spectrum can be fitted with an absorbed power-law model with a photon index gamma = 1.8(-0.2)(+0.3) and the unabsorbed flux is F2-8 (keV) = 4.3(-1.0)(+1.1) x 10(-14) erg cm(-2) s(-1). Moreover, we detect unresolved radio emission at 6.7 GHz with flux S-6.7 (GHz) = 30.1 mJy, indicating a compact, flat-spectrum radio source. If NVSS J150229+555204 is indeed associated with 2FGL J1502.1+5548, then we find that its multiwavelength spectrum is consistent with a blazar at redshift z similar to 3-4.

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  • Development of Radiation-hardened Multi Pixel Photon Counters

    Nakamori, T, Kurei, Y, Takeuchi, K, Saito, T, Kataoka, J, Fujita, T, Kato, T, Sato, K, Yamada, R, Kawabata, N, Kokubun, M

    Proceedings of 33rd International Cosmic Ray Conference   2013-October  2013.07

     View Summary

    We developed several kinds of trial radiation-hardened MPPC models by changing structures; targeting future space applications for gamma-ray detectors. We produced two sample packages with 15 µ-type 1×1 mm2 MPPC elements for every 9 prototypes and then irradiated 150 MeV protons up to 10- and 100 krad for respective samples. We also used 15-, 25-, 50- and 100-µm-type MPPCs with the current design as controls. We evaluated the radiation tolerance mainly by increasing ratio of post-irradiation dark currents. Consequently we found that all trial models achieved significantly improved radiation tolerance peaking at a factor of 7−8 in the best case. We also present differences among control samples due to the various pixel sizes.

  • The Fermi all-sky variability analysis: A list of flaring gamma-ray sources and the search for transients in our galaxy

    M. Ackermann, M. Ajello, A. Albert, A. Allafort, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, E. Bottacini, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, M. Dalton, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, L. Di Venere, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, J. Hewitt, A. B. Hill, D. Horan, X. Hou, R. E. Hughes, Y. Inoue, M. S. Jackson, T. Jogler, G. Jóhannesson, W. N. Johnson, T. Kamae, J. Kataoka, T. Kawano, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno

    Astrophysical Journal   771 ( 1 )  2013.07

     View Summary

    In this paper, we present the Fermi All-sky Variability Analysis (FAVA), a tool to systematically study the variability of the gamma-ray sky measured by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. For each direction on the sky, FAVA compares the number of gamma-rays observed in a given time window to the number of gamma-rays expected for the average emission detected from that direction. This method is used in weekly time intervals to derive a list of 215 flaring gamma-ray sources. We proceed to discuss the 27 sources found at Galactic latitudes smaller than 10° and show that, despite their low latitudes, most of them are likely of extragalactic origin. © 2013. The American Astronomical Society. All rights reserved.

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  • High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

    T. Kato, J. Kataoka, T. Nakamori, A. Kishimoto, S. Yamamoto, K. Sato, Y. Ishikawa, K. Yamamura, N. Kawabata, H. Ikeda, K. Kamada

    JOURNAL OF INSTRUMENTATION   8 ( 5 ) P05022  2013.05  [Refereed]

     View Summary

    We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4x4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5x10(5) at + 20 degrees C, gain fluctuation over the entire MPPC device is only +/- 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to &lt;= 400 kcps per channel. We selected Ce-doped (Lu, Y)(2)(SiO4)O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated into 15x15 matrices of 0.5x0.5 mm(2) pixels. The Ce: LYSO and Ce: GAGG scintillator matrices were assembled into phosphor sandwich (phoswich) detectors, and then coupled to the MPPC array along with an acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a Na-22 point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

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  • GIANT LOBES OF CENTAURUS A RADIO GALAXY OBSERVED WITH THE SUZAKU X-RAY SATELLITE

    Stawarz, L, Tanaka, Y. T, Madejski, G, O'Sullivan, S. P, Cheung, C. C, Feain, I. J, Fukazawa, Y, Gandhi, P, Hardcastle, M. J, Kataoka, J

    ASTROPHYSICAL JOURNAL   766 ( 1 )  2013.03  [Refereed]

     View Summary

    We report on Suzaku observations of selected regions within the southern giant lobe of the radio galaxy Centaurus A. In our analysis we focus on distinct X-ray features detected with the X-ray Imaging Spectrometer within the range 0.5-10 keV, some of which are likely associated with fine structure of the lobe revealed by recent high-quality radio intensity and polarization maps. With the available photon statistics, we find that the spectral properties of the detected X-ray features are equally consistent with thermal emission from hot gas with temperatures kT &gt; 1 keV, or with a power-law radiation continuum characterized by photon indices Gamma similar to 2.0 +/- 0.5. However, the plasma parameters implied by these different models favor a synchrotron origin for the analyzed X-ray spots, indicating that a very efficient acceleration of electrons up to greater than or similar to 10 TeV energies is taking place within the giant structure of Centaurus A, albeit only in isolated and compact regions associated with extended and highly polarized radio filaments. We also present a detailed analysis of the diffuse X-ray emission filling the whole field of view of the instrument, resulting

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  • Introducing the CTA concept

    Acharya, B. S., Actis, M., Aghajani, T., Agnetta, G., Aguilar, J., Aharonian, F., Ajello, M., Akhperjanian, A., Alcubierre, M., Aleksić, J., Alfaro, R., Aliu, E., Allafort, A. J., Allan, D., Allekotte, I., Amato, E., Anderson, J., Angüner, E. O., Antonelli, L. A., Antoranz, P. Aravantinos, A., Arlen, T., Armstrong, T., Arnaldi, H., Arrabito, L., Asano, K., Ashton, T., Asorey, H. G., Awane, Y., Baba, H., Babic, A., Baby, N., Bähr, J., Bais, A., Baixeras, C., Bajtlik, S., Balbo, M., Balis, D., Balkowski, C., Bamba, A., Bandiera, R., Barber, A., Barbier, C., Barceló, M., Barnacka, A., Barnstedt, J., Barres de Almeida, U., Barrio, J. A., Basili, A., Basso, S., Bastieri, D., Bauer, C., Baushev, A., Becerra, J., Becherini, Y., Bechtol, K. C., Becker Tjus, J., Beckmann, V., Bednarek, W., Behera, B., Belluso, M., Benbow, W., Berdugo, J., Berger, K., Bernard, F., Bernardino, T., Bernlöhr, K., Bhat, N., Bhattacharyya, S., Bigongiari, C., Biland, A., Billotta, S., Bird, T., Birsin, E., Bissaldi, E., Biteau, J., Bitossi, M., Blake, S., Blanch Bigas, O., Blasi, P., Bobkov, A., Boccone, V., Boettcher, M., Bogacz, L., Bogart, J., Bogdan, M., Boisson, C., Boix Gargallo, J., Bolmont, J., Bonanno, G., Bonardi, A., Bonev, T., Bonifacio, P., Bonnoli, G., Bordas, P., Borgland, A., Borkowski, J., Bose, R., Botner, O., Bottani, A., Bouchet, L., Bourgeat, M., Boutonnet, C., Bouvier, A., Brau-Nogué, S., Braun, I., Bretz, T., Briggs, M., Bringmann, T., Brook, P., Brun, P., Brunetti, L., Buanes, T., Buckley, J., Buehler, R., Bugaev, V., Bulgarelli, A., Bulik, T., Busetto, G., Buson, S., Byrum, K., Cailles, M., Cameron, R., Camprecios, J., Canestrari, R., Cantu, S., Capalbi, M., Caraveo, P., Carmona, E., Carosi, A., Carr, J., Carton, P. -H., Casanova, S., Casiraghi, M., Catalano, O., Cavazzani, S., Cazaux, S., Cerruti, M., Chabanne, E., Chadwick, P., Champion, C., Chen, A., Chiang, J., Chiappetti, L., Chikawa, M., Chitnis, V. R., Chollet, F., Chudoba, J., Cieślar, M., Cillis, A., Cohen-Tanugi, J., Colafrancesco, S., Colin, P., Colome, J., Colonges, S., Compin, M., Conconi, P., Conforti, V., Connaughton, V., Conrad, J., Contreras, J. L., Coppi, P., Corona, P., Corti, D., Cortina, J., Cossio, L., Costantini, H., Cotter, G., Courty, B., Couturier, S., Covino, S., Crimi, G., Criswell, S. J., Croston, J., Cusumano, G., Dafonseca, M., Dale, O., Daniel, M., Darling, J., Davids, I., Dazzi, F., De Angelis, A., De Caprio, V., De Frondat, F., de Gouveia Dal Pino, E. M., de la Calle, I., De La Vega, G. A., de los Reyes Lopez, R., De Lotto, B., De Luca, A., de Mello Neto, J. R. T., de Naurois, M., de Oliveira, Y., de Oña Wilhelmi, E., de Souza, V., Decerprit, G., Decock, G., Deil, C., Delagnes, E., Deleglise, G., Delgado, C., Della Volpe, D., Demange, P., Depaola, G., Dettlaff, A., Di Paola, A., Di Pierro, F., Díaz, C., Dick, J., Dickherber, R., Dickinson, H., Diez-Blanco, V., Digel, S., Dimitrov, D., Disset, G., Djannati-Ataï, A., Doert, M., Dohmke, M., Domainko, W., Dominis Prester, D., Donat, A., Dorner, D., Doro, M., Dournaux, J. -L., Drake, G., Dravins, D., Drury, L., Dubois, F., Dubois, R., Dubus, G., Dufour, C., Dumas, D., Dumm, J., Durand, D., Dyks, J., Dyrda, M., Ebr, J., Edy, E., Egberts, K., Eger, P., Einecke, S., Eleftheriadis, C., Elles, S., Emmanoulopoulos, D., Engelhaupt, D., Enomoto, R., Ernenwein, J. -P., Errando, M., Etchegoyen, A., Evans, P., Falcone, A., Fantinel, D., Farakos, K., Farnier, C., Fasola, G., Favill, B., Fede, E., Federici, S., Fegan, S., Feinstein, F., Ferenc, D., Ferrando, P., Fesquet, M., Fiasson, A., Fillin-Martino, E., Fink, D., Finley, C., Finley, J. P., Fiorini, M., Firpo Curcoll, R., Flores, H., Florin, D., Focke, W., Föhr, C., Fokitis, E., Font, L., Fontaine, G., Fornasa, M., Förster, A., Fortson, L., Fouque, N., Franckowiak, A., Fransson, C., Fraser, G., Frei, R., Albuquerque, I. F. M., Fresnillo, L., Fruck, C., Fujita, Y., Fukazawa, Y., Fukui, Y., Funk, S., Gäbele, W., Gabici, S., Gabriele, R., Gadola, A., Galante, N., Gall, D., Gallant, Y., Gámez-García, J., García, B., Garcia López, R., Gardiol, D., Garrido, D., Garrido, L., Gascon, D., Gaug, M., Gaweda, J., Gebremedhin, L., Geffroy, N., Gerard, L., Ghedina, A., Ghigo, M., Giannakaki, E., Gianotti, F., Giarrusso, S., Giavitto, G., Giebels, B., Gika, V., Giommi, P., Girard, N., Giro, E., Giuliani, A., Glanzman, T., Glicenstein, J. -F., Godinovic, N., Golev, V., Gomez Berisso, M., Gómez-Ortega, J., Gonzalez, M. M., González, A., González, F., González Muñoz, A., Gothe, K. S., Gougerot, M., Graciani, R., Grandi, P., Grañena, F., Granot, J., Grasseau, G., Gredig, R., Green, A., Greenshaw, T., Grégoire, T., Grimm, O., Grube, J., Grudzinska, M., Gruev, V., Grünewald, S., Grygorczuk, J., Guarino, V., Gunji, S., Gyuk, G., Hadasch, D., Hagiwara, R., Hahn, J., Hakansson, N., Hallgren, A., Hamer Heras, N., Hara, S., Hardcastle, M. J., Harris, J., Hassan, T., Hatanaka, K., Haubold, T., Haupt, A., Hayakawa, T., Hayashida, M., Heller, R., Henault, F., Henri, G., Hermann, G., Hermel, R., Herrero, A., Hidaka, N., Hinton, J., Hoffmann, D., Hofmann, W., Hofverberg, P., Holder, J., Horns, D., Horville, D., Houles, J., Hrabovsky, M., Hrupec, D., Huan, H., Huber, B., Huet, J. -M., Hughes, G., Humensky, T. B., Huovelin, J., Ibarra, A., Illa, J. M., Impiombato, D., Incorvaia, S., Inoue, S., Inoue, Y., Ioka, K., Ismailova, E., Jablonski, C., Jacholkowska, A., Jamrozy, M., Janiak, M., Jean, P., Jeanney, C., Jimenez, J. J., Jogler, T., Johnson, T., Journet, L., Juffroy, C., Jung, I., Kaaret, P., Kabuki, S., Kagaya, M., Kakuwa, J., Kalkuhl, C., Kankanyan, R., Karastergiou, A., Kärcher, K., Karczewski, M., Karkar, S., Kasperek, J., Kastana, D., Katagiri, H., Kataoka, J., Katarzyński, K., Katz, U., Kawanaka, N., Kellner-Leidel, B., Kelly, H., Kendziorra, E., Khélifi, B., Kieda, D. B., Kifune, T., Kihm, T., Kishimoto, T., Kitamoto, K., Kluźniak, W., Knapic, C., Knapp, J., Knödlseder, J., Köck, F., Kocot, J., Kodani, K., Köhne, J. -H., Kohri, K., Kokkotas, K., Kolitzus, D., Komin, N., Kominis, I., Konno, Y., Köppel, H., Korohoda, P., Kosack, K., Koss, G., Kossakowski, R., Kostka, P., Koul, R., Kowal, G., Koyama, S., Kozioł, J., Krähenbühl, T., Krause, J., Krawzcynski, H., Krennrich, F., Krepps, A., Kretzschmann, A., Krobot, R., Krueger, P., Kubo, H., Kudryavtsev, V. A., Kushida, J., Kuznetsov, A., La Barbera, A., La Palombara, N., La Parola, V., La Rosa, G., Lacombe, K., Lamanna, G., Lande, J., Languignon, D., Lapington, J., Laporte, P., Lavalley, C., Le Flour, T., Le Padellec, A., Lee, S. -H., Lee, W. H., Leigui de Oliveira, M. A., Lelas, D., Lenain, J. -P., Leopold, D. J., Lerch, T., Lessio, L., Lieunard, B., Lindfors, E., Liolios, A., Lipniacka, A., Lockart, H., Lohse, T., Lombardi, S., Lopatin, A., Lopez, M., López-Coto, R., López-Oramas, A., Lorca, A., Lorenz, E., Lubinski, P., Lucarelli, F., Lüdecke, H., Ludwin, J., Luque-Escamilla, P. L., Lustermann, W., Luz, O., Lyard, E., Maccarone, M. C., Maccarone, T. J., Madejski, G. M., Madhavan, A., Mahabir, M., Maier, G., Majumdar, P., Malaguti, G., Maltezos, S., Manalaysay, A., Mancilla, A., Mandat, D., Maneva, G., Mangano, A., Manigot, P., Mannheim, K., Manthos, I., Maragos, N., Marcowith, A., Mariotti, M., Marisaldi, M., Markoff, S., Marszałek, A., Martens, C., Martí, J., Martin, J. -M., Martin, P., Martínez, G., Martínez, F., Martínez, M., Masserot, A., Mastichiadis, A., Mathieu, A., Matsumoto, H., Mattana, F., Mattiazzo, S., Maurin, G., Maxfield, S., Maya, J., Mazin, D., Mc Comb, L., McCubbin, N., McHardy, I., McKay, R., Medina, C., Melioli, C., Melkumyan, D., Mereghetti, S., Mertsch, P., Meucci, M., Michałowski, J., Micolon, P., Mihailidis, A., Mineo, T., Minuti, M., Mirabal, N., Mirabel, F., Miranda, J. M., Mirzoyan, R., Mizuno, T., Moal, B., Moderski, R., Mognet, I., Molinari, E., Molinaro, M., Montaruli, T., Monteiro, I., Moore, P., Moralejo Olaizola, A., Mordalska, M., Morello, C., Mori, K., Mottez, F., Moudden, Y., Moulin, E., Mrusek, I., Mukherjee, R., Munar-Adrover, P., Muraishi, H., Murase, K., Murphy, A., Nagataki, S., Naito, T., Nakajima, D., Nakamori, T., Nakayama, K., Naumann, C., Naumann, D., Naumann-Godo, M., Nayman, P., Nedbal, D., Neise, D., Nellen, L., Neustroev, V., Neyroud, N., Nicastro, L., Nicolau-Kukliński, J., Niedźwiecki, A., Niemiec, J., Nieto, D., Nikolaidis, A., Nishijima, K., Nolan, S., Northrop, R., Nosek, D., Nowak, N., Nozato, A., O'Brien, P., Ohira, Y., Ohishi, M., Ohm, S., Ohoka, H., Okuda, T., Okumura, A., Olive, J. -F., Ong, R. A., Orito, R., Orr, M., Osborne, J., Ostrowski, M., Otero, L. A., Otte, N., Ovcharov, E., Oya, I., Ozieblo, A., Padilla, L., Paiano, S., Paillot, D., Paizis, A., Palanque, S., Palatka, M., Pallota, J., Panagiotidis, K., Panazol, J. -L., Paneque, D., Panter, M., Paoletti, R., Papayannis, A., Papyan, G., Paredes, J. M., Pareschi, G., Parks, G., Parraud, J. -M., Parsons, D., Paz Arribas, M., Pech, M., Pedaletti, G., Pelassa, V., Pelat, D., Perez, M. d. C., Persic, M., Petrucci, P. -O., Peyaud, B., Pichel, A., Pita, S., Pizzolato, F., Platos, Ł., Platzer, R., Pogosyan, L., Pohl, M., Pojmanski, G., Ponz, J. D., Potter, W., Poutanen, J., Prandini, E., Prast, J., Preece, R., Profeti, F., Prokoph, H., Prouza, M., Proyetti, M., Puerto-Gimenez, I., Pühlhofer, G., Puljak, I., Punch, M., Pyzioł, R., Quel, E. J., Quinn, J., Quirrenbach, A., Racero, E., Rajda, P. J., Ramon, P., Rando, R., Rannot, R. C., Rataj, M., Raue, M., Reardon, P., Reimann, O., Reimer, A., Reimer, O., Reitberger, K., Renaud, M., Renner, S., Reville, B., Rhode, W., Ribó, M., Ribordy, M., Richer, M. G., Rico, J., Ridky, J., Rieger, F., Ringegni, P., Ripken, J., Ristori, P. R., Riviére, A., Rivoire, S., Rob, L., Roeser, U., Rohlfs, R., Rojas, G., Romano, P., Romaszkan, W., Romero, G. E., Rosen, S., Rosier Lees, S., Ross, D., Rouaix, G., Rousselle, J., Rousselle, S., Rovero, A. C., Roy, F., Royer, S., Rudak, B., Rulten, C., Rupiński, M., Russo, F., Ryde, F., Sacco, B., Saemann, E. O., Saggion, A., Sahakian, V., Saito, K., Saito, T., Saito, Y., Sakaki, N., Sakonaka, R., Salini, A., Sanchez, F., Sanchez-Conde, M., Sandoval, A., Sandaker, H., Sant'Ambrogio, E., Santangelo, A., Santos, E. M., Sanuy, A., Sapozhnikov, L., Sarkar, S., Sartore, N., Sasaki, H., Satalecka, K., Sawada, M., Scalzotto, V., Scapin, V., Scarcioffolo, M., Schafer, J., Schanz, T., Schlenstedt, S., Schlickeiser, R., Schmidt, T., Schmoll, J., Schovanek, P., Schroedter, M., Schultz, C., Schultze, J., Schulz, A., Schure, K., Schwab, T., Schwanke, U., Schwarz, J., Schwarzburg, S., Schweizer, T., Schwemmer, S., Segreto, A., Seiradakis, J. -H., Sembroski, G. H., Seweryn, K., Sharma, M., Shayduk, M., Shellard, R. C., Shi, J., Shibata, T., Shibuya, A., Shum, E., Sidoli, L., Sidz, M., Sieiro, J., Sikora, M., Silk, J., Sillanpää, A., Singh, B. B., Sitarek, J., Skole, C., Smareglia, R., Smith, A., Smith, D., Smith, J., Smith, N., Sobczyńska, D., Sol, H., Sottile, G., Sowiński, M., Spanier, F., Spiga, D., Spyrou, S., Stamatescu, V., Stamerra, A., Starling, R., Stawarz, Ł., Steenkamp, R., Stegmann, C., Steiner, S., Stergioulas, N., Sternberger, R., Sterzel, M., Stinzing, F., Stodulski, M., Straumann, U., Strazzeri, E., Stringhetti, L., Suarez, A., Suchenek, M., Sugawara, R., Sulanke, K. -H., Sun, S., Supanitsky, A. D., Suric, T., Sutcliffe, P., Sykes, J., Szanecki, M., Szepieniec, T., Szostek, A., Tagliaferri, G., Tajima, H., Takahashi, H., Takahashi, K., Takalo, L., Takami, H., Talbot, G., Tammi, J., Tanaka, M., Tanaka, S., Tasan, J., Tavani, M., Tavernet, J. -P., Tejedor, L. A., Telezhinsky, I., Temnikov, P., Tenzer, C., Terada, Y., Terrier, R., Teshima, M., Testa, V., Tezier, D., Thuermann, D., Tibaldo, L., Tibolla, O., Tiengo, A., Tluczykont, M., Todero Peixoto, C. J., Tokanai, F., Tokarz, M., Toma, K., Torii, K., Tornikoski, M., Torres, D. F., Torres, M., Tosti, G., Totani, T., Toussenel, F., Tovmassian, G., Travnicek, P., Trifoglio, M., Troyano, I., Tsinganos, K., Ueno, H., Umehara, K., Upadhya, S. S., Usher, T., Uslenghi, M., Valdes-Galicia, J. F., Vallania, P., Vallejo, G., van Driel, W., van Eldik, C., Vandenbrouke, J., Vanderwalt, J., Vankov, H., Vasileiadis, G., Vassiliev, V., Veberic, D., Vegas, I., Vercellone, S., Vergani, S., Veyssiére, C., Vialle, J. P., Viana, A., Videla, M., Vincent, P., Vincent, S., Vink, J., Vlahakis, N., Vlahos, L., Vogler, P., Vollhardt, A., von Gunten, H. -P., Vorobiov, S., Vuerli, C., Waegebaert, V., Wagner, R., Wagner, R. G., Wagner, S., Wakely, S. P., Walter, R., Walther, T., Warda, K., Warwick, R., Wawer, P., Wawrzaszek, R., Webb, N., Wegner, P., Weinstein, A., Weitzel, Q., Welsing, R., Werner, M., Wetteskind, H., White, R., Wierzcholska, A., Wiesand, S., Wilkinson, M., Williams, D. A., Willingale, R., Winiarski, K., Wischnewski, R., Wiśniewski, Ł., Wood, M., Wörnlein, A., Xiong, Q., Yadav, K. K., Yamamoto, H., Yamamoto, T., Yamazaki, R., Yanagita, S., Yebras, J. M., Yelos, D., Yoshida, A., Yoshida, T., Yoshikoshi, T., Zabalza, V., Zacharias, M., Zajczyk, A., Zanin, R., Zdziarski, A., Zech, A., Zhao, A., Zhou, X., Ziętara, K., Ziolkowski, J., Ziółkowski, P., Zitelli, V., Zurbach, C., Żychowski, P., CTA Consortium

    Astroparticle Physics   43   3 - 18  2013.03  [Refereed]

     View Summary

    The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. © 2013 Elsevier B.V. All rights reserved.

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  • Determination of the point-spread function for the fermi large area telescope from on-orbit data and limits on pair halos of active galactic nuclei

    M. Ackermann, M. Ajello, A. Allafort, K. Asano, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, G. Busetto, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, S. Cutini, F. D'Ammando, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, X. Hou, R.E. Hughes, M.S. Jackson, T. Jogler, G. Jóhannesson, R.P. Johnson, A.S. Johnson, T. Kamae, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, C. Lavalley, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, W. McConville, J.E. McEnery, J. Mehault, P.F. Michelson, R.P. Mignani, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, R. Nemmen, S. Nishino, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, V. Pelassa, J.S. Perkins, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, H. Poon, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L.C. Reyes, S. Ritz, L.S. Rochester, C. Romoli, M. Roth, D.A. Sanchez, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, A. Snyder, G. Spandre, P. Spinelli, T.E. Stephens, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, M. Tinivella, G. Tosti, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. Von Kienlin, A.P. Waite, E. Wallace, P. Weltevrede, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, S. Zimmer

    Astrophysical Journal   765 ( 1 )  2013.03  [Refereed]

     View Summary

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to detect photons with energies from ≈20 MeV to >300 GeV. The pre-launch response functions of the LAT were determined through extensive Monte Carlo simulations and beam tests. The point-spread function (PSF) characterizing the angular distribution of reconstructed photons as a function of energy and geometry in the detector is determined here from two years of on-orbit data by examining the distributions of γ rays from pulsars and active galactic nuclei (AGNs). Above 3 GeV, the PSF is found to be broader than the pre-launch PSF. We checked for dependence of the PSF on the class of γ-ray source and observation epoch and found none. We also investigated several possible spatial models for pair-halo emission around BL Lac AGNs. We found no evidence for a component with spatial extension larger than the PSF and set upper limits on the amplitude of halo emission in stacked images of low- and high-redshift BL Lac AGNs and the TeV blazars 1ES0229+200 and 1ES0347-121. © 2013. The American Astronomical Society. All rights reserved.

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  • Radio-Quiet Millisecond Pulsars : Fermi Discovery of New Type Pulsars

    YATSU Yoichi, KAWAI Nobuyuki, KATAOKA Jun, TAKAHASHI Yosuke

      106 ( 4 ) 254 - 262  2013.03

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  • Detection of the characteristic pion-decay signature in supernova remnants

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, G. Busetto, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, S. Chaty, R.C.G. Chaves, A. Chekhtman, C.C. Cheung, J. Chiang, G. Chiaro, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Corbel, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, E.C. Ferrara, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, K. Hayashi, E. Hays, J.W. Hewitt, A.B. Hill, R.E. Hughes, M.S. Jackson, T. Jogler, G. Jóhannesson, A.S. Johnson, T. Kamae, J. Kataoka, J. Katsuta, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, G.M. Madejski, F. Massaro, M. Mayer, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, R.P. Mignani, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, R. Nemmen, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, D. Paneque, J.S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, S. Ritz, C. Romoli, M. Sánchez-Conde, A. Schulz, C. Sgrò, P.E. Simeon, E.J. Siskind, D.A. Smith, G. Spandre, P. Spinelli, F.W. Stecker, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, S.E. Thorsett, L. Tibaldo, O. Tibolla, M. Tinivella, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, M. Werner, B.L. Winer, K.S. Wood, M. Wood, R. Yamazaki, Z. Yang, S. Zimmer

    Science   339 ( 6121 ) 807 - 811  2013.02  [Refereed]

     View Summary

    Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.

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  • Development of ultra-fast ASIC for future PET scanners using TOF-capable MPPC detectors

    H. Matsuda, J. Kataoka, H. Ikeda, T. Kato, T. Anbe, S. Nakamura, Y. Ishikawa, K. Sato, K. Yamamura

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   699   211 - 215  2013.01  [Refereed]

     View Summary

    We have developed a front-end ASIC (MPPC32) intended for future PET scanners that offers time-of-flight (TOF) capability in conjunction with a multi-pixel photon counter (MPPC) array. The ASIC design is based on the open-IP project proposed by JAXA and was realized in TSMC 0.35-μm CMOS technology. The circuit comprises 32-channel, low impedance CMOS current conveyors (CCs) to effectively acquire fast MPPC signals. In order to precisely measure the coincidence timing of 511 keV gamma rays, the leading-edge method was employed instead of conventional zero-crossing measurement to discriminate signals. As a result, we obtained time jitter and walk measurement of 67 ps (FWHM) and 98 ps (within 511 keV±20%), respectively. Moreover, excellent energy resolutions of 9.8% (662 keV
    FWHM) and 10.5% (511 keV
    FWHM) were obtained by utilizing a 3×3 mm2 MPPC (of 50μm pitch) coupled with a Ce-doped LYSO (Ce:LYSO) crystal 3×3×10 mm3 in size. We finally report on the TOF measurements, and demonstrate that the MPPC32 developed here can be a promising device for future TOF-PET scanners using the MPPC array. © 2012 Elsevier B.V.

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    13
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  • CTA Report 58 : General Report

    Teshima Masahiro, the CTA Japan Consortium

    Meeting Abstracts of the Physical Society of Japan   68.2.1   103  2013

    DOI CiNii

  • Current status and optimization of handy compton camera using 3D position-sensitive scintillators

    Toru Nishiyama, Jun Kataoka, Aya Kishimoto, Takuya Fujita, Kenshiro Takeuchi, Shinji Ohsuka, Sigeyuki Nakamura, Syunsuke Adachi, Michito Hirayanagi, Tetsuya Uchiyama, Yoshitaka Ishikawa, Takuya Kato

    IEEE Nuclear Science Symposium Conference Record    2013

     View Summary

    After the Japanese nuclear disaster in 2011, a large amount of radioactive isotopes was released and still remains a serious problem in Japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighing only 1.9 kg and measuring just 14×14×15 cm3 in size. Despite its compactness, the camera realizes a wide 180° field of vision, Δθ ∼ 10°(FWHM) angular resolution, and offers excellent sensitivity that can image a hotspot producing a 5 μSv/h dose at a distance of three meters, every 10 sec. Our key technology using 3D position-sensitive scintillators coupled with thin monolithic MPPC arrays has made this innovation possible for the first time. In this paper, we present the detailed optimization and simulation of the Compton camera currently under production with Hamamatsu Photonics. © 2013 IEEE.

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    2
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  • Gamma-ray visualization module

    H. Suzuki, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, S. Ohsuka, K. Nakamoto, J. Kataoka, T. Nishiyama, T. Fujita, K. Takeuchi

    IEEE Nuclear Science Symposium Conference Record    2013

     View Summary

    Gamma ray cameras can easily locate radiation hotspots where decontamination is required. Among them, the Compton camera that utilizes the Compton scattering is compact and lightweight because no radiation shielding is required. We have developed a Compton camera for quick visualization of the radioactive contamination. It features high detection efficiency by utilizing gamma ray detectors which is a combination of Multi-Pixel Photon Counter (MPPC) array and Gadolinium Aluminum Gallium Garnet (GAGG) scintillator arrays. © 2013 IEEE.

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    4
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  • Stereo Compton cameras for the 3-D localization of radioactive isotopes optimized by Geant4

    K. Takeuchi, J. Kataoka, T. Nishiyama, T. Fujita, A. Kishimoto, S. Ohsuka, S. Nakamura, A. Adachi, M. Hirayanagi, T. Uchiyama, Y. Ishikawa, T. Kato

    IEEE Nuclear Science Symposium Conference Record    2013

     View Summary

    The Compton camera is a convenient tool used to visualize the distribution of radioisotopes that emit gamma rays. Following the nuclear disaster in Fukushima in 2011, there is a particularly urgent need to develop 'gamma cameras', which can visualize the distribution of such radioisotopes. In response, we propose a portable Compton camera, which comprises 3-D position-sensitive GAGG scintillators coupled with thin monolithic MPPC arrays. We report on the detailed optimization of the detector design, based on Geant4 simulation. The results show that detection efficiency reaches up to 0.54%, or more than 10 times that of other cameras being tested in Fukushima, along with a moderate angular resolution of 8.1° (FWHM). By applying the triangular surveying method, we also propose a new concept for the 'stereo' measurement of gamma rays by using two Compton cameras, thus enabling the 3-D positional measurement of radioactive isotopes for the first time. From one point source simulation data, we ensured that the source position and the distance to the same could be determined typically to within 2 meters' accuracy and we also confirmed that more than two sources are clearly separated by the event selection from two point sources of simulation data. © 2013 IEEE.

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    1
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  • Development of the photomultiplier-tube readout system for the CTA large size telescope

    H. Kubo, R. Paoletti, Y. Awane, A. Bamba, M. Barcelo, J. A. Barrio, O. Blanch, J. Boix, C. Delgado, D. Fink, D. Gascon, S. Gunji, R. Hagiwara, Y. Hanabata, K. Hatanaka, M. Hayashida, M. Ikeno, S. Kabuki, H. Katagiri, J. Kataoka, Y. Konno, S. Koyama, T. Kishimoto, J. Kushida, G. Martínez, S. Masuda, J. M. Miranda, R. Mirzoyan, T. Mizuno, T. Nagayoshi, D. Nakajima, T. Nakamori, H. Ohoka, A. Okumura, R. Orito, T. Saito, A. Sanuy, H. Sasaki, M. Sawada, T. Schweizer, R. Sugawara, K. H. Sulanke, H. Tajima, M. Tanaka, S. Tanaka, L. A. Tejedor, Y. Terada, M. Teshima, F. Tokanai, Y. Tsuchiya, T. Uchida, H. Ueno, K. Umehara, T. Yamamoto

    Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013   2013-October  2013

     View Summary

    We have developed a prototype of the photomultiplier tube (PMT) readout system for the Cherenkov Telescope Array (CTA) Large Size Telescope (LST). Two thousand PMTs along with their readout systems are arranged on the focal plane of each telescope, with one readout system per 7-PMT cluster. The Cherenkov light pulses generated by the air showers are detected by the PMTs and amplified in a compact, low noise and wide dynamic range gain block. The output of this block is then digitized at a sampling rate of the order of GHz using the Domino Ring Sampler DRS4, an analog memory ASIC developed at Paul Scherrer Institute. The sampler has 1,024 capacitors per channel and four channels are cascaded for increased depth. After a trigger is generated in the system, the charges stored in the capacitors are digitized by an external slow sampling ADC and then transmitted via Gigabit Ethernet. An onboard FPGA controls the DRS4, trigger threshold, and Ethernet transfer. In addition, the control and monitoring of the Cockcroft-Walton circuit that provides high voltage for the 7-PMT cluster are performed by the same FPGA. A prototype named Dragon has been developed that has successfully sampled PMT signals at a rate of 2 GHz, and generated single photoelectron spectra.

  • MAGIC and multi-wavelength observations of the radio galaxy NGC 1275

    Pierre Colin, Dorit Eisenacher, Dorothée Hildebrand, Elina Lindfors, Saverio Lombardi, Kari Nilsson, Serena Partini, Fabrizio Tavecchio, Fabio Zandanel, Barabara Balmaverde, Jun Kataoka, Rami Rekola, Yosuke Takahashi

    Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013   2013-October  2013

     View Summary

    The massive radio galaxy NGC 1275 at the center of the Perseus cluster is regularly observed with the MAGIC telescopes since 2009. The observation campaign (in stereoscopic mode) between August 2010 and February 2011 leads to the first detection of the source in very high energy (VHE, >100 GeV) γ rays. NGC 1275 is one of the few non-Blazar AGNs detected in this domain which is highly dominated by BL Lac objects. The proximity and the relatively large angle between the jet axis and the line of sight allow to resolve inner-jet structures with radio interferometry and to test non-thermal emission model for larger viewing angles. NGC 1275 is then a good laboratory to locate the γ -ray emission region and understand acceleration process at work in AGNs. Here we present the long term monitoring of NGC 1275 with MAGIC as well as with Fermi-LAT (in GeV band), KVA (optical) and VLBA (15 GHz). The multiwavelength lightcurves show a correlation between γ - ray, optical and a radio component of the inner-jet. We reconstructed the broad band spectral energy distributions (SED) of the source during two separated MAGIC campaigns which both lead to the detection of NGC 1275 in VHE. We applied a one-zone Synchrotron Self Compton model with a small Doppler factor (2) which can fit the SEDs and reproduces the optical/gamma correlation. Finally, we will discuss the validity of this simple model and the implication of our results for the AGN physics.

  • Fermi -LAT and Suzaku observations of the radio galaxy Centaurus B

    J. Katsuta, Y. T. Tanaka, L. Stawarz, S. P. O'Sullivan, C. C. Cheung, J. Kataoka, S. Funk, T. Yuasa, H. Odaka, T. Takahashi, J. Svoboda

    Astronomy and Astrophysics   550  2013

     View Summary

    Centaurus B is a nearby radio galaxy positioned in the southern hemisphere close to the Galactic plane. Here we present a detailed analysis of about 43 months of accumulated Fermi-LAT data of the γ-ray counterpart of the source initially reported in the 2nd Fermi-LAT catalog, and of newly acquired Suzaku X-ray data. We confirm its detection at GeV photon energies and analyze the extension and variability of the γ-ray source in the LAT dataset, in which it appears as a steady γ-ray emitter. The X-ray core of Centaurus B is detected as a bright source of a continuum radiation. We do not detect, however, any diffuse X-ray emission from the known radio lobes, with the provided upper limit only marginally consistent with the previously claimed ASCA flux. Two scenarios that connect the X-ray and γ-ray properties are considered. In the first one, we assume that the diffuse non-thermal X-ray emission component is not significantly below the derived Suzaku upper limit. In this case, modeling the inverse-Compton emission shows that the observed γ-ray flux of the source may in principle be produced within the lobes. This association would imply that efficient in-situ acceleration of the radiating electrons is occurring and that the lobes are dominated by the pressure from the relativistic particles. In the second scenario, with the diffuse X-ray emission well below the Suzaku upper limits, the lobes in the system are instead dominated by the magnetic pressure. In this case, the observed γ-ray flux is not likely to be produced within the lobes, but instead within the nuclear parts of the jet. By means of synchrotron self-Compton modeling, we show that this possibility could be consistent with the broad-band data collected for the unresolved core of Centaurus B, including the newly derived Suzaku spectrum. © ESO, 2013.

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  • Geometry dependence of the light collection efficiency of BGO crystal scintillators read out by avalanche photo diodes

    M. Sasano, H. Nishioka, S. Okuyama, K. Nakazawa, K. Makishima, S. Yamada, T. Yuasa, A. Okumura, J. Kataoka, Y. Fukazawa, Y. Hanabata, K. Hayashi

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   715   105 - 111  2013

     View Summary

    Abstract Light collection efficiency from BGO crystal scintillators of various sizes and shapes was measured by reading them using 1×1 cm 2 avalanche photo diodes. When the crystals have simple geometry, the light collection efficiency was found to depend on their size, shape and the read-out position through a rather well-defined empirical scaling relation. The light collection efficiency of tapered crystals was seen to depend on both the position of γ-ray irradiation, and the read-out position of the avalanche photo diodes. Using optical Monte-Carlo simulations, the relation was reproduced assuming plausible proper parameters for surface conditions and the attenuation length. This results were reproduced with a reasonable accuracy by optical Monte-Carlo simulations. Simple physical explanations are given to these geometrical effects. © 2013 Elsevier B.V.

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  • Development of signal processing system of avalanche photo diode for space observations by Astro-H

    Ohno M, Goto K, Hanabata Y, Takahashi H, Fukazawa Y, Yoshino M, Saito T, Nakamori T, Kataoka J, Sasano M, Torii S, Uchiyama H, Nakazawa K, Watanabe S, Kokubun M, Ohta M, Sato T, Takahashi T, Tajima H

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   699   112 - 115  2013  [Refereed]

     View Summary

    Astro-H is the sixth Japanese X-ray space observatory which will be launched in 2014. Two of onboard instruments of Astro-H, Hard X-ray Imager and Soft Gamma-ray Detector are surrounded by many number of large Bismuth Germanate (Bi4Ge3O12; BGO) scintillators. Optimum readout system of scintillation lights from these BGOs are essential to reduce the background signals and achieve high performance for main detectors because most of gamma-rays from out of field-of-view of main detectors or radio-isotopes produced inside them due to activation can be eliminated by anti-coincidence technique using BGO signals. We apply Avalanche Photo Diode (APD) for light sensor of these BGO detectors since their compactness and high quantum efficiency make it easy to design such large number of BGO detector system. For signal processing from APDs, digital filter and other trigger logics on the Field-Programmable Gate Array (FPGA) is used instead of discrete analog circuits due to limitation of circuit implementation area on spacecraft. For efficient observations, we have to achieve as low threshold of anti-coincidence signal as possible by utilizing the digital filtering. In addition, such anti-coincident signals should be sent to the main detector within 5μs to make it in time to veto the A-D conversion. Considering this requirement and constraint from logic size of FPGA, we adopt two types of filter, 8 delay taps filter with only 2 bit precision coefficient and 16 delay taps filter with 8 bit precision coefficient. The data after former simple filter provides anti-coincidence signal quickly in orbit, and the latter filter is used for detail analysis after the data is down-linked. © 2012 Elsevier B.V.

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  • A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

    T. Kato, J. Kataoka, T. Nakamori, T. Miura, H. Matsuda, A. Kishimoto, K. Sato, Y. Ishikawa, K. Yamamura, S. Nakamura, N. Kawabata, H. Ikeda, S. Yamamoto, K. Kamada

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   699   235 - 241  2013.01  [Refereed]

     View Summary

    We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4 x 4 channels with a three-side buttable package. Each channel has a photosensitive area of 3 x 3 mm(2) and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5 x 10(5) at +20 degrees C, gain fluctuation over the entire MPPC device is only +/- 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to &lt;= 400 kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu, Y)(2)(SiO4)O (Ce:LYSO) crystal array (4 x 4 array of 3 x 3 x 10 mm(3) crystals). Energy and time resolutions of 11.5 +/- 0.5% (FWHM at 662 keV) and 493 +/- 22 ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2 +/- 0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd3Ga3Al2O12 (Ce:GGAG) scintillator matrices each consisting of 1.0 x 1.0, 0.7 x 0.7 and 0.5 x 0.5 mm(2) pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a Cs-137 source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were &lt;= 14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET). (C) 2012 Elsevier B.V. All rights reserved.

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  • Development of high performance Avalanche Photodiodes and dedicated analog systems for HXI/SGD detectors onboard the Astro-H mission

    T. Saito, T. Nakamori, M. Yoshino, H. Mizoma, J. Kataoka, K. Kawakami, Y. Yatsu, M. Ohno, K. Goto, Y. Hanabata, H. Takahashi, Y. Fukazawa, M. Sasano, S. Torii, H. Uchiyama, K. Nakazawa, K. Makishima, S. Watanabe, M. Kokubun, T. Takahashi, K. Mori, H. Tajima

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   699   230 - 234  2013.01  [Refereed]

     View Summary

    Hard X-ray Imager and Soft Gamma-ray Detector are being developed as onboard instruments for the Astro-H mission, which is scheduled for launch in 2014. In both detectors, EGO scintillators play key roles in achieving high sensitivity in low Earth orbit (LEO), by generating active veto signals to reject cosmic-ray events and gamma-ray backgrounds from radio-activated detector materials. In order to maximize background rejection power, it is also important to minimize the energy threshold of this shield. As a readout sensor of weak scintillation light from a number of EGO crystals in a complicated detector system, high performance, reverse-type Avalanche Photodiodes (APDs), with an effective area of 10 x 10 mm(2) are being employed, instead of bulky photomultiplier tubes (PMTs). Another advantage of using APDs is their low power consumption, although the relatively low gain of APDs (compared to conventional PMTs) requires dedicated analog circuits for noise suppression. In this paper, we report on the development and performance of APD detectors specifically designed for the Astro-H mission. In addition to APD performance, various environmental tests, including radiation hardness and qualification thermal cycling, will be described in detail. Moreover, a dedicated charge sensitive amplifier and analog filters are newly developed and tested here to optimize the performance of APDs to activate fast veto signals within a few is from the EGO trigger. We will also report on overall performance testing of a prototype EGO detector system that mimics the data acquisition system onboard Astro-H. (C) 2012 Elsevier B.V. All rights reserved.

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  • Development of a dual-sided readout DOI-PET module using large-area monolithic mppc-arrays

    Aya Kishimoto, Jun Kataoka, Takuya Kato, Takamasa Miura, Takeshi Nakamori, Kei Kamada, Shigeyuki Nakamura, Kenichi Sato, Yoshitaka Ishikawa, Kazuhisa Yamamura, Nobuyuki Kawabata, Seiichi Yamamoto

    IEEE Transactions on Nuclear Science   60 ( 1 ) 38 - 43  2013

     View Summary

    We are proposing a novel design for a module with depth of interaction (DOI) capability for gamma rays by measuring the pulse-height ratio of double-sided Multi-Pixel Photon Counters (MPPCs) coupled at both ends of a scintillation crystal block. Thanks to newly developed monolithic MPPC arrays consisting of 4 × 4 channels with a three-side buttable package, the module is very thin and compact, thereby enabling less dead space between each module when arranged into a fully designed gantry. To demonstrate our concept of a DOI measuring technique, we first made a 1-D crystal array consisting of five Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) cubic crystals measuring 3× 3× 3\\mm3 in size, separated by a layer of air approximately 10 μ m-thick. When the light signals output from both ends are read with the 3× 3 mm2 MPPCs, the position of each crystal is clearly distinguished. The same measurements were also made using Ce-doped (Lu,Y)2(SiO4)O(Ce:LYSO), achieving a similarly good separation. We then fabricated thin Ce:GAGG 2-D crystal arrays consisting of two types: [A] 4 × 4 matrix of 3× 3× 3mm} 3 pixels, and [B] 10 × 10 matrix of 0.8× 0.8× 5 mm3 pixels, with each pixel divided by a BaSO4 reflector 0.2 mm-thick. Then four arrays are laid on top of each other facing the DOI direction through a layer of air 10 μm-thick. We demonstrated that the 3-D position of each Ce:GAGG pixel is clearly distinguished in both the 2-D and DOI directions for type A and B when illuminated by 662 keV gamma rays. Average energy resolutions of 9.8 ± 0.8% and 11.8 ± 1.3% were obtained for types A and B, respectively. These results suggest that our proposed method is simple and offers promise in achieving both excellent spatial and energy resolutions for future medical imaging, particularly in positron emission tomography (PET). © 1963-2012 IEEE.

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  • Binary millisecond pulsar discovery via gamma-ray pulsations

    H.J. Pletsch, L. Guillemot, H. Fehrmann, B. Allen, M. Kramer, C. Aulbert, M. Ackermann, M. Ajello, A. De Angelis, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, R.C.G. Chaves, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, C.D. Dermer, S.W. Digel, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Favuzzi, E.C. Ferrara, A. Franckowiak, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, P.R. Den Hartog, M. Hayashida, E. Hays, A.B. Hill, X. Hou, R.E. Hughes, G. Jóhannesson, M.S. Jackson, T. Jogler, A.S. Johnson, W.N. Johnson, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, F. Massaro, M. Mayer, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, R. Nemmen, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, F. De Palma, D. Paneque, J.S. Perkins, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, R.W. Romani, C. Romoli, D.A. Sanchez, P.M. Saz Parkinson, A. Schulz, C. Sgrò, E. Do Couto E Silva, E.J. Siskind, D.A. Smith, G. Spandre, P. Spinelli, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, S. Zimmer

    Science   338 ( 6112 ) 1314 - 1317  2012.12  [Refereed]

     View Summary

    Millisecond pulsars, old neutron stars spun up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such "recycled"rotation-powered pulsars have been detected by their spin-modulated radio emission. In a computing-intensive blind search of gamma-ray data from the Fermi Large Area Telescope (with partial constraints from optical data), we detected a 2.5-millisecond pulsar, PSR J1311-3430. This unambiguously explains a formerly unidentified gamma-ray source that had been a decade-long enigma, confirming previous conjectures. The pulsar is in a circular orbit with an orbital period of only 93 minutes, the shortest of any spin-powered pulsar binary ever found.

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  • The imprint of the extragalactic background light in the gamma-ray spectra of blazars

    M. Ackermann, M. Ajello, A. Allafort, P. Schady, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, R.D. Blandford, E.D. Bloom, A.W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, R.C.G. Chaves, A. Chekhtman, C.C. Cheung, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, A. Domínguez, P.S. Drell, A. Drlica-Wagner, C. Favuzzi, S.J. Fegan, W.B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, M.S. Jackson, T. Jogler, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, A. Tramacere, E. Nuss, J. Greiner, M. Ohno, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, D. Paneque, J.S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L.C. Reyes, S. Ritz, A. Rau, C. Romoli, M. Roth, M. Sánchez-Conde, D.A. Sanchez, J.D. Scargle, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, Ł. Stawarz, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, M. Wood

    Science   338 ( 6111 ) 1190 - 1192  2012.11  [Refereed]

     View Summary

    The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z ∼ 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.

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  • The fermi large area telescope on orbit: Event classification, instrument response functions, and calibration

    M. Ackermann, M. Ajello, A. Albert, A. Allafort, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, J. R. Bogart, E. Bonamente, A. W. Borgland, E. Bottacini, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, E. Charles, R. C.G. Chaves, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, R. Corbet, S. Cutini, F. D'Ammando, D. S. Davis, A. De Angelis, M. Deklotz, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, X. Hou, R. E. Hughes, M. S. Jackson, T. Jogler, G. Jóhannesson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, C. Lavalley, M. Lemoine-Goumard, F. Longo

    Astrophysical Journal, Supplement Series   203 ( 1 )  2012.11

     View Summary

    The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy γ-ray telescope, covering the energy range from 20MeV to more than 300GeV. During the first years of the mission, the LAT team has gained considerable insight into the in-flight performance of the instrument. Accordingly, we have updated the analysis used to reduce LAT data for public release as well as the instrument response functions (IRFs), the description of the instrument performance provided for data analysis. In this paper, we describe the effects that motivated these updates. Furthermore, we discuss how we originally derived IRFs from Monte Carlo simulations and later corrected those IRFs for discrepancies observed between flight and simulated data. We also give details of the validations performed using flight data and quantify the residual uncertainties in the IRFs. Finally, we describe techniques the LAT team has developed to propagate those uncertainties into estimates of the systematic errors on common measurements such as fluxes and spectra of astrophysical sources. © 2012 The American Astronomical Society. All rights reserved.

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  • Development of a MPPC-based DOI-PET module with submillimeter 3-D resolution

    Kishimoto, A, Kataoka, J, Kato, T, Miura, T, Nakamori, T, Kamada, K, Nakamura, S, Sato, K, Ishikawa, Y, Ymamura, K, Yamamoto, S

    2012 IEEE NSS/MIC Conference Record     3128 - 3133  2012.10

     View Summary

    We are proposing a novel design for a module with depth of interaction (DOI) capability for gamma rays by measuring the pulse-height ratio of double-sided Multi-Pixel Photon Counters (MPPCs) coupled at both ends of a scintillation crystal block. Thanks to newly developed monolithic MPPC arrays consisting of 4×4 channels with a three-side buttable package, the module is very thin and compact, thereby enabling less dead space between each module when arranged into a fully designed gantry. To demonstrate our concept of a DOI measuring technique, we first made a 1-D crystal array consisting of five Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) cubic crystals measuring 3×3×3 mm3 in size, separated by a layer of air. When the light signals output from both ends are read with the MPPCs, the position of each crystal is clearly distinguished with a spatial uncertainty of 0.48±0.03 mm. For 3-D measurements, we then fabricated three different type arrays: [A] 4×4×4 matrix of 3×3×3 mm3 pixels, [B] 5×5×5 matrix of 2×2×2 mm 3 pixels, and [C] 10×10×10 matrix of 1×1×1 mm3 pixels, with each pixel divided by a BaSO4 reflector in the 2-D direction and by a layer of air in the DOI direction. We demonstrated that the 3-D position of each Ce:GAGG pixel was clearly distinguished when illuminated by 662 keV gamma rays uniformly. Average energy resolutions of 9.8±0.8 %, 9.8±0.9 %, and 13.2±1.7 % were obtained for types A, B and C, respectively. These results suggest that our proposed method is simple and offers promise in achieving 1 mm 3-D spatial resolution for future medical imaging, particularly in positron emission tomography (PET). © 2012 IEEE.

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  • High position resolution gamma-ray imagers consisting of a monolithic MPPC array with submillimeter pixelized scintillator crystals

    Kato, T, Kataoka, J, Nakamori, T, Kishimoto, A, Yamamoto, S, Sato, K, Ishikawa, Y, Yamamura, K, Nakamura, S, Kawabata, N, Ikeda, H, Kamada, K

    2012 IEEE NSS/MIC Conference Record     3146 - 3152  2012.10

     View Summary

    We report on the development of two versatile, high spatial resolution gamma-ray imagers for medical imaging. One is a compact gamma-ray camera, the other is a tweezers type coincidence imaging system. These applications consisting of a large-area monolithic Multi-Pixel Photon Counter (MPPC) and submillimeter pixelized scintillator matrices. The MPPC array has 4×4 channels with a three-side buttable, very compact package. Each channel has a photosensitive area of 3×3 mm2 and 3600 Geiger mode avalanche photodiodes (APD). For a typical operational gain of 7.5×105 at + 20 degrees, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400 kcps per channel. We particularly selected Ce-doped (Lu,Y) 2(SiO4)O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated to 22×22 or 15×15 matrices of 0.5×0.5 mm2 pixels. These scintillator matrices were coupled to the MPPC array with an acrylic light guide with 1 mm thick, and signals were read out using the charge division resistor network, which compiles signals into four position-encoded analog outputs. The spatial resolution of 1.2 mm was achieved with the compact gamma-ray camera using collimated 57Co source, and a radiography image of a bearing was successfully obtained. On the other hand, the spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22Na source. Furthermore the experimental measurements for a PET scanner was performed, and the spatial resolution of 0.91 mm was achieved. These results suggest that the gamma-ray imagers has excellent potential for their uses as a high spatial medical imaging, and also be promising for positron emission tomography (PET). © 2012 IEEE.

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  • Fermi observations of γ-ray emission from the moon

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwoo, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E. Bonamente, A.W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, G.A. Gomez-Vargas, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, E. Hays, A.B. Hill, D. Horan, X. Hou, R.E. Hughes, G. Iafrate, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, H. Poon, T.A. Porter, D. Prokhorov, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, M. Roth, H.F.-W. Sadrozinski, D.A. Sanchez, C. Sbarra, T.L. Schalk, C. Sgrò, G.H. Share, E.J. Siskind, G. Spandre, P. Spinelli, Ł. Stawarz, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, D.L. Wood, K.S. Wood, Z. Yang, S. Zimmer

    Astrophysical Journal   758 ( 2 )  2012.10  [Refereed]

     View Summary

    We report on the detection of high-energy γ-ray emission from the Moon during the first 24 months of observations by the Fermi Large Area Telescope (LAT). This emission comes from particle cascades produced by cosmic-ray (CR) nuclei and electrons interacting with the lunar surface. The differential spectrum of the Moon is soft and can be described as a log-parabolic function with an effective cutoff at 2-3GeV, while the average integral flux measured with the LAT from the beginning of observations in 2008 August to the end of 2010 August is F(>cm-2s-1. This flux is about a factor 2-3 higher than that observed between 1991 and 1994 by the EGRET experiment on board the Compton Gamma Ray Observatory, F(>100 MeV) ≈ 5 × 10-7cm-2s-1, when solar activity was relatively high. The higher γ-ray flux measured by Fermi is consistent with the deep solar minimum conditions during the first 24 months of the mission, which reduced effects of heliospheric modulation, and thus increased the heliospheric flux of Galactic CRs. A detailed comparison of the light curve with McMurdo Neutron Monitor rates suggests a correlation of the trends. The Moon and the Sun are so far the only known bright emitters of γ-rays with fast celestial motion. Their paths across the sky are projected onto the Galactic center and high Galactic latitudes as well as onto other areas crowded with high-energy γ-ray sources. Analysis of the lunar and solar emission may thus be important for studies of weak and transient sources near the ecliptic. © 2012. The American Astronomical Society. All rights reserved.

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  • TOWARD IDENTIFYING THE UNASSOCIATED GAMMA-RAY SOURCE 1FGL J1311.7-3429 WITH X-RAY AND OPTICAL OBSERVATIONS

    J. Kataoka, Y. Yatsu, N. Kawai, Y. Urata, C. C. Cheung, Y. Takahashi, K. Maeda, T. Totani, R. Makiya, H. Hanayama, T. Miyaji, A. Tsai

    ASTROPHYSICAL JOURNAL   757 ( 2 ) 176 - 184  2012.10  [Refereed]

     View Summary

    We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoidal optical modulation of Delta m similar to 2 mag with a period of similar or equal to 1.5 hr in the Rc, r', and g' bands. Moreover, we found that the amplitude of the modulation and peak intensity changed by greater than or similar to 1 mag and similar to 0.5 mag, respectively, over our total six nights of observations from 2012 March to May. Combined with Swift UVOT data, the optical-UV spectrum is consistent with a blackbody temperature, kT similar or equal to 1 eV and the emission volume radius R-bb similar or equal to 1.5 x 10(4) d(kpc) km (d(kpc) is the distance to the source in units of 1 kpc). In contrast, deep Suzaku observations conducted in 2009 and 2011 revealed strong X-ray flares with a light curve characterized with a power spectrum density of P(f) proportional to f(-2.0 +/- 0.4), but the folded X-ray light curves suggest an orbital modulation also in X-rays. Together with the non-detection of a radio counterpart, and significant curved spectrum and non-detection of variability in gamma-rays, the source may be the second "radio-quiet" gamma-ray emitting millisecond pulsar candidate after 1FGL J2339.7-0531, although the origin of flaring X-ray and optical variability remains an open question.

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  • TOWARD IDENTIFYING THE UNASSOCIATED GAMMA-RAY SOURCE 1FGL J1311.7-3429 WITH X-RAY AND OPTICAL OBSERVATIONS

    J. Kataoka, Y. Yatsu, N. Kawai, Y. Urata, C. C. Cheung, Y. Takahashi, K. Maeda, T. Totani, R. Makiya, H. Hanayama, T. Miyaji, A. Tsai

    ASTROPHYSICAL JOURNAL   757 ( 2 )  2012.10

     View Summary

    We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoidal optical modulation of Delta m similar to 2 mag with a period of similar or equal to 1.5 hr in the Rc, r', and g' bands. Moreover, we found that the amplitude of the modulation and peak intensity changed by greater than or similar to 1 mag and similar to 0.5 mag, respectively, over our total six nights of observations from 2012 March to May. Combined with Swift UVOT data, the optical-UV spectrum is consistent with a blackbody temperature, kT similar or equal to 1 eV and the emission volume radius R-bb similar or equal to 1.5 x 10(4) d(kpc) km (d(kpc) is the distance to the source in units of 1 kpc). In contrast, deep Suzaku observations conducted in 2009 and 2011 revealed strong X-ray flares with a light curve characterized with a power spectrum density of P(f) proportional to f(-2.0 +/- 0.4), but the folded X-ray light curves suggest an orbital modulation also in X-rays. Together with the non-detection of a radio counterpart, and significant curved spectrum and non-detection of variability in gamma-rays, the source may be the second "radio-quiet" gamma-ray emitting millisecond pulsar candidate after 1FGL J2339.7-0531, although the origin of flaring X-ray and optical variability remains an open question.

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  • Gamma-ray observations of the orion molecular clouds with the fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, C. Cecchi, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. D'Ammando, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, T. Enoto, L. Falletti, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, Y. Fukazawa, Y. Fukui, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, K. Hayashi, D. Horan, X. Hou, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, S.-H. Lee, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, K. Makishima, M.N. Mazziotta, J. Mehault, W. Mitthumsiri, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, S. Nishino, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, M. Orienti, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, M. Razzano, A. Reimer, O. Reimer, M. Roth, H.F.-W. Sadrozinski, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, A.W. Strong, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, O. Tibolla, M. Tinivella, D.F. Torres, A. Tramacere, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, S. Zimmer

    Astrophysical Journal   756 ( 1 )  2012.09  [Refereed]

     View Summary

    We report on the gamma-ray observations of giant molecular clouds Orion A and B with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The gamma-ray emission in the energy band between 100MeV and 100GeV is predicted to trace the gas mass distribution in the clouds through nuclear interactions between the Galactic cosmic rays (CRs) and interstellar gas. The gamma-ray production cross-section for the nuclear interaction is known to 10% precision which makes the LAT a powerful tool to measure the gas mass column density distribution of molecular clouds for a known CR intensity. We present here such distributions for Orion A and B, and correlate them with those of the velocity-integrated CO intensity (W CO) at a 1° × 1°pixel level. The correlation is found to be linear over a W CO range of ∼10-fold when divided in three regions, suggesting penetration of nuclear CRs to most of the cloud volumes. The W CO-to-mass conversion factor, X CO, is found to be ∼2.3 × 1020 cm-2(K km s-1)-1 for the high-longitude part of Orion A (l > ∼212°), 1.7times higher than ∼1.3 × 10 20 found for the rest of Orion A and B. We interpret the apparent high X CO in the high-longitude region of Orion A in the light of recent works proposing a nonlinear relation between H2 and CO densities in the diffuse molecular gas. W CO decreases faster than the H2 column density in the region making the gas "darker" to W CO. © © 2012. The American Astronomical Society. All rights reserved..

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  • Development of a micro-satellite TSUBAME for X-ray polarimetry of GRBs

    Yatsu, Y, Hayashi, M, Kawakami, K, Tokoyoda, K, Enomoto, T, Toizumi, T, Kawai, N, Ishizaka, K, Muta, A, Morishita, H, Matsunaga, S, Nakamori, T, Kataoka, J, Kubo, S

    Proceedings of the International Astronomical Union   279 ( S279 ) 423 - 424  2012.09

     View Summary

    Hard X-ray polarization is believed to be one of the most promising methods to investigate the physical processes just around the central engines by constraining the magnetic environment. For this purpose we are now developing a compact and highly sensitive hard X-ray polarimeter aboard a university class micro-satellite TSUBAME. We are now developing the flight model of the satellite aiming for the launch in late 2012 from Russia. © 2012 International Astronomical Union.

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  • GeV observations of star-forming galaxies with the fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, C. Favuzzi, S.J. Fegan, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, P. Martin, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, S. Nishino, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, M. Ozaki, D. Parent, M. Persic, M. Pesce-Rollins, V. Petrosian, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Roth, C. Sbarra, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, L. Stawarz, A.W. Strong, H. Takahashi, T. Tanaka, J.B. Thayer, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, J. Vandenbroucke, G. Vianello, V. Vitale, A.P. Waite, M. Wood, Z. Yang

    Astrophysical Journal   755 ( 2 )  2012.08  [Refereed]

     View Summary

    Recent detections of the starburst galaxies M82 and NGC253 by gamma-ray telescopes suggest that galaxies rapidly forming massive stars are more luminous at gamma-ray energies compared to their quiescent relatives. Building upon those results, we examine a sample of 69 dwarf, spiral, and luminous and ultraluminous infrared galaxies at photon energies 0.1-100 GeV using 3years of data collected by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi). Measured fluxes from significantly detected sources and flux upper limits for the remaining galaxies are used to explore the physics of cosmic rays in galaxies. We find further evidence for quasi-linear scaling relations between gamma-ray luminosity and both radio continuum luminosity and total infrared luminosity which apply both to quiescent galaxies of the Local Group and low-redshift starburst galaxies (conservative P-values ≲ 0.05 accounting for statistical and systematic uncertainties). The normalizations of these scaling relations correspond to luminosity ratios of log (L 0.1-100 GeV/L 1.4 GHz) = 1.7 ± 0.1 (statistical) ± 0.2(dispersion) and log (L 0.1-100 GeV/L 8-1000 μm) = -4.3 ± 0.1 (statistical) ± 0.2(dispersion) for a galaxy with a star formation rate of 1 M yr-1, assuming a Chabrier initial mass function. Using the relationship between infrared luminosity and gamma-ray luminosity, the collective intensity of unresolved star-forming galaxies at redshifts 0 < z < 2.5 above 0.1 GeV is estimated to be 0.4-2.4 × 10-6 ph cm-2 s-1 sr-1 (4%-23% of the intensity of the isotropic diffuse component measured with the LAT). We anticipate that 10 galaxies could be detected by their cosmic-ray-induced gamma-ray emission during a 10 year Fermi mission. © 2012. The American Astronomical Society. All rights reserved.

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  • Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, G. Busetto, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. D'Ammando, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, Y. Fukazawa, Y. Fukui, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, D. Horan, X. Hou, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, P. Martin, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, R. Nemmen, S. Nishino, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, C. Romoli, M. Roth, T. Sada, H.F.-W. Sadrozinski, D.A. Sanchez, C. Sbarra, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, A.W. Strong, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, M. Tinivella, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, H. Yamamoto, Z. Yang, S. Zimmer

    Astrophysical Journal   755 ( 1 )  2012.08  [Refereed]

     View Summary

    We report an analysis of the interstellar γ-ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within 300pc from the solar system. The γ-ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ-ray emissivities above 250MeV are (5.9 ± 0.1stat+0.9-1.0sys) × 10-27photonss-1sr-1 H-atom-1, (10.2 ± 0.4stat+1.2-1.7sys) × 10 -27photonss-1sr-1 H-atom-1, and (9.1 ± 0.3stat+1.5-0.6sys) × 10 -27photonss-1sr-1 H-atom-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250MeV to 10 GeV indicate a variation of the CR density by 20% in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, X CO = N(H2)/W CO, is found to be (0.96 ± 0.06stat+0.15-0.12sys) × 1020 H2-moleculecm-2 (Kkms -1)-1, (0.99 ± 0.08stat+0.18-0.10sys) × 1020 H2-moleculecm -2 (Kkms-1)-1, and (0.63 ± 0.02 stat+0.09-0.07sys) × 1020 H2-moleculecm-2 (Kkms-1)-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of X CO in the vicinity of the solar system. From the obtained values of X CO, the masses of molecular gas traced by W CO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be 5 × 103 M, 103 M, and 3.3 × 104 M ,respectively. A comparable amount of gas not traced well by standard H I and CO surveys is found in the regions investigated. © 2012. The American Astronomical Society. All rights reserved.

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  • Constraining the high-energy emission from gamma-ray bursts with Fermi

    M. Ackermann, M. Ajello, L. Baldini, G. Barbiellini, M.G. Baring, K. Bechtol, R. Bellazzini, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, A. Bouvier, M. Brigida, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, F. D'Ammando, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, J. Granot, I.A. Grenier, J.E. Grove, D. Hadasch, Y. Hanabata, A.K. Harding, E. Hays, D. Horan, G. Jóhannesson, J. Kataoka, J. Knödlseder, D. Kocevski, M. Kuss, J. Lande, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J. McEnery, S. McGlynn, P.F. Michelson, W. Mitthumsiri, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, J.P. Norris, E. Nuss, T. Nymark, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.H. Panetta, D. Parent, V. Pelassa, M. Pesce-Rollins, F. Piron, G. Pivato, J.L. Racusin, S. Rainò, R. Rando, S. Razzaque, A. Reimer, O. Reimer, S. Ritz, F. Ryde, C. Sgrò, E.J. Siskind, E. Sonbas, G. Spandre, P. Spinelli, M. Stamatikos, Ł. Stawarz, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, L. Tibaldo, M. Tinivella, G. Tosti, T. Uehara, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, V. Connaughton, M.S. Briggs, S. Guirec, A. Goldstein, J.M. Burgess, P.N. Bhat, E. Bissaldi, A. Camero-Arranz, J. Fishman, G. Fitzpatrick, S. Foley, D. Gruber, P. Jenke, R.M. Kippen, C. Kouveliotou, S. McBreen, C. Meegan, W.S. Paciesas, R. Preece, A. Rau, D. Tierney, A.J. Van, Der Horst, A. Von Kienlin, C. Wilson-Hodge, S. Xiong

    Astrophysical Journal   754 ( 2 )  2012.08  [Refereed]

     View Summary

    We examine 288 gamma-ray bursts (GRBs) detected by the Fermi Gamma-ray Space Telescope's Gamma-ray Burst Monitor (GBM) that fell within the field of view of Fermi's Large Area Telescope (LAT) during the first 2.5years of observations, which showed no evidence for emission above 100MeV. We report the photon flux upper limits in the 0.1-10GeV range during the prompt emission phase as well as for fixed 30s and 100s integrations starting from the trigger time for each burst. We compare these limits with the fluxes that would be expected from extrapolations of spectral fits presented in the first GBM spectral catalog and infer that roughly half of the GBM-detected bursts either require spectral breaks between the GBM and LAT energy bands or have intrinsically steeper spectra above the peak of the νF ν spectra (E pk). In order to distinguish between these two scenarios, we perform joint GBM and LAT spectral fits to the 30 brightest GBM-detected bursts and find that a majority of these bursts are indeed softer above E pk than would be inferred from fitting the GBM data alone. Approximately 20% of this spectroscopic subsample show statistically significant evidence for a cutoff in their high-energy spectra, which if assumed to be due to γγ attenuation, places limits on the maximum Lorentz factor associated with the relativistic outflow producing this emission. All of these latter bursts have maximum Lorentz factor estimates that are well below the minimum Lorentz factors calculated for LAT-detected GRBs, revealing a wide distribution in the bulk Lorentz factor of GRB outflows and indicating that LAT-detected bursts may represent the high end of this distribution. © 2012. The American Astronomical Society. All rights reserved..

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  • Large size single crystal growth of Lu3Al5O12:Pr and their uniformity of scintillation properties

    Kei Kamada, Takayuki Yanagida, Takanori Endo, Kousuke Tsutumi, Masao Yoshino, Jun Kataoka, Yoshiyuki Usuki, Yutaka Fujimoto, Akihiro Fukabori, Akira Yoshikawa

    JOURNAL OF CRYSTAL GROWTH   352 ( 1 ) 91 - 94  2012.08  [Refereed]

     View Summary

    Pr-doped Lu3Al5O12 (Pr:LuAG) single crystals were grown by the Czochralski method. The crystal was seeded-grown in the [100] direction. Dimensions up to 100 mm in length and 92 mm in diameter were achieved without cracking. Using 10 x 10 x 10 mm size sample coupled with photomultiplier (Hamamatsu R3998), energy resolution of 4.6% at 662 keV was achieved. Uniformity of light yield and energy resolution was also evaluated in whole crystal. The deviations of light output, energy resolution, and decay time were +/- 7.9%, 7.2%, and 4.8%, respectively. (C) 2011 Elsevier B.V. All rights reserved.

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  • A statistical approach to recognizing source classes for unassociated sources in the first Fermi-lat catalog

    M. Ackermann, M. Ajello, A. Allafort, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, A.W. Chen, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, M.E. Decesar, A. De Luca, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, T. Enoto, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, S.E. Healey, A.B. Hill, D. Horan, X. Hou, G. Jóhannesson, A.S. Johnson, T.J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, R.P. Mignani, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, R.W. Romani, H.F.-W. Sadrozinski, D. Salvetti, P.M.S. Parkinson, T.L. Schalk, C. Sgrò, M.S. Shaw, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, M.T. Wolff, D.L. Wood, K.S. Wood, Z. Yang, S. Zimmer

    Astrophysical Journal   753 ( 1 )  2012.07  [Refereed]

     View Summary

    The Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of γ-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of source types known to emit γ rays, 630 of these sources are "unassociated" (i.e., have no obvious counterparts at other wavelengths). Here, we employ two statistical analyses of the primary γ-ray characteristics for these unassociated sources in an effort to correlate their γ-ray properties with the active galactic nucleus (AGN) and pulsar populations in 1FGL. Based on the correlation results, we classify 221 AGN-like and 134 pulsar-like sources in the 1FGL unassociated sources. The results of these source "classifications" appear to match the expected source distributions, especially at high Galactic latitudes. While useful for planning future multiwavelength follow-up observations, these analyses use limited inputs, and their predictions should not be considered equivalent to "probable source classes" for these sources. We discuss multiwavelength results and catalog cross-correlations to date, and provide new source associations for 229 Fermi-LAT sources that had no association listed in the 1FGL catalog. By validating the source classifications against these new associations, we find that the new association matches the predicted source class in ∼80% of the sources. © 2012 The American Astronomical Society. All rights reserved.

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  • VLBI and single-dish monitoring of 3C 84 for the period 2009-2011

    H. Nagai, M. Orienti, M. Kino, K. Suzuki, G. Giovannini, A. Doi, K. Asada, M. Giroletti, J. Kataoka, F. D'Ammando, M. Inoue, A. Lähteenmäki, M. Tornikoski, J. Léon-Tavares, S. Kameno, U. Bach

    Monthly Notices of the Royal Astronomical Society: Letters   423 ( 1 )  2012.06

     View Summary

    The radio galaxy 3C 84 is a representative of γ -ray-bright misaligned active galactic nuclei (AGNs) and one of the best laboratories to study the radio properties of the subparsec jet in connection with the γ -ray emission. In order to identify possible radio counterparts of γ -ray emissions in 3C 84, we study the change in structure within the central 1 pc and the light curve of subparsec-sized components C1, C2 and C3. We search for any correlation between changes in the radio components and the γ -ray flares by making use of the Very Long Baseline Interferometry (VLBI) and single-dish data. Throughout the radio monitoring spanning over two GeV γ -ray flares detected by the Fermi Large Area Telescope and theMAGIC Cherenkov Telescope during 2009 April-May and 2010 June-August, the total flux density in the radio band increases on average. This flux increase mostly originates in C3. Although γ -ray flares span the time-scale of days to weeks, no clear correlation with the radio light curve on this time-scale is found. No new prominent components and change in morphology associated with the γ -ray flares are found on VLBI images. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society. © 2012 RAS.

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    33
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    (Scopus)
  • Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

    M. Ackermann, M. Ajello, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, F. D'Ammando, F. De Palma, C.D. Dermer, E. Do Couto E. Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, L. Fuhrmann, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, M. Ozaki, D. Paneque, J.H. Panetta, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, D. Rastawicki, M. Razzano, A. Readhead, A. Reimer, O. Reimer, L.C. Reyes, J.L. Richards, C. Sbarra, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, A. Szostek, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, Z. Yang, S. Zimmer, R. Moderski, K. Nalewajko, M. Sikora, M. Villata, C.M. Raiteri, H.D. Aller, M.F. Aller, A.A. Arkharov, E. Benítez, A. Berdyugin, D.A. Blinov, M. Boettcher, O.J.A, Bravo Calle, C.S. Buemi, D. Carosati, W.P. Chen, C. Diltz, A. Dipaola, M. Dolci, N.V. Efimova, E. Forné, M.A. Gurwell, J. Heidt, D. Hiriart, B. Jordan, G. Kimeridze, T.S. Konstantinova, E.N. Kopatskaya, E. Koptelova, O.M. Kurtanidze, A. Lähteenmäki, E.G. Larionova, L.V. Larionova, V.M. Larionov, P. Leto, E. Lindfors, H.C. Lin, D.A. Morozova, M.G. Nikolashvili, K. Nilsson, M. Oksman, P. Roustazadeh, A. Sievers, L.A. Sigua, A. Sillanpää, T. Takahashi, L.O. Takalo, M. Tornikoski, C. Trigilio, I.S. Troitsky, G. Umana, E. Angelakis, T.P. Krichbaum, I. Nestoras, D. Riquelme, M. Krips, S. Trippe, A. Arai, K.S. Kawabata, K. Sakimoto, M. Sasada, S. Sato, M. Uemura, M. Yamanaka, M. Yoshida, T. Belloni, G. Tagliaferri, E.W. Bonning, J. Isler, C.M. Urry, E. Hoversten, A. Falcone, C. Pagani, M. Stroh

    Astrophysical Journal   751 ( 2 )  2012.06  [Refereed]

     View Summary

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus. © 2012. The American Astronomical Society. All rights reserved.

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    58
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  • Expected radiation damage of reverse-type APDs for the Astro-H mission

    J. Kataoka, T. Saito, M. Yoshino, H. Mizoma, T. Nakamori, Y. Yatsu, Y. Ishikawa, Y. Matsunaga, H. Tajima, M. Kokubun, P. G. Edwards

    JOURNAL OF INSTRUMENTATION   7 ( 6 )  2012.06  [Refereed]

     View Summary

    Scheduled for launch in 2014, Astro-H is the sixth Japanese X-ray astronomy satellite mission. More than 60 silicon avalanche photodiodes (Si-APDs; hereafter APDs) will be used to read out BGO scintillators, which are implemented to generate a veto signal to reduce background contamination for the hard X-ray imager (HXI) and a soft gamma-ray detector (SGD). To date, however, APDs have rarely been used in space experiments. Moreover, strict environmental tests are necessary to guarantee APD performance for missions expected to extend beyond five years. The radiation hardness of APDs, as for most semiconductors, is particularly crucial, since radiation in the space environment is severe. In this paper, we present the results of radiation tests conducted on reverse-type APDs (provided by Hamamatsu Photonics) irradiated by gamma rays (Co-60) and 150 MeV protons. We show that, even under the same 100 Gy dose, high energy protons can cause displacement (bulk) damage in the depletion region and possibly change the activation energy, whereas gamma-ray irradiation is less prone to cause damage, because ionization damage dominates only the surface region. We also present quantitative guidance on how to estimate APD noise deterioration over a range of temperatures and radiation doses. As a practical example, we discuss the expected degradation of the BGO energy threshold for the generation of veto signals, following several years of Astro-H operation in Low Earth Orbit (LEO), and directly compare it to experimental results obtained using a small BGO crystal.

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    Scopus

    9
    Citation
    (Scopus)
  • Expected radiation damage of reverse-type APDs for the Astro-H mission

    J. Kataoka, T. Saito, M. Yoshino, H. Mizoma, T. Nakamori, Y. Yatsu, Y. Ishikawa, Y. Matsunaga, H. Tajima, M. Kokubun, P. G. Edwards

    JOURNAL OF INSTRUMENTATION   7 ( 6 )  2012.06  [Refereed]

     View Summary

    Scheduled for launch in 2014, Astro-H is the sixth Japanese X-ray astronomy satellite mission. More than 60 silicon avalanche photodiodes (Si-APDs; hereafter APDs) will be used to read out BGO scintillators, which are implemented to generate a veto signal to reduce background contamination for the hard X-ray imager (HXI) and a soft gamma-ray detector (SGD). To date, however, APDs have rarely been used in space experiments. Moreover, strict environmental tests are necessary to guarantee APD performance for missions expected to extend beyond five years. The radiation hardness of APDs, as for most semiconductors, is particularly crucial, since radiation in the space environment is severe. In this paper, we present the results of radiation tests conducted on reverse-type APDs (provided by Hamamatsu Photonics) irradiated by gamma rays (Co-60) and 150 MeV protons. We show that, even under the same 100 Gy dose, high energy protons can cause displacement (bulk) damage in the depletion region and possibly change the activation energy, whereas gamma-ray irradiation is less prone to cause damage, because ionization damage dominates only the surface region. We also present quantitative guidance on how to estimate APD noise deterioration over a range of temperatures and radiation doses. As a practical example, we discuss the expected degradation of the BGO energy threshold for the generation of veto signals, following several years of Astro-H operation in Low Earth Orbit (LEO), and directly compare it to experimental results obtained using a small BGO crystal.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Discovery of the millisecond pulsar PSR J2043+1711 in a Fermi source with the Nançay Radio Telescope

    L. Guillemot, P. C.C. Freire, I. Cognard, T. J. Johnson, Y. Takahashi, J. Kataoka, G. Desvignes, F. Camilo, E. C. Ferrara, A. K. Harding, G. H. Janssen, M. Keith, M. Kerr, M. Kramer, D. Parent, S. M. Ransom, P. S. Ray, P. M. Saz Parkinson, D. A. Smith, B. W. Stappers, G. Theureau

    Monthly Notices of the Royal Astronomical Society   422 ( 2 ) 1294 - 1305  2012.05

     View Summary

    We report the discovery of the millisecond pulsar PSR J2043+1711 in a search of a Fermi Large Area Telescope (LAT) source with no known associations, with the Nançay Radio Telescope. The new pulsar, confirmed with the Green Bank Telescope, has a spin period of 2.38ms, is relatively nearby (kpc) and is in a 1.48-d orbit around a low-mass companion, probably an He-type white dwarf. Using an ephemeris based on Arecibo, Nançay and Westerbork timing measurements, pulsed gamma-ray emission was detected in the data recorded by the Fermi LAT. The gamma-ray light curve and spectral properties are typical of other gamma-ray millisecond pulsars seen with Fermi. X-ray observations of the pulsar with Suzaku and the Swift X-ray Telescope yielded no detection. At 1.4GHz, we observe strong flux density variations because of interstellar diffractive scintillation; however, a sharp peak can be observed at this frequency during bright scintillation states. At 327MHz, the pulsar is detected with a much higher signal-to-noise ratio and its flux density is far more steady. However, at that frequency the Arecibo instrumentation cannot yet fully resolve the pulse profile. Despite that, our pulse time-of-arrival measurements have a post-fit residual rms of 2s. This and the expected stability of this system have made PSR J2043+1711 one of the first new Fermi-selected millisecond pulsars to be added to pulsar gravitational wave timing arrays. It has also allowed a significant measurement of relativistic delays in the times of arrival of the pulses due to the curvature of space-time near the companion, but not yet with enough precision to derive useful masses for the pulsar and the companion. Nevertheless, a mass for the pulsar between 1.7 and 2.0M ⊙ can be derived if a standard millisecond pulsar formation model is assumed. In this paper, we also present a comprehensive summary of pulsar searches in Fermi LAT sources with the Nançay Radio Telescope to date. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

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    43
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  • Fermi-LAT observations of the diffuse γ-ray emission: Implications for cosmic rays and the interstellar medium

    M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, X. Hou, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, H.F.-W. Sadrozinski, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, A.W. Strong, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, M. Ziegler, S. Zimmer

    Astrophysical Journal   750 ( 1 )  2012.05  [Refereed]

     View Summary

    The γ-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with the interstellar gas and radiation fields of the Milky Way. Observations of these diffuse emissions provide a tool to study cosmic-ray origin and propagation, and the interstellar medium. We present measurements from the first 21 months of the Fermi Large Area Telescope (Fermi-LAT) mission and compare with models of the diffuse γ-ray emission generated using the GALPROP code. The models are fitted to cosmic-ray data and incorporate astrophysical input for the distribution of cosmic-ray sources, interstellar gas, and radiation fields. To assess uncertainties associated with the astrophysical input, a grid of models is created by varying within observational limits the distribution of cosmic-ray sources, the size of the cosmic-ray confinement volume (halo), and the distribution of interstellar gas. An all-sky maximum-likelihood fit is used to determine the X CO factor, the ratio between integrated CO-line intensity and H2 column density, the fluxes and spectra of the γ-ray point sources from the first Fermi-LAT catalog, and the intensity and spectrum of the isotropic background including residual cosmic rays that were misclassified as γ-rays, all of which have some dependency on the assumed diffuse emission model. The models are compared on the basis of their maximum-likelihood ratios as well as spectra, longitude, and latitude profiles. We also provide residual maps for the data following subtraction of the diffuse emission models. The models are consistent with the data at high and intermediate latitudes but underpredict the data in the inner Galaxy for energies above a few GeV. Possible explanations for this discrepancy are discussed, including the contribution by undetected point-source populations and spectral variations of cosmic rays throughout the Galaxy. In the outer Galaxy, we find that the data prefer models with a flatter distribution of cosmic-ray sources, a larger cosmic-ray halo, or greater gas density than is usually assumed. Our results in the outer Galaxy are consistent with other Fermi-LAT studies of this region that used different analysis methods than employed in this paper. © 2012. The American Astronomical Society. All rights reserved.

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    636
    Citation
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  • Fermi large area telescope second source catalog

    P. L. Nolan, A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, E. Antolini, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, A. Belfiore, R. Bellazzini, B. Berenji, G. F. Bignami, R. D. Blandford, E. D. Bloom, E. Bonamente, J. Bonnell, A. W. Borgland, E. Bottacini, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, R. Campana, B. Cañadas, A. Cannon, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, M. Ceccanti, C. Cecchi, Ö Çelik, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, R. Chipaux, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, S. Cutini, F. D'Ammando, D. S. Davis, A. De Angelis, M. E. Decesar, M. Deklotz, A. De Luca, P. R. Den Hartog, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, T. Enoto, L. Escande, D. Fabiani, L. Falletti, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch

    Astrophysical Journal, Supplement Series   199 ( 2 )  2012.04

     View Summary

    We present the second catalog of high-energy γ-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100MeV to 100GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely γ-ray-producing source classes. © 2012 The American Astronomical Society. All rights reserved.

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    1211
    Citation
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  • SUZAKU X-RAY IMAGING OF THE EXTENDED LOBE IN THE GIANT RADIO GALAXY NGC 6251 ASSOCIATED WITH THE FERMI-LAT SOURCE 2FGL J1629.4+8236

    Y. Takeuchi, J. Kataoka, L. Stawarz, Y. Takahashi, K. Maeda, T. Nakamori, C. C. Cheung, A. Celotti, Y. Tanaka, T. Takahashi

    ASTROPHYSICAL JOURNAL   749 ( 1 ) 66  2012.04  [Refereed]

     View Summary

    We report the results of a Suzaku X-ray imaging study of NGC 6251, a nearby giant radio galaxy with intermediate FR I/II radio properties. Our pointing direction was centered on the gamma-ray emission peak recently discovered with the Fermi Large Area Telescope (LAT) around the position of the northwest (NW) radio lobe 15 arcmin offset from the nucleus. After subtracting two "off-source" pointings adjacent to the radio lobe and removing possible contaminants in the X-ray Imaging Spectrometer field of view, we found significant residual X-ray emission most likely diffuse in nature. The spectrum of the excess X-ray emission is well fitted by a power law with a photon index Gamma = 1.90 +/- 0.15 and a 0.5-8 keV flux of 4x10(-13) erg cm(-2) s(-1). We interpret this diffuse X-ray emission component as being due to inverse Compton upscattering of the cosmic microwave background photons by ultrarelativistic electrons within the lobe, with only a minor contribution from the beamed emission of the large-scale jet. Utilizing archival radio data for the source, we demonstrate by means of broadband spectral modeling that the gamma-ray flux of the Fermi-LAT source 2FGL J1629.4+8236 may well be accounted for by the high-energy tail of the inverse Compton continuum of the lobe. Thus, this claimed association of gamma-rays from the NW lobe of NGC 6251, together with the recent Fermi-LAT imaging of the extended lobes of Centaurus A, indicates that particles may be efficiently (re-)accelerated up to ultrarelativistic energies within extended radio lobes of nearby radio galaxies in general.

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    21
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  • Development of X-ray/gamma-ray imaging spectrometers using reach-through APD arrays

    Nakamori, T, Enomoto, T, Toizumi, T, Tokoyoda, K, Yatsu, Y, Kawai, N, Kataoka, J, Ishikawa, Y, Kawai, T, Kawabata, N, Matsunaga, Y

    Journal of Instrumentaion   7 ( 3 ) C03038 - 10pp  2012.03  [Refereed]

     View Summary

    We present spectroscopic capability of a position sensitive detector using a large area reach-through avalanche photodiode (APD) array, mainly for astronomical applications. It is quite important to obtain wide band spectra of high energy astrophysical phenomena simultaneously in order to probe emission processes or structures. Especially observations of transient objects, such as gamma-ray bursts of active galactic nuclei, require detectors with wide energy band coverage for the sake of an efficient spectroscopy within limited time windows. An APD is a compact semiconductor photon sensor with an internal gain which is often up to ∼ 100. A reach-through type APD has a thicker depletion layer thus higher efficiency for direct X-ray detection compared to a reverse type APD. We have developed 1-dimensional reach-through APD arrays which consist of 8 and 16 segments with a pixel size of 2.2 × 16 and 1.1 × 16 mm2. We demonstrated quite uniform gain and energy resolution for 5.9 keV X-ray over the pixels of these arrays. Subsequently we constructed X-ray/gamma-ray detector using the APD array optically coupled to a conventional CsI(Tl) scintillator which demonstrated energy coverage typically from 1 keV to 1 MeV. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

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    1
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  • Search for gamma-ray emission from X-ray-selected Seyfert galaxies with Fermi-lat

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, T. Enoto, C. Favuzzi, S.J. Fegan, E.C. Ferrara, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, G. Godfrey, J.E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, S. Nishino, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, E. Orlando, M. Ozaki, D. Paneque, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Roth, D.A. Sanchez, C. Sbarra, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, Ł. Stawarz, A.W. Strong, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, S. Zimmer

    Astrophysical Journal   747 ( 2 )  2012.03  [Refereed]

     View Summary

    We report on a systematic investigation of the γ-ray properties of 120 hard X-ray-selected Seyfert galaxies classified as "radio-quiet" objects, utilizing the three-year accumulation of Fermi Large Area Telescope (LAT) data. Our sample of Seyfert galaxies is selected using the Swift Burst Alert Telescope 58 month catalog, restricting the analysis to the bright sources with average hard X-ray fluxes F14 - 195 keV ≥ 2.5 × 10-11erg cm-2 s-1at high Galactic latitudes (|b| > 10°). In order to remove "radio-loud" objects from the sample, we use the "hard X-ray radio loudness parameter," R rX, defined as the ratio of the total 1.4 GHz radio to 14-195 keV hard X-ray energy fluxes. Among 120 X-ray bright Seyfert galaxies with R rX <10-4, we did not find a statistically significant γ-ray excess (TS > 25) positionally coincident with any target Seyferts, with possible exceptions of ESO 323-G077 and NGC6814. The mean value of the 95% confidence level γ-ray upper limit for the integrated photon flux above 100MeV from the analyzed Seyferts is ≃ 4 × 10 -9photons cm-2 s-1, and the upper limits derived for several objects reach ≃ 1 × 10-9photons cm-2 s-1. Our results indicate that no prominent γ-ray emission component related to active galactic nucleus activity is present in the spectra of Seyferts around GeV energies. The Fermi-LAT upper limits derived for our sample probe the ratio of γ-ray to X-ray luminosities Lγ/LX < 0.1, and even <0.01 in some cases. The obtained results impose novel constraints on the models for high-energy radiation of "radio-quiet" Seyfert galaxies. © 2012 The American Astronomical Society. All rights reserved.

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  • Search for dark matter satellites using fermi-LAT

    M. Ackermann, A. Albert, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Essig, L. Falletti, C. Favuzzi, S.J. Fegan, W.B. Focke, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, X. Hou, R.E. Hughes, R.P. Johnson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, A.M. Lionetto, M.L. Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, V. Pelassa, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, H.F.-W. Sadrozinski, N. Sehgal, C. Sgrò, E.J. Siskind, P. Spinelli, L. Strigari, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, L. Tibaldo, M. Tinivella, D.F. Torres, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, S. Zalewski, S. Zimmer

    Astrophysical Journal   747 ( 2 )  2012.03  [Refereed]

     View Summary

    Numerical simulations based on the δCDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites.We report the results of a Large Area Telescope (LAT) search for these satellites via the γ -ray emission expected from the annihilation ofweakly interactingmassive particle (WIMP) darkmatter. Some dark matter satellites are expected to have hard γ -ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on γ -ray spectra consistent with WIMP annihilation through the b-b channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 GeVWIMP annihilating through the b-b channel. © 2012 The American Astronomical Society. All rights reserved.

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  • Discovery of an unidentified Fermi object as a black widow-like millisecond pulsar

    A. K.H. Kong, R. H.H. Huang, K. S. Cheng, J. Takata, Y. Yatsu, C. C. Cheung, D. Donato, L. C.C. Lin, J. Kataoka, Y. Takahashi, K. Maeda, C. Y. Hui, P. H.T. Tam

    Astrophysical Journal Letters   747 ( 1 )  2012.03

     View Summary

    The Fermi γ-ray Space Telescope has revolutionized our knowledge of the γ-ray pulsar population, leading to the discovery of almost 100 γ-ray pulsars and dozens of γ-ray millisecond pulsars (MSPs). Although the outer-gap model predicts different sites of emission for the radio and γ-ray pulsars, until now all of the known γ-ray MSPs have been visible in the radio. Here we report the discovery of a "radio-quiet" γ-ray-emitting MSP candidate by using Fermi, Chandra, Swift, and optical observations. The X-ray and γ-ray properties of the source are consistent with known γ-ray pulsars. We also found a 4.63 hr orbital period in optical and X-ray data. We suggest that the source is a black widow-like MSP with a 0.1 M ⊙ late-type companion star. Based on the profile of the optical and X-ray light curves, the companion star is believed to be heated by the pulsar while the X-ray emissions originate from pulsar magnetosphere and/or from intrabinary shock. No radio detection of the source has been reported yet, and although no γ-ray/radio pulsation has been found we estimate that the spin period of the MSP is 3-5 ms based on the inferred γ-ray luminosity. © 2012 The American Astronomical Society. All rights reserved.

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  • SUZAKU X-RAY FOLLOW-UP OBSERVATIONS OF SEVEN UNASSOCIATED FERMI-LAT GAMMA-RAY SOURCES AT HIGH GALACTIC LATITUDES

    Y. Takahashi, J. Kataoka, T. Nakamori, K. Maeda, R. Makiya, T. Totani, C. C. Cheung, L. Stawarz, L. Guillemot, P. C. C. Freire, I. Cognard

    ASTROPHYSICAL JOURNAL   747 ( 1 ) 64 - 79  2012.03  [Refereed]

     View Summary

    We report on our second-year campaign of X-ray follow-up observations of unidentified Fermi Large Area Telescope (LAT) gamma-ray sources at high Galactic latitudes (vertical bar b vertical bar &gt; 10 degrees) using the X-ray Imaging Spectrometer on board the Suzaku X-ray Observatory. In this second year of the project, seven new targets were selected from the First Fermi-LAT Catalog, and studied with 20-40 ks effective Suzaku exposures. We detected an X-ray point source coincident with the position of the recently discovered millisecond pulsar (MSP) PSR J2302+4442 within the 95% confidence error circle of 1FGL J2302.8+4443. The X-ray spectrum of the detected counterpart was well fit by a blackbody model with temperature of kT similar or equal to 0.3 keV, consistent with an origin of the observed X-ray photons from the surface of a rotating magnetized neutron star. For four other targets that were also recently identified with a normal pulsar (1FGL J0106.7+4853) and MSPs (1FGL J1312.6+0048, J1902.0-5110, and J2043.2+1709), only upper limits in the 0.5-10 keV band were obtained at the flux levels of similar or equal to 10(-14) erg cm(-2) s(-1). A weak X-ray source was found in the field of 1FGL J1739.4+8717, but its association with the variable gamma-ray emitter could not be confirmed with the available Suzaku data alone. For the remaining Fermi-LAT object 1FGL J1743.8-7620 no X-ray source was detected within the LAT 95% error ellipse. We briefly discuss the general properties of the observed high Galactic-latitude Fermi-LAT objects by comparing their multiwavelength properties with those of known blazars and MSPs.

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  • Limits on large extra dimensions based on observations of neutron stars with the Fermi-LAT

    M. Ajello, L. Baldini, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, T. Enoto, C. Favuzzi, S. J. Fegan, E. C. Ferrara, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Graham, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, R. E. Hughes, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, A. M. Lionetto, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, S. Rainò, M. Razzano, S. Ritz, M. Roth, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli

    Journal of Cosmology and Astroparticle Physics   2012 ( 2 )  2012.02

     View Summary

    We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to γγ should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus. © 2012 IOP Publishing Ltd and SISSA.

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  • Development of a scintillation detector using a MPPC as an alternative to an APD

    T. Miura, T. Nakamori, J. Kataoka, T. Kato, K. Sato, Y. Ishikawa, K. Yamamura, N. Kawabata

    JOURNAL OF INSTRUMENTATION   7 ( 2 ) C020306  2012.02  [Refereed]

     View Summary

    We conducted a study to examine the performance of the multi-pixel photon counter(MPPC). The MPPC is a novel type of semiconductor photodetector consisting of multiple avalanche photodiode (APD) pixels operated in Geiger mode. Whereas the MPPC offers a great advantage in signal multiplication comparable to that achieved by the photomultiplier tube (PMT), the detection of weak scintillation light signals is difficult due to the severe contamination of dark counts. In this study, we first compared the energy resolutions and energy thresholds of a 3x3 mm(2) MPPC with those of a 3x3 mm(2) APD as scintillation detectors. The MPPC and APD were optically coupled with 5x5x5 mm(3) scintillation crystals of BGO, Tl:CsI, Pr:LuAG, and YAG. It turned out that the APD had better energy resolutions for 662 keV gamma-rays, while the MPPC had lower energy thresholds as measured using a test pulse. Despite the low energy thresholds, it is difficult for the MPPC to detect low energy gamma-rays due to the contamination of dark counts. Secondly, we applied a coincidence technique to discriminate weak gamma-ray signals from dark counts by using scintillation detectors that consisted of a 2x2 MPPC-array optically coupled with 10x10x10 mm(3) crystals of GSO, BGO, and Pr: LuAG. With this technique, we demonstrated that dark counts achieved a rejection efficiency of more than 99.8%. As a result, 22.2 keV gamma-rays were successfully detected with a GSO scintillator as measured at + 20 degrees C.

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  • EXPLORING THE CENTRAL SUB-PARSEC REGION OF THE gamma-RAY BRIGHT RADIO GALAXY 3C 84 WITH VLBA AT 43 GHz IN THE PERIOD OF 2002-2008

    Kenta Suzuki, Hiroshi Nagai, Motoki Kino, Jun Kataoka, Keiichi Asada, Akihiro Doi, Makoto Inoue, Monica Orienti, Gabriele Giovannini, Marcello Giroletti, Anne Lahteenmaki, Merja Tornikoski, Jonathan Leon-Tavares, Uwe Bach, Seiji Kameno, Hideyuki Kobayashi

    ASTROPHYSICAL JOURNAL   746 ( 2 )  2012.02  [Refereed]

     View Summary

    Following the discovery of a new radio component right before the GeV gamma-ray detection since 2008 August by the Fermi Gamma-ray Space Telescope, we present a detailed study of the kinematics and light curve on the central sub-parsec scale of 3C 84 using the archival Very Long Baseline Array 43 GHz data covering the period between 2002 January and 2008 November. We find that the new component "C3," previously reported by the observations with the Very Long Baseline Interferometer Exploration of Radio Astrometry, was already formed in 2003. The flux density of C3 increases moderately until 2008, and then it becomes brighter rapidly after 2008. The radio core, C1, also shows a similar trend. The apparent speed of C3 with reference to the core C1 shows moderate acceleration from 0.10c to 0.47c between 2003 November and 2008 November, but is still sub-relativistic. We further try to fit the observed broadband spectrum by the one-zone synchrotron self-Compton model using the measured apparent speed of C3. The fit can reproduce the observed gamma-ray emission, but does not agree with the observed radio spectral index between 22 and 43 GHz.

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  • Development of a gamma-ray imager using a large area monolithic 4× 4 MPPC array for a future PET scanner

    Nakamori, T, Kato, T, Kataoka, J, Miura, T, Matsuda, H, Sato, K, Ishikawa, Y, Yamamura, K, Kawabata, N, Ikeda, H, Sato, G, Kamada, K

    Journal of Instrumentaion   7 ( 1 ) C01083 - 13pp  2012.01  [Refereed]

     View Summary

    We report the development of a monolithic MPPC array, which consists of 3 × 3 mm2 elements arranged as a 4 × 4 array manufactured by Hamamatsu applicable to next generation PET scanners. We show that the MPPC is suitable for time of flight PET applications by simple measurement using coincident back-to-back 511 keV gamma rays. We demonstrated that the MPPC has much better timing resolution of ∼ 600 ps than the APD. We coupled the monolithic MPPC array with the Ce:LYSO and Pr:LuAG scintillator matrices as gamma-ray detectors. The energy resolutions were evaluated as ∼ 14% with 662 keV gamma-rays and the Ce:LYSO achieved the best. We also used a resistor network readout circuit with some optimization. The averaged positional resolution is estimated as ∼ 0.27 mm in both x and y directions, while the energy resolution of each pixel was 9.9% for 662 keV gamma rays. Finally we applied the GHz class fast sampling waveform acquisition system to improve performance, and demonstrated efficient noise reduction by the clear detection of 22 keV gamma rays. © 2012 IOP Publishing Ltd and SISSA.

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  • Periodic emission from the gamma-ray binary 1FGL J1018.6-5856

    M. Ackermann, M. Ajello, J. Ballet, G. Barbiellini, D. Bastieri, A. Belfiore, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Corbel, R.H.D. Corbet, S. Cutini, A. De Luca, P.R. Den Hartog, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, D. Donato, P.S. Drell, A. Drlica-Wagner, R. Dubois, G. Dubus, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, A.B. Hill, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T.J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, R.W. Romani, M. Roth, P.M. Saz Parkinson, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, S. Zimmer, M.J. Coe, F. Di Mille, P.G. Edwards, M.D. Filipović, J.L. Payne, J. Stevens, M.A.P. Torres

    Science   335 ( 6065 ) 189 - 193  2012.01  [Refereed]

     View Summary

    Gamma-ray binaries are stellar systems containing a neutron star or black hole, with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy. A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation with a 16.6-day period. We identified a variable x-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an O6V((f)) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. 1FGL J1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.

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  • 13pSP-1 CTA Project 38 : General Report

    Teshima Masahiro

    Meeting Abstracts of the Physical Society of Japan   67.2.1   114  2012

    DOI CiNii

  • Development of a MPPC-based DOI-PET module with submillimeter 3-D resolution

    Aya Kishimoto, Jun Kataoka, Takuya Kato, Takamasa Miura, Takeshi Nakamori, Kei Kamada, Shigeyuki Nakamura, Kenichi Sato, Yoshitaka Ishikawa, Kazuhisa Yamamura, Seiichi Yamamoto

    2012 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE RECORD (NSS/MIC)     3128 - 3133  2012  [Refereed]

     View Summary

    We are proposing a novel design for a module with depth of interaction (DOI) capability for gamma rays by measuring the pulse-height ratio of double-sided Multi-Pixel Photon Counters (MPPCs) coupled at both ends of a scintillation crystal block. Thanks to newly developed monolithic MPPC arrays consisting of 4 x 4 channels with a three-side buttable package, the module is very thin and compact, thereby enabling less dead space between each module when arranged into a fully designed gantry. To demonstrate our concept of a DOI measuring technique, we first made a 1-D crystal array consisting of five Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) cubic crystals measuring 3 x 3 x 3 mm(3) in size, separated by a layer of air. When the light signals output from both ends are read with the MPPCs, the position of each crystal is clearly distinguished with a spatial uncertainty of 0.48 +/- 0.03 mm. For 3-D measurements, we then fabricated three different type arrays: [A] 4 x 4 x 4 matrix of 3 x 3 x 3 mm(3) pixels, [B] 5 x 5 x 5 matrix of 2 x 2 x 2 mm(3) pixels, and [C] 10 x 10 x 10 matrix of 1 x 1 x 1 mm(3) pixels, with each pixel divided by a BaSO4 reflector in the 2-D direction and by a layer of air in the DOI direction. We demonstrated that the 3-D position of each Ce:GAGG pixel was clearly distinguished when illuminated by 662 keV gamma rays uniformly. Average energy resolutions of 9.8 +/- 0.8 %, 9.8 +/- 0.9 %, and 13.2 +/- 1.7 % were obtained for types A, B and C, respectively. These results suggest that our proposed method is simple and offers promise in achieving 1 mm 3-D spatial resolution for future medical imaging, particularly in positron emission tomography (PET).

  • The cosmic-ray and gas content of the Cygnus region as measured in γ-rays by the Fermi Large Area Telescope

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, A. Belfiore, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, A. Chekhtman, S. Ciprini, R. Claus, J. Cohen-Tanugi, A. De Angelis, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, D. Dumora, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, K. Hayashi, E. Hays, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, P. Martin, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron

    Astronomy and Astrophysics   538  2012

     View Summary

    Context. The Cygnus region hosts a giant molecular-cloud complex that actively forms massive stars. Interactions of cosmic rays with interstellar gas and radiation fields make it shine at γ-ray energies. Several γ-ray pulsars and other energetic sources are seen in this direction. Aims. In this paper we analyze the γ-ray emission measured by the Fermi Large Area Telescope (LAT) in the energy range from 100 MeV to 100 GeV in order to probe the gas and cosmic-ray content on the scale of the whole Cygnus complex. The γ-ray emission on the scale of the central massive stellar clusters and from individual sources is addressed elsewhere. Methods. The signal from bright pulsars is greatly reduced by selecting photons in their off-pulse phase intervals. We compare the diffuse γ-ray emission with interstellar gas maps derived from radio/mm-wave lines and visual extinction data. A general model of the region, including other pulsars and γ-ray sources, is sought. Results. The integral H i emissivity above 100 MeV averaged over the whole Cygnus complex amounts to [2.06 ± 0.11 (stat.) -0.84+0.15(syst.)] × 10 -26 photons s -1 sr -1 H-atom -1, where the systematic error is dominated by the uncertainty on the H i opacity to calculate its column densities. The integral emissivity and its spectral energy distribution are both consistent within the systematics with LAT measurements in the interstellar space near the solar system. The average X CO = N(H 2)/W CO ratio is found to be [1.68 ± 0.05 (stat.) -0.10+0.87(HI opacity)] × 10 20 molecules cm -2 (K km s -1) -1, consistent with other LAT measurements in the Local Arm. We detect significant γ-ray emission from dark neutral gas for a mass corresponding to ~40% of what is traced by CO. The total interstellar mass in the Cygnus complex inferred from its γ-ray emission amounts to 8 -1+5 × 10 6 M ⊙ at a distance of 1.4 kpc. Conclusions. Despite the conspicuous star formation activity and high masses of the interstellar clouds, the cosmic-ray population in the Cygnus complex averaged over a few hundred parsecs is similar to that of the local interstellar space. © 2012 ESO.

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  • The ASTRO-H X-ray observatory

    Tadayuki Takahashi, Kazuhisa Mitsuda, Richard Kelley, Henri Aarts, Felix Aharonian, Hiroki Akamatsu, Fumie Akimotoe, Steve Allen, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Makoto Asai, Marc Audard, Hisamitsu Awaki, Philipp Azzarello, Chris Baluta, Aya Bamba, Nobutaka Bando, Mark Bautz, Roger Blandford, Kevin Boyce, Greg Brown, Ed Cackett, Maria Chernyakova, Paolo Coppi, Elisa Costantini, Jelle De Plaa, Jan Willem Den Herder, Michael DiPirro, Chris Done, Tadayasu Dotani, John Doty, Ken Ebisawa, Megan Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew Fabian, Carlo Ferrigno, Adam Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Stefan Funk, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi Gallo, Poshak Gandhi, Keith Gendreau, Kirk Gilmore, Daniel Haas, Yoshito Haba, Kenji Hamaguchi, Isamu Hatsukade, Takayuki Hayashi, Kiyoshi Hayashida, Junko Hiraga, Kazuyuki Hirose, Ann Hornschemeier, Akio Hoshino, John Hughes, Una Hwang, Ryo Iizuka, Yoshiyuki Inoue, Kazunori Ishibashi, Manabu Ishida, Kosei Ishimura, Yoshitaka Ishisaki, Masayuki Ito, Naoko Iwat, Naoko Iyomoto, Jelle Kaastr, Timothy Kallman, Tuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Hajime Kawahara, Madoka Kawaharada, Nobuyuki Kawai, Shigeo Kawasaki, Dmitry Khangaluyan, Caroline Kilbourne, Masashi Kimura, Kenzo Kinugasaa, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Tatsuro Kosaka, Alex Koujelev, Katsuji Koyama, Hans Krimm, Aya Kubota, Hideyo Kunieda, Stephanie LaMass, Philippe Laurent, Francois Lebrun, Maurice Leutenegger, Olivier Limousin, Michael Loewenstein, Knox Long, David Lumb

    Proceedings of SPIE - The International Society for Optical Engineering   8443  2012

     View Summary

    The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-Throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ?E 5 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes. © 2012 SPIE.

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  • Γ-ray emission from the Perseus cluster of galaxies observed with the MAGIC telescopes

    P. Colin, D. Eisenacher, D. Hildebrand, S. Lombardi, E. Lindfors, D. Paneque, S. Partini, F. Prada, J. Sitarek, F. Zandanel, Magic Collaboration, T. Dauser, M. Kadler, F. Krauss, J. Kataoka, C. Pfrommer, A. Pinzke, Y. Takahashi, S. Wilbert, J. Wilms

    AIP Conference Proceedings   1505   578 - 581  2012

     View Summary

    The Perseus cluster of galaxies is a nearby cool-core cluster with an intra-clustermedium (ICM) characterized by very high central densities. The observation of the Perseus cluster with the MAGIC telescopes, during 85 h from 2009 to 2011, resulted in the discovery of 2 point-like sources at very high energy (>100 GeV, VHE) coinciding with the central radio galaxy NGC1275 and the radio galaxy IC310. The γ-ray properties of these 2 sources are presented, taking into account contemporaneous Fermi-LAT as well as multi-wavelength data. Flux variability and spectral energy distribution shapes indicate that the VHE γ-rays do not originate from large-scale interaction of the radio galaxies with ICM but more likely from the active nuclei of these two galaxies. They could be both misaligned version of BL Lac objects, the most common TeV AGN. Our results provide vital clues to understand emission mechanisms of such misaligned objects, and how they may be related to the beamed emission seen in BL Lacs. No evidence of large-scale VHE γ-ray emission from hadronic cosmic ray (CR) interactions with the ICM has been found. The flux upper limit above 1 TeV reaches the signal expected by some theoretical models, constraining the cluster CR physics. In the framework of the hadronicmodel of the radiomini-halos, this limit implies aminimal magnetic field ranging from 4-9μG for the central cluster region. © 2012 American Institute of Physics.

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  • Sub-geiger mode single-photon detector using a low-darkcurrent InGaAs avalanche photodiode

    Yoshito Miyamoto, Kenji Tsujino, Jun Kataoka, Akihisa Tomita

    European Conference on Optical Communication, ECOC    2012

     View Summary

    We have developed a single-photon detector that uses an InGaAs avalanche photodiode (APD) operating in sub-Geiger mode. Sub-Geiger mode operation is a technique in which an APD is operated at a bias voltage that is lower than the breakdown voltage. This mode considerably reduces afterpulse probability, and single photons that arrive randomly can be detected. In the present study, we reduced the dark count rate of the sub-Geiger mode single-photon detector by using a low-darkcurrent InGaAs APD. Consequently, we obtained a dark count rate (DCR) of 5.6 counts per second (cps) with single-photon detection efficiency (SPDE) of 0.2%. Our single-photon detector is comparable in DCR to that of superconducting nanowire single-photon detectors. © 2012 OSA.

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  • In-flight measurement of the absolute energy scale of the Fermi Large Area Telescope

    M. Ackermann, M. Ajello, A. Allafort, W.B. Atwood, M. Axelsson, L. Baldini, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, T. Enoto, L. Falletti, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T.J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, S. Rain, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, C. Sgr, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, D.J. Suson, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, G. Tosti, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, S. Zimmer

    Astroparticle Physics   35 ( 6 ) 346 - 353  2012.01  [Refereed]

     View Summary

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between ∼6 and ∼13 GeV with an estimated uncertainty of ∼2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars. © 2011 Elsevier B.V. All rights reserved.

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  • Fermi Large Area Telescope observations of the supernova remnant G8.7-0.1

    M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, Y. Fukazawa, Y. Fukui, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, E. Hays, R. Itoh, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, H. Kubo, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, A.M. Lionetto, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, M.N. Mazziotta, J. Mehault, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, A. Reimer, O. Reimer, T. Reposeur, M. Roth, H.F.-W. Sadrozinski, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, A. Van Etten, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, H. Yamamoto, R. Yamazaki, Z. Yang, H. Yasuda, M. Ziegler, S. Zimmer

    Astrophysical Journal   744 ( 1 )  2012.01  [Refereed]

     View Summary

    We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. TheGeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200MeV-100GeV can be described by a broken power-law function with a break of 2.4 ± 0.6 (stat) ± 1.2 (sys)GeV, and photon indices of 2.10 ± 0.06 (stat) ± 0.10 (sys) below the break and 2.70 ± 0.12 (stat) ± 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of π0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains theGeV gamma-ray spectrum. We also find that theGeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in theGeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.

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  • Measurement of separate cosmic-ray electron and positron spectra with the fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, W.B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, A.K. Harding, M. Hayashida, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, C. Sbarra, T.L. Schalk, C. Sgrò, E.J. Siskind, G. Spandre, P. Spinelli, A.W. Strong, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, M. Wood, Z. Yang, S. Zimmer

    Physical Review Letters   108 ( 1 )  2012  [Refereed]

     View Summary

    We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting Earth's shadow, which is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 GeV. We confirm that the fraction rises with energy in the 20-100 GeV range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy. © 2012 American Physical Society.

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  • Soft Gamma-ray Detector for the ASTRO-H mission

    Watanabe Shin, Talima Hiroyasu, Fukazawa Yasushi, Blandford Roger, Enoto Teruaki, Kataoka Jun, Kawaharada Madoka, Kokubun Motohide, Laurent Philippe, Lebrun Francois, Limousin Olivier, Madejski Greg, Makishima Kazuo, Mizuno Tsunefumi, Nakamori Takeshi, Nakazawa Kazuhiro, Mori Kunishiro, Odaka Hirokazu, Ohno Masanori, Ohta Masayuki, Sato Goro, Sato Rie, Takeda Shin'ichiro, Takahashi Hiromitsu, Takahashi Tadayuki, Tanaka Takaaki, Tashiro Makoto, Terada Yukikatsu, Uchiyama Hideki, Uchiyama Yasunobu, Yamada Shinya, Yatsu Yoichi, Yonetoku Daisuke, Yuasa Takayuki

    SPACE TELESCOPES AND INSTRUMENTATION 2012: ULTRAVIOLET TO GAMMA RAY   8443  2012  [Refereed]

     View Summary

    ASTRO-H is the next generation JAXA X-ray satellite, intended to carry instruments with broad energy coverage and exquisite energy resolution. The Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature wide energy band (60-600 keV) at a background level 10 times better than the current instruments on orbit. The SGD is complimentary to ASTRO-H's Hard X-ray Imager covering the energy range of 5-80 keV. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield where Compton kinematics is utilized to reject backgrounds. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is afforded by semiconductor sensors, and it results in good background rejection capability due to better constraints on Compton kinematics. Utilization of Compton kinematics also makes the SGD sensitive to the gamma-ray polarization, opening up a new window to study properties of gamma-ray emission processes. In this paper, we will present the detailed design of the SGD and the results of the final prototype developments and evaluations. Moreover, we will also present expected performance based on the measurements with prototypes. © 2012 SPIE.

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  • フェルミ・バブルから探る銀河系中心の過去の活動性

    片岡 淳, 戸谷 友則, 井岡 邦仁

    日本天文学会誌   105 ( 9 ) 542 - 553  2012

    CiNii

  • The second catalog of active galactic nuclei detected by the Fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, E. Antolini, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, L. Escande, C. Favuzzi, S.J. Fegan, E.C. Ferrara, J. Finke, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, S.E. Healey, D. Horan, X. Hou, R.E. Hughes, G. Iafrate, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, M.N. Mazziotta, W. McConville, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, S. Piranomonte, F. Piron, G. Pivato, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, S. Ritz, L.S. Rochester, R.W. Romani, M. Roth, D.A. Sanchez, C. Sbarra, J.D. Scargle, T.L. Schalk, C. Sgrò, M.S. Shaw, E.J. Siskind, G. Spandre, P. Spinelli, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, D.L. Wood, K.S. Wood, S. Zimmer

    Astrophysical Journal   743 ( 2 )  2011.12  [Refereed]

     View Summary

    The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The second LAT AGN catalog (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. However, some of these are affected by analysis issues and some are associated with multiple AGNs. Consequently, we define a Clean Sample which includes 886 AGNs, comprising 395 BLLacertae objects (BLLac objects), 310 flat-spectrum radio quasars (FSRQs), 157 candidate blazars of unknown type (i.e., with broadband blazar characteristics but with no optical spectral measurement yet), 8 misaligned AGNs, 4 narrow-line Seyfert 1 (NLS1s), 10 AGNs of other types, and 2 starburst galaxies. Where possible, the blazars have been further classified based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. While almost all FSRQs have a synchrotron-peak frequency <1014 Hz, about half of the BLLac objects have a synchrotron-peak frequency >1015 Hz. The 2LAC represents a significant improvement relative to the first LAT AGN catalog (1LAC), with 52% more associated sources. The full characterization of the newly detected sources will require more broadband data. Various properties, such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities and their correlations are presented and discussed for the different blazar classes. The general trends observed in 1LAC are confirmed. © 2011 The American Astronomical Society. All rights reserved.

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  • Constraining dark matter models from a combined analysis of Milky Way satellites with the Fermi Large Area Telescope

    M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, B. Cañadas, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S. J. Fegan, E. C. Ferrara, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, R. E. Hughes, T. E. Jeltema, G. Jóhannesson, R. P. Johnson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, A. M. Lionetto, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura

    Physical Review Letters   107 ( 24 )  2011.12

     View Summary

    Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10-26cmm3s-1 at 5 GeV to about 5×10-23cm3s-1 at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (∼3×10-26cm3s-1 for a purely s-wave cross section), without assuming additional boost factors. © 2011 American Physical Society.

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  • シンポジウム「二次元放射線検出器の最前線」開催への思い

    片岡 淳

    放射線   37 ( 4 ) 215 - 215  2011.12

    CiNii

  • Gas slit camera (GSC) onboard MAXI on ISS

    Tatehiro Mihara, Motoki Nakajima, Mutsumi Sugizaki, Motoko Serino, Masaru Matsuoka, Mitsuhiro Kohama, Kazuyoshi Kawasaki, Hiroshi Tomida, Shiro Ueno, Nobuyuki Kawai, Jun Kataoka, Mikio Morii, Atsumasa Yoshida, Kazutaka Yamaoka, Satoshi Nakahira, Hitoshi Negoro, Naoki Isobe, Makoto Yamauchi, Ikuya Sakurai

    Publications of the Astronomical Society of Japan   63 ( SPEC. ISSUE 3 )  2011.11

     View Summary

    The Gas Slit Camera (GSC) is an X-ray instrument on the MAXI (Monitor of All-sky X-ray Image) mission aboard the International Space Station. It is designed to scan the entire sky every 92-minute orbital period in the 2-30 keV band and to achieve the highest sensitivity among the X-ray all-sky monitors ever flown so far. The GSC employs large-area position-sensitive proportional counterswith a total detector area of 5350cm2. The on-board data processor has functions to format telemetry data as well as to control the high voltage of the proportional counters so as to protect them from particle irradiation. This paper describes the instruments, on-board data processing, telemetry data formats, and performance specifications expected from ground calibration tests. © 2011. Astronomical Society of Japan.

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    154
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  • A cocoon of freshly accelerated cosmic rays detected by fermi in the cygnus superbubble

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, A. Belfiore, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, E. Bottacini, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, D. Dumora, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, K. Hayashi, E. Hays, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, P. Martin, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, M. Pohl, D. Prokhorov, S. Rainò, R. Rando, M. Razzano, T. Reposeur, S. Ritz, P.M. Saz Parkinson, C. Sgrò, E.J. Siskind, P.D. Smith, P. Spinelli, A.W. Strong, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, S. Zimmer, S. Bontemps

    Science   334 ( 6059 ) 1103 - 1107  2011.11  [Refereed]

     View Summary

    The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population.

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  • Fermi detection of a luminous γ-ray pulsar in a globular cluster

    P.C.C. Freire, A.A. Abdo, M. Ajello, A. Allafort, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, F. De Palma, C.D. Dermer, E. Do Couto E Silva, M. Dormody, P.S. Drell, R. Dubois, D. Dumora, C.M. Espinoza, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, G. Jóhannesson, A.S. Johnson, T.J. Johnson, S. Johnston, H. Katagiri, J. Kataoka, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A.G. Lyne, R.N. Manchester, M. Marelli, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, S.M. Ransom, P.S. Ray, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, P.M. Saz Parkinson, C. Sgrò, R. Shannon, E.J. Siskind, D.A. Smith, P.D. Smith, P. Spinelli, B.W. Stappers, D.J. Suson, H. Takahashi, T. Tanaka, T.M. Tauris, J.B. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, E. Troja, J. Vandenbroucke, A. Van Etten, V. Vasileiou, C. Venter, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K.S. Wood, Z. Yang, M. Ziegler, S. Zimmer

    Science   334 ( 6059 ) 1107 - 1110  2011.11  [Refereed]

     View Summary

    We report on the Fermi Large Area Telescope's detection of γ-ray (>100 mega-electron volts) pulsations from pulsar J1823-3021A in the globular cluster NGC 6624 with high significance (∼7 σ). Its γ-ray luminosity, Lγ = (8.4 ± 1.6) × 1034 ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The nondetection of the cluster in the off-pulse phase implies that it contains <32 γ-ray MSPs, not ∼100 as previously estimated. The γ-ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823-3021A has the largest magnetic field and is the youngest MSP ever detected and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.

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    70
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  • γ -Ray and parsec-scale jet properties of a complete sample of blazars from the mojave program

    M. L. Lister, M. Aller, H. Aller, T. Hovatta, K. I. Kellermann, Y. Y. Kovalev, E. T. Meyer, A. B. Pushkarev, E. Ros, M. Ackermann, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, M. Boeck, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, C. S. Chang, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, W. B. Focke, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, G. Jóhannesson, A. S. Johnson, M. Kadler, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. N. Mazziotta, W. McConville, J. E. McEnery, J. Mehault, P. F. Michelson, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino

    Astrophysical Journal   742 ( 1 )  2011.11

     View Summary

    We investigate the Fermi Large Area Telescope γ -ray and 15 GHz Very Long Baseline Array radio properties of a joint γ -ray and radio-selected sample of active galactic nuclei (AGNs) obtained during the first 11 months of the Fermi mission (2008 August 4-2009 July 5). Our sample contains the brightest 173 AGNs in these bands above declination -30° during this period, and thus probes the full range of γ -ray loudness (γ -ray to radio band luminosity ratio) in the bright blazar population. The latter quantity spans at least 4 orders of magnitude, reflecting a wide range of spectral energy distribution (SED) parameters in the bright blazar population. The BL Lac objects, however, display a linear correlation of increasing γ -ray loudness with synchrotron SED peak frequency, suggesting a universal SED shape for objects of this class. The synchrotron self-Compton model is favored for the γ -ray emission in these BL Lac objects over external seed photon models, since the latter predict a dependence of Compton dominance on Doppler factor that would destroy any observed synchrotron SED-peak-γ -ray-loudness correlation. The high-synchrotron peaked (HSP) BL Lac objects are distinguished by lower than average radio core brightness temperatures, and none display large radio modulation indices or high linear core polarization levels. No equivalent trends are seen for the flat-spectrum radio quasars (FSRQs) in our sample. Given the association of such properties with relativistic beaming, we suggest that the HSP BL Lac objects have generally lower Doppler factors than the lower-synchrotron peaked BL Lac objects or FSRQs in our sample.

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  • The radio/gamma-ray connection in active galactic nuclei in the era of the fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, E. Angelakis, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, L. Escande, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, S.E. Healey, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, V. Pavlidou, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, M. Razzano, A. Readhead, A. Reimer, O. Reimer, J.L. Richards, R.W. Romani, H.F.-W. Sadrozinski, J.D. Scargle, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, G.B. Taylor, J.G. Thayer, J.B. Thayer, D.J. Thompson, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, J. Vandenbroucke, G. Vianello, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, M. Ziegler

    Astrophysical Journal   741 ( 1 )  2011.11  [Refereed]

     View Summary

    We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the active galactic nuclei (AGNs) detected by Fermi during its first year of operation, with the largest data sets ever used for this purpose. We use both archival interferometric 8.4GHz data (from the Very Large Array and ATCA, for the full sample of 599 sources) and concurrent single-dish 15GHz measurements from the Owens Valley Radio Observatory (OVRO, for a sub sample of 199 objects). Our unprecedentedly large sample permits us to assess with high accuracy the statistical significance of the correlation, using a surrogate data method designed to simultaneously account for common-distance bias and the effect of a limited dynamical range in the observed quantities. We find that the statistical significance of a positive correlation between the centimeter radio and the broadband (E > 100MeV) gamma-ray energy flux is very high for the whole AGN sample, with a probability of <10 -7 for the correlation appearing by chance. Using the OVRO data, we find that concurrent data improve the significance of the correlation from 1.6 × 10-6 to 9.0 × 10-8. Our large sample size allows us to study the dependence of correlation strength and significance on specific source types and gamma-ray energy band. We find that the correlation is very significant (chance probability < 10-7) for both flat spectrum radio quasars and BL Lac objects separately; a dependence of the correlation strength on the considered gamma-ray energy band is also present, but additional data will be necessary to constrain its significance. © 2011. The American Astronomical Society. All rights reserved.

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    125
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  • BROAD-LINE RADIO GALAXIES OBSERVED WITH FERMI-LAT: THE ORIGIN OF THE GeV gamma-RAY EMISSION

    J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

    ASTROPHYSICAL JOURNAL   740 ( 1 )  2011.10

     View Summary

    We report on a detailed investigation of the gamma-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is &gt;= 1% on average for BLRGs, whereas it is &lt;= 0.1% for Seyfert 1 galaxies.

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    74
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  • BROAD-LINE RADIO GALAXIES OBSERVED WITH FERMI-LAT: THE ORIGIN OF THE GeV gamma-RAY EMISSION

    J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

    ASTROPHYSICAL JOURNAL   740 ( 1 ) 29 - 44  2011.10  [Refereed]

     View Summary

    We report on a detailed investigation of the gamma-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is &gt;= 1% on average for BLRGs, whereas it is &lt;= 0.1% for Seyfert 1 galaxies.

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    74
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  • Development micro-satellite TSUBAME for polarimetry of gamma-ray bursts

    Yatsu, Y, Enomoto, T, Kawakami, K, Tokoyoda, K, Toizumi, T, Kawai, N, Ishizaka, K, Matsunaga, S, Nakamori, T, Kataoka, J, Kubo, S

    Proc. of SPIE   8145   814508  2011.09

     View Summary

    Gamma-ray bursts (GRBs) are the most drastic and intriguing phenomena in high energy astrophysics. The nature of relativistic collimated outflows that bight be generated by gravitational collapses of massive stars is to investigate the physical process just around the central engines by constraining magnetic environment. For this purpose we developed a compact and high sensitive hard x-ray polarimeter aboard a university class micro-satellite "TSUBAME." Unsurprisingly, any micro-satellites have stringent limitations on size, mass, and power consumption restricting the effective area of detectors. However, high luminosities of GRBs allow us to measure their polarizations only if we start observations just after the ignitions. TSUBAME overcomes this problem by using compact an high-torque actuators, control moment gyroscopes, that enable high speed attitude control faster than 6°s-1. Cooperating with a wide field burst monitor on board for real time position determination of GRBs, TSUBAME can start a pointing observation within ∼15 s after the detection for any GRBs in the half-sky field of view of the burst monitor. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

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    4
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  • Improvement of Energy Thresholds for Scintillation Detectors Using a Monolithic 2 x 2 Multi-Pixel Photon Counter Array with a Coincidence Technique

    Takamasa Miura, Takeshi Nakamori, Jun Kataoka, Takuya Kato, Kenichi Sato, Yoshitaka Ishikawa, Kazuhisa Yamamura, Nobuyuki Kawabata

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( 9 )  2011.09

     View Summary

    The performance of a large-area, monolithic Hamamatsu multi-pixel photon counter (MPPC) was tested consisting of a 2 x 2 array of 3 x 3 mm(2) pixels. MPPC is a novel type of semiconductor photodetector comprising multiple avalanche photodiode (APD) pixels operated in Geiger mode. Despite its great advantage of signal multiplication comparable to that achieved with the photomultiplier tube (PMT), the detection of weak scintillation light signals is quite difficult due to the severe contamination of dark counts, which typically amounts to similar or equal to 1 Mcps/3 x 3 mm(2) at room temperature. In this study, a coincidence technique was applied for scintillation detectors to improve the detection efficiency for low energy gamma-rays. The detector consisted of a 10 x 10 x 10 mm(3) crystals of GSO, BGO, and Pr:LuAG optically coupled with the 2 x 2 MPPC-array. With this technique, we demonstrated that the contamination of dark counts was reduced with a rejection efficiency of more than 99.8%. As a result, 22.2 keV gamma-rays were successfully detected with a GSO scintillator as measured at +20 degrees C.

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  • Improvement of Energy Thresholds for Scintillation Detectors Using a Monolithic 2 x 2 Multi-Pixel Photon Counter Array with a Coincidence Technique

    Takamasa Miura, Takeshi Nakamori, Jun Kataoka, Takuya Kato, Kenichi Sato, Yoshitaka Ishikawa, Kazuhisa Yamamura, Nobuyuki Kawabata

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( 9 ) 094203  2011.09  [Refereed]

     View Summary

    The performance of a large-area, monolithic Hamamatsu multi-pixel photon counter (MPPC) was tested consisting of a 2 x 2 array of 3 x 3 mm(2) pixels. MPPC is a novel type of semiconductor photodetector comprising multiple avalanche photodiode (APD) pixels operated in Geiger mode. Despite its great advantage of signal multiplication comparable to that achieved with the photomultiplier tube (PMT), the detection of weak scintillation light signals is quite difficult due to the severe contamination of dark counts, which typically amounts to similar or equal to 1 Mcps/3 x 3 mm(2) at room temperature. In this study, a coincidence technique was applied for scintillation detectors to improve the detection efficiency for low energy gamma-rays. The detector consisted of a 10 x 10 x 10 mm(3) crystals of GSO, BGO, and Pr:LuAG optically coupled with the 2 x 2 MPPC-array. With this technique, we demonstrated that the contamination of dark counts was reduced with a rejection efficiency of more than 99.8%. As a result, 22.2 keV gamma-rays were successfully detected with a GSO scintillator as measured at +20 degrees C.

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  • The Small Satellite ``Tsubame'' for Polarimetry of GRBs

    Toizumi, T, Kawakami, K, Tokoyoda, K, Enomoto, T, Yatsu, Y, Kawai, N, Nakamori, T, Kataoka, J, Kubo, S

    AIP Conference Proceedings   1357   355 - 357  2011.08

     View Summary

    "Tsubame" is a university-built small satellite mission that measures polarization of hard X-ray photons (30-100 keV) from gamma-ray bursts (GRB) using azimuthal angle anisotropy of Compton scattering. The satellite is intended for a piggy-back launch on the H-IIA rocket. It uses Control moment gyros to quickly orient itself to GRBs within 15 seconds from triggers. We are now developing the engineering model of the two detector systems on Tsubame, the polarimeter and the bust monitor. In this paper, we present an overview of the Tsubame mission, and detail of development of engineering model of our polarimeter and burst monitor. © 2011 American Institute of Physics.

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  • Constraints on dark matter models from a Fermi LAT search for high-energy cosmic-ray electrons from the Sun

    M. Ajello, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, C. Cecchi, E. Charles, A. Chekhtman, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, C. Favuzzi, S. J. Fegan, W. B. Focke, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, G. Iafrate, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kuss, L. Latronico, A. M. Lionetto, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, M. Pesce-Rollins, M. Pierbattista, F. Piron, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, T. L. Schalk, C. Sgrò, J. Siegal-Gaskins, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, D. J. Suson

    Physical Review D - Particles, Fields, Gravitation and Cosmology   84 ( 3 )  2011.08

     View Summary

    During its first year of data taking, the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope has collected a large sample of high-energy cosmic-ray electrons and positrons (CREs). We present the results of a directional analysis of the CRE events, in which we searched for a flux excess correlated with the direction of the Sun. Two different and complementary analysis approaches were implemented, and neither yielded evidence of a significant CRE flux excess from the Sun. We derive upper limits on the CRE flux from the Sun's direction, and use these bounds to constrain two classes of dark matter models which predict a solar CRE flux: (1) models in which dark matter annihilates to CREs via a light intermediate state, and (2) inelastic dark matter models in which dark matter annihilates to CREs. © 2011 American Physical Society.

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  • Fermi large area telescope observations of Markarian 421: The missing piece of its spectral energy distribution

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, L. Escande, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, T. Fukuyama, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, J.E. Mcenery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pavlidou, T.J. Pearson, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, L.C. Reyes, J.L. Richards, S. Ritz, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, Ł. Stawarz, M. Stevenson, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, A.E. Wehrle, B.L. Winer, K.S. Wood, Z. Yang, Y. Yatsu, T. Ylinen, J.A. Zensus, M. Ziegler, J. Aleksić, L.A. Antonelli, P. Antoranz, M. Backes, J.A. Barrio, J.B. González, W. Bednarek, A. Berdyugin, K. Berger, E. Bernardini, A. Biland, O. Blanch, R.K. Bock, A. Boller, G. Bonnoli, P. Bordas, D.B. Tridon, V. Bosch-Ramon, D. Bose, I. Braun, T. Bretz, M. Camara, E. Carmona, A. Carosi, P. Colin, E. Colombo, J.L. Contreras, J. Cortina, S. Covino, F. Dazzi, A. De Angelis, E. De Cea Del Pozo, C.D. Mendez, B. De Lotto, M. De Maria, F. De Sabata, A.D. Ortega, M. Doert, A. Domínguez, D.D. Prester, D. Dorner, M. Doro, D. Elsaesser, D. Ferenc, M.V. Fonseca, L. Font, R.J.G. López, M. Garczarczyk, M. Gaug, G. Giavitto, N. Godinovi, D. Hadasch, A. Herrero, D. Hildebrand, D. Höhne-Mönch, J. Hose, D. Hrupec, T. Jogler, S. Klepser, T. Krä

    Astrophysical Journal   736 ( 2 )  2011.08  [Refereed]

     View Summary

    We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk421) during the first 1.5years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3GeV can be well described by a power-law function with photon index Γ = 1.78 0.02 and average photon flux F(> 0.3GeV) = (7.23 0.16) × 10-8phcm-2s -1. Over this time period, the Fermi-LAT spectrum above 0.3GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor 3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk421 showed a low activity at all wavebands. The extensive multi-instrument (radio toTeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site. © 2011. The American Astronomical Society. All rights reserved.

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  • The Small Satellite ``Tsubame'' for Polarimetry of GRBs

    Toizumi, T, Kawakami, K, Tokoyoda, K, Enomoto, T, Yatsu, Y, Kawai, N, Nakamori, T, Kataoka, J, Kubo, S

    AIP Conference Proceedings   1358   435 - 437  2011.08

     View Summary

    "Tsubame" is a university-built small satellite mission that measures polarization of hard X-ray photons (30-100 keV) from gamma-ray bursts (GRB) using azimuthal angle anisotropy of Compton scattering. The satellite is intended for a piggy-back launch on the H-IIA rocket. It uses Control moment gyros to quickly orient itself to GRBs within 15 seconds from triggers. We are now developing the engineering model of the two detector systems on Tsubame, the polarimeter and the bust monitor. In this paper, we present an overview of the Tsubame mission, and detail of development of engineering model of our polarimeter and burst monitor. © 2011 American Institute of Physics.

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    1
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  • Discovery of high-energy gamma-ray emission from the binary system PSR B1259-63/LS 2883 around periastron with Fermi

    A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, M. Chernyakova, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, S. Corbel, S. Cutini, F. D'Ammando, A. De Angelis, P. R. Den Hartog, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, M. Dormody, P. S. Drell, A. Drlica-Wagner, R. Dubois, G. Dubus, D. Dumora, T. Enoto, C. M. Espinoza, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, E. Grundstrom, S. Guiriec, C. Gwon, D. Hadasch, A. K. Harding, M. Hayashida, E. Hays, G. Jóhannesson, A. S. Johnson, T. J. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, R. N. Manchester, M. Marelli, M. N. Mazziotta

    Astrophysical Journal Letters   736 ( 1 )  2011.07

     View Summary

    We report on the discovery of ≥100MeV γ-rays from the binary system PSR B1259-63/LS 2883 using the Large Area Telescope (LAT) on board Fermi. The system comprises a radio pulsar in orbit around a Be star. We report on LAT observations from near apastron to ∼128 days after the time of periastron, ∼tp , on 2010 December 15. No γ-ray emission was detected from this source when it was far from periastron. Faint γ-ray emission appeared as the pulsar approached periastron. At ∼tp + 30 days, the ≥100MeV γ-ray flux increased over a period of a few days to a peak flux 20-30 times that seen during the pre-periastron period, but with a softer spectrum. For the following month, it was seen to be variable on daily timescales, but remained at ∼(1-4) × 10-6 cm-2 s-1 before starting to fade at ∼tp + 57 days. The total γ-ray luminosity observed during this period is comparable to the spin-down power of the pulsar. Simultaneous radio and X-ray observations of the source showed no corresponding dramatic changes in radio and X-ray flux between the pre-periastron and post-periastron flares. We discuss possible explanations for the observed γ-ray-only flaring of the source. © 2011. The American Astronomical Society. All rights reserved.

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  • The development and performance of UV-enhanced APD-arrays for high resolution PET imaging coupled with pixelized Pr: LuAG crystal

    Yoshino, M, Kataoka, J, Nakamori, T, Matsuda, H, Miura, T, Katou, T, Ishikawa, Y, Kawabata, N, Matsunaga, Y, Kamada, K, Usuki, Y, Yoshikawa, A, Yanagida, T

    Nuclear Instruments and Methods in Physics Research Section A   643 ( 1 ) 57 - 63  2011.07  [Refereed]

     View Summary

    The development of high-resolution, UV-enhanced avalanche photodiode (APD) arrays usable in high-resolution PET imaging is underway. These APD arrays were specifically designed as photosensors capable of direct coupling with pixelized Pr-doped Lu3Al5O12 (Pr:LuAG) scintillators. An excellent quantum efficiency (QE) of 55% was achieved at the peak emission of Pr:LuAG (310 nm), namely, a substantial improvement from the QE ≤5% as measured with the conventional Hamamatsu reverse-type APDs (S8664 series). Each APD device has 8×8 (TYP1) and 12×12 (TYP2) pixel structures with active areas of 3×3 mm2 and 2×2 mm2 in each pixel, respectively. A gain uniformity of ±8% and low dark noise of ≤2nA/pixel have been achieved, measured at 25 °C. We also report on the large size single crystal growth of improved Pr:LuAG scintillators and the preliminary performance test of the same. An energy resolution of 4.2% (FWHM) was obtained for 662 keV gamma-rays for 10×10×10 mm3 crystal, measured with a PMT employing a super-bialkali photocathode. We made a test module consisting of a UV-enhanced APD-array (either TYP1 or TYP2) optically coupled with an 8×8 (or 12×12) pixel Pr:LuAG matrix. The linearity between the output signals and incident gamma-ray energy of TYP1 and TYP2 gamma-ray detectors were only 0.27 and 0.33%, as measured at 25 °C for various gamma-ray sources, respectively. Energy resolutions of 7.0±0.2% (FWHM) and 9.0±0.6% (FWHM) were, respectively, obtained for TYP1 and TYP2 detector arrays for 662 keV gamma-rays. The uniformity of the pulse height distributions was also measured at less than 8% for both detectors. Finally, we measured the coincidence timing resolution of these gamma-ray detectors and obtained 4.0±0.1 ns (FWHM) for the 511 keV annihilation quanta from a 22Na source. These results suggest that UV-enhanced APD-arrays coupled with Pr:LuAG scintillators could be a promising device for future application in nuclear medicine. © 2011 Elsevier B.V. All rights reserved.

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  • Detection of high-energy gamma-ray emission during the X-ray flaring activity in GRB 100728A

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R.D. Blandford, E. Bonamente, J. Bonnell, A.W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, V. Connaughton, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, J. Granot, I.A. Grenier, S. Guiriec, D. Hadasch, Y. Hanabata, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, B. Lott, P. Lubrano, M.N. Mazziotta, J.E. McEnery, P. Mészros, P.F. Michelson, T. Mizuno, A.A. Moiseev, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, W.S. Paciesas, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, J.L. Racusin, S. Rainò, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L.C. Reyes, M. Roth, H.F.-W. Sadrozinski, C. Sgrò, E.J. Siskind, P.D. Smith, E. Sonbas, G. Spandre, P. Spinelli, M. Stamatikos, M.S. Strickman, H. Takahashi, T. Tanaka, Y. Tanaka, J.G. Thayer, J.B. Thayer, D.F. Torres, G. Tosti, E. Troja, T. Uehara, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, R. Yamazaki, Z. Yang, M. Ziegler, L. Piro

    Astrophysical Journal Letters   734 ( 2 )  2011.06  [Refereed]

     View Summary

    We present the simultaneous Swift and Fermi observations of the bright GRB 100728A and its afterglow. The early X-ray emission is dominated by a vigorous flaring activity continuing until 1ks after the burst. In the same time interval, high-energy emission is significantly detected by the Fermi/Large Area Telescope. Marginal evidence ofGeV emission is observed up to later times. We discuss the broadband properties of this burst within both the internal and external shock scenarios, with a particular emphasis on the relation between X-ray flares, theGeV emission, and a continued long-duration central engine activity as their power source. © 2011. The American Astronomical Society. All rights reserved.

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  • Fermi large area telescope observations of two gamma-ray emission components from the quiescent sun

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, L. Grillo, S. Guiriec, D. Hadasch, E. Hays, R.E. Hughes, G. Iafrate, G. Jóhannesson, A.S. Johnson, T.J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, A.M. Lionetto, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, H.F.-W. Sadrozinski, T.L. Schalk, C. Sgrò, G.H. Share, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, H. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.E. Vladimirov, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, M. Ziegler

    Astrophysical Journal   734 ( 2 )  2011.06  [Refereed]

     View Summary

    We report the detection of high-energy γ-rays from the quiescent Sun with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope (Fermi) during the first 18 months of the mission. These observations correspond to the recent period of low solar activity when the emission induced by cosmic rays (CRs) is brightest. For the first time, the high statistical significance of the observations allows clear separation of the two components: the point-like emission from the solar disk due to CR cascades in the solar atmosphere and extended emission from the inverse Compton (IC) scattering of CR electrons on solar photons in the heliosphere. The observed integral flux (≥100MeV) from the solar disk is (4.6 ± 0.2[statistical error] +1.0- 0.8[systematic error]) × 10 -7cm-2s-1, which is 7 times higher than predicted by the "nominal" model of Seckel etal. In contrast, the observed integral flux (≥100MeV) of the extended emission from a region of 20° radius centered on the Sun, but excluding the disk itself, (6.8 ± 0.7[stat.]+0.5- 0.4[syst.]) × 10 -7cm-2s-1, along with the observed spectrum and the angular profile, is in good agreement with the theoretical predictions for the IC emission. © 2011. The American Astronomical Society. All rights reserved.

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  • Observations of the young supernova remnant RX J1713.7-3946 with the Fermi Large Area Telescope

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Corbel, S. Cutini, A. De Angelis, F. De Palma, C.D. Dermer, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Favuzzi, E.C. Ferrara, P. Fortin, M. Frailis, Y. Fukazawa, Y. Fukui, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, K. Hayashi, E. Hays, D. Horan, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, R.P. Mignani, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pesce-Rollins, M. Pierbattista, F. Piron, M. Pohl, T.A. Porter, S. Rainò, R. Rando, M. Razzano, O. Reimer, T. Reposeur, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, P.M. Saz Parkinson, C. Sgrò, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, J.B. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, H. Yamamoto, R. Yamazaki, Z. Yang, M. Ziegler

    Astrophysical Journal   734 ( 1 )  2011.06  [Refereed]

     View Summary

    We present observations of the young supernova remnant (SNR) RXJ1713.7-3946 with the Fermi Large Area Telescope (LAT). We clearly detect a source positionally coincident with the SNR. The source is extended with a best-fit extension of 055 ± 004 matching the size of the non-thermal X-ray and TeV gamma-ray emission from the remnant. The positional coincidence and the matching extended emission allow us to identify the LAT source with SNR RXJ1713.7-3946. The spectrum of the source can be described by a very hard power law with a photon index of Γ = 1.5 0.1 that coincides in normalization with the steeper H.E.S.S.-detected gamma-ray spectrum at higher energies. The broadband gamma-ray emission is consistent with a leptonic origin as the dominant mechanism for the gamma-ray emission. © 2011. The American Astronomical Society. All rights reserved.

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  • Fermi gamma-ray space telescope observations of the gamma-ray outburst from 3C454.3 in November 2010

    A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, L. Escande, C. Favuzzi, S. J. Fegan, E. C. Ferrara, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R. Itoh, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, S. H. Lee, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, W. McConville, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino

    Astrophysical Journal Letters   733 ( 2 PART 2 )  2011.06

     View Summary

    The flat-spectrum radio quasar 3C454.3 underwent an extraordinary 5 day γ-ray outburst in 2010 November when the daily flux measured with the Fermi Large Area Telescope (LAT) at photon energies E > 100MeV reached (66 2) × 10-6 photons cm-2 s-1. This is a factor of three higher than its previous maximum flux recorded in 2009 December and ≳ 5 times brighter than the Vela pulsar, which is normally the brightest source in the γ-ray sky. The 3hr peak flux was (85 5)×10-6 photons cm-2 s-1, corresponding to an apparent isotropic luminosity of (2.1 0.2)×1050 erg s-1, the highest ever recorded for a blazar. In this Letter, we investigate the features of this exceptional event in the γ-ray band of the Fermi-LAT. In contrast to previous flares of the same source observed with the Fermi-LAT, clear spectral changes are observed during the flare. © 2011. The American Astronomical Society. All rights reserved.

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  • Development of a large-area monolithic 4 x 4 MPPC array for a future PET scanner employing pixelized Ce:LYSO and Pr:LuAG crystals

    T. Kato, J. Kataoka, T. Nakamori, T. Miura, H. Matsuda, K. Sato, Y. Ishikawa, K. Yamamura, N. Kawabata, H. Ikeda, G. Sato, K. Kamada

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   638 ( 1 ) 83 - 91  2011.05  [Refereed]

     View Summary

    We have developed a new type of large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of a 4 x 4 matrix of 3 x 3 mm(2) pixels. Each pixel comprises 3600 Geiger mode avalanche photodiodes (APDs) that achieve an average gain of 9.68 x 10(5) at 71.9 V at 0 degrees C with variations of only +/- 7.2% over 4 x 4 pixels. Excellent uniformity was also obtained for photon detection efficiencies (PDE) of +/- 6.4%, whilst dark count rates at the single photoelectron (1 p.e.) level amounted to similar or equal to 2 Mcps/pixel, measured at 0 degrees C. As the first step toward using the device in scintillation photon detectors, we fabricated a prototype gamma-ray camera consisting of an MPPC array optically coupled with a scintillator matrix, namely a 4 x 4 array of 3 x 3 x 10 mm(3) crystals. Specifically, we tested the performance with Ce-doped (Lu, Y)(2)(SiO(4))O (Ce:LYSO), Pr-doped Lu(3)Al(5)O(12) (Pr:LuAG) and "surface coated" Pr:LuAG (Pr:LuAG (WES)) matrices whereby the emission peak of Pr:LuAG was shifted from 310 to 420 nm via a wavelength shifter (WLS). Average energy resolutions of 13.83%, 14.70% and 13.96% (FWHM) were obtained for 662 keV gamma-rays, as measured at 0 degrees C with Ce:LYSO, Pr:LuAG and Pr:LuAG (WLS) scintillator matrices, respectively. We confirmed that the effective PDE for Pr:LuAG (WLS) had improved by more than 30% compared to original, non-coated Pr:LuAG matrix. These results suggest that a large-area monolithic MPPC array developed here could be promising for future medical imaging, particularly in positron emission tomography (PET). (C) 2011 Elsevier B.V. All rights reserved.

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  • Erratum: Multi-wavelength observations of the flaring gamma-ray blazar 3C 66A in 2008 october (Astrophysical Journal (2011) 726 (43))

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, D.S. Davis, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S.J. Fegan, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, L.C. Reyes, J. Ripken, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, C. Sgrò, M.S. Shaw, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler, V.A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Beilicke, W. Benbow, M. Böttcher, D. Boltuch, S.M. Bradbury, J.H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, J.L. Christiansen, L. Ciupik, W. Cui, I. De La Calle Perez, R. Dickherber, M. Errando, A. Falcone, J.P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, G.H. Gillanders, S. Godambe, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C.M. Hui, T.B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M.J. Lang, S. Lebohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, P. Moriarty, R. Mukherjee, R.A. Ong, A.N. Otte, D. Pandel, J.S. Perkins, A. Pichel, M. Pohl, J. Quinn, K. Ragan, P.T. Reynolds, E. Roache, H.J. Rose, M. Schroedter, G.H. Sembroski, G.D. Senturk, A.W. Smith, D. Steele, S.P. Swordy, G. Teić, M. Theiling, S. Thibadeau, A. Varlotta, V.V. Vassiliev, S. Vincent, S.P. Wakely, J.E

    Astrophysical Journal   731 ( 1 )  2011.04  [Refereed]

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  • The first fermi multifrequency campaign on BL Lacertae: Characterizing the low-activity state of the eponymous blazar

    A.A. Abdo, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çlik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, C.D. Dermer, F. De Palma, D. Donato, E. Do Couto E Silva, P.S. Drell, R. Dubois, L. Escande, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, S.-H. Lee, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, F.K. Schinzel, C. Sgrò, E.J. Siskind, P.D. Smith, K.V. Sokolovsky, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T. Uehara, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler, A. Berdyugin, M. Boettcher, A. Carramĩana, L. Carrasco, E. De La Fuente, C. Diltz, T. Hovatta, V. Kadenius, Y.Y. Kovalev, A. Lähteenmäki, E. Lindfors, A.P. Marscher, K. Nilsson, D. Pereira, R. Reinthal, P. Roustazadeh, T. Savolainen, A. Sillanpää, L.O. Takalo, M. Tornikoski

    Astrophysical Journal   730 ( 2 )  2011.04  [Refereed]

     View Summary

    We report on observations of BLLacertae during the first 18 months of Fermi LAT science operations and present results from a 48 day multifrequency coordinated campaign from 2008 August 19 to 2008 October 7. The radio to gamma-ray behavior of BLLac is unveiled during a low-activity state thanks to the coordinated observations of radio-band (Metsähovi and VLBA), near-IR/optical (Tuorla, Steward, OAGH, and MDM), and X-ray (RXTE and Swift) observatories. No variability was resolved in gamma rays during the campaign, and the brightness level was 15 times lower than the level of the 1997 EGRET outburst. Moderate and uncorrelated variability has been detected in UV and X-rays. The X-ray spectrum is found to be concave, indicating the transition region between the low- and high-energy components of the spectral energy distribution (SED). VLBA observation detected a synchrotron spectrum self-absorption turnover in the innermost part of the radio jet appearing to be elongated and inhomogeneous, and constrained the average magnetic field there to be less than 3 G. Over the following months, BLLac appeared variable in gamma rays, showing flares (in 2009 April and 2010 January). There is no evidence for the correlation of gamma rays with the optical flux monitored from the ground in 18 months. The SED may be described by a single-zone or a two-zone synchrotron self-Compton (SSC) model, but a hybrid SSC plus external radiation Compton model seems to be preferred based on the observed variability and the fact that it provides a fit closest to equipartition. © 2011. The American Astronomical Society. All rights reserved.

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  • Searching for X-ray counterparts of Fermi Gamma-ray pulsars in Suzaku observations

    Aoki, Y, Enomoto, T, Yatsu, Y, Kawai, N, Nakamori, T, Kataoka, J, Saz Parkinson, P

    Proceedings of the International Astronomical Union   7 ( S279 ) 317 - 318  2011.04

     View Summary

    We report the Suzaku follow-up observations of the Gamma-ray pulsars, 1FGL J0614,13328, J1044.55737, J1741.82101, and J1813.31246, which were discovered by the Fermi Gamma-ray observatory. Analysing Suzaku/XIS data, we detected X-ray counterparts of these pulsars in the Fermi error circle and interpreted their spectra with absorbed power-law functions. These results indicate that the origin of these X-ray sources is non-thermal emission from the pulsars or from Pulsar Wind Nebulae (PWNe) surrounding them. Moreover we found that J1741.82101 exhibits a peculiar profile: spin-down luminosity vs flux ratio between X-and gamma-rays is unusually large compared to usual radio pulsars. © 2012 International Astronomical Union.

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  • Detection of a spectral break in the extra hard component of GRB 090926A

    M. Ackermann, M. Ajello, K. Asano, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R.D. Blandford, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, V. Chaplin, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, B.L. Dingus, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, A. Goldstein, J. Granot, J. Greiner, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, R.M. Kippen, J. Knödlseder, D. Kocevski, C. Kouveliotou, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Llena Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, S. McBreen, J.E. McEnery, S. McGlynn, C. Meegan, J. Mehault, P. Mészáros, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, H. Nakajima, T. Nakamori, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, W.S. Paciesas, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, V. Petrosian, F. Piron, T.A. Porter, R. Preece, J.L. Racusin, S. Rainò, R. Rando, A. Rau, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, L.C. Reyes, J. Ripken, S. Ritz, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, Y. Tanaka, J.B. Thayer, J.G. Thayer, L. Tibaldo, D. Tierney, K. Toma, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, X.F. Wu, R. Yamazaki, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal   729 ( 2 )  2011.03  [Refereed]

     View Summary

    We report on the observation of the bright, long gamma-ray burst, GRB090926A, by the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other gamma-ray bursts, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit. © 2011. The American Astronomical Society. All rights reserved.

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  • THE FIRST FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS (vol 187, pg 460, 2010)

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Oe. Celik, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, S. Cutini, P. R. den Hartog, C. D. Dermer, A. de Angelis, A. de Luca, F. de Palma, S. W. Digel, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, M. Frailis, P. C. C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, C. Gwon, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, M. S. Jackson, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, G. Kanbach, V. M. Kaspi, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, M. L. Kocian, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. G. Lyne, G. M. Madejski, A. Makeev, R. N. Manchester, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, T. Mineo, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, S. M. Ransom, P. S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, B. W. Stappers, J. -L. Starck, E. Striani, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, G. Theureau, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, N. Wang, K. Watters, P. Weltevrede, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   193 ( 1 ) 460 - 494  2011.03  [Refereed]

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  • 27pGS-11 Structure designs of active shields for the ASTRO-H Hard X-ray and Soft Gamma-ray Detector

    Nakajima K, Nakano T, Nakazawa K, Makishima K, Hanabata Y, Fukazawa Y, Yamaoka K, Tajima H, Kataoka J, Takahashi H, Mizuno T, Ohno M, Kokubun M, Takahashi T, Watanabe S, Tashiro M, Terada Y

    Meeting abstracts of the Physical Society of Japan   66 ( 1 ) 122 - 122  2011.03

    CiNii

  • 28aGP-6 High resolution gamma-ray imagers using APD/MPPC

    Kataoka Jun

    Meeting abstracts of the Physical Society of Japan   66 ( 1 ) 36 - 36  2011.03

    CiNii

  • UNRAVELING THE NATURE OF UNIDENTIFIED HIGH GALACTIC LATITUDE FERMI/LAT GAMMA-RAY SOURCES WITH SUZAKU

    K. Maeda, J. Kataoka, T. Nakamori, L. Stawarz, R. Makiya, T. Totani, C. C. Cheung, D. Donato, N. Gehrels, P. Saz Parkinson, Y. Kanai, N. Kawai, Y. Tanaka, R. Sato, T. Takahashi, Y. Takahashi

    ASTROPHYSICAL JOURNAL   729 ( 2 ) 103 - 116  2011.03  [Refereed]

     View Summary

    Here we report on the results of deep X-ray follow-up observations of four unidentified gamma-ray sources detected by the Fermi/LAT instrument at high Galactic latitudes using the X-ray Imaging Spectrometers on board the Suzaku satellite. All of the studied objects were detected with high significance during the first three months of Fermi/LAT operation and subsequently better localized in the first Fermi/LAT catalog (1FGL). For some of them, possible associations with pulsars and active galaxies have subsequently been discussed, and our observations provide an important contribution to this debate. In particular, a bright X-ray point source has been found within the 95% confidence error circle of 1FGL J1231.1-1410. The X-ray spectrum of the discovered Suzaku counterpart of 1FGL J1231.1-1410 is well fitted by a blackbody with an additional power-law component. This supports the recently claimed identification of this source with a millisecond pulsar PSR J1231-1411. For the remaining three Fermi objects, on the other hand, the X-ray observations performed are less conclusive. In the case of 1FGL J1311.7-3429, two bright X-ray point sources were found within the LAT 95% error circle. Even though the X-ray spectral and variability properties for these sources were robustly assessed, their physical nature and relationship with the gamma-ray source remain uncertain. Similarly, we found several weak X-ray sources in the field of 1FGL J1333.2+5056, one coinciding with the high-redshift blazar CLASS J1333+5057. We argue that the available data are consistent with the physical association between these two objects, although the large positional uncertainty of the gamma-ray source hinders a robust identification. Finally, we have detected an X-ray point source in the vicinity of 1FGL J2017.3+0603. This Fermi object was recently suggested to be associated with a newly discovered millisecond radio pulsar PSR J2017+0603, because of the spatial coincidence and the detection of the gamma-ray pulsations in the light curve of 1FGL J2017.3+0603. Interestingly, we have detected the X-ray counterpart of the high-redshift blazar CLASS J2017+0603, located within the error circle of the gamma-ray source, while we were only able to determine an X-ray flux upper limit at the pulsar position. All in all, our studies indicate that while a significant fraction of unidentified high Galactic latitude gamma-ray sources is related to the pulsar and blazar phenomena, associations with other classes of astrophysical objects are still valid options.

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  • Radio and γ-ray constraints on the emission geometry and birthplace of PSR j2043+2740

    A. Noutsos, A.A. Abdo, M. Ackermann, M. Ajello, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, G. Busetto, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, S. Chaty, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, S. Colafrancesco, S. Cutini, C.D. Dermer, F. De Palma, P.S. Drell, D. Dumora, C.M. Ea, C. Favuzzi, E.C. Ferrara, W.B. Focke, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, G. Godfrey, P. Grandi, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, A.K. Harding, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, S.-H. Lee, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, P.L. Nolan, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Persic, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, R.W. Romani, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, G. Theureau, D.J. Thompson, S.E. Thorsett, O. Tibolla, D.F. Torres, A. Tramacere, T.L. Usher, J. Vandenbroucke, G. Vianello, N. Vilchez, M. Villata, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, K. Watters, P. Weltevrede, B.L. Winer, K.S. Wood, M. Ziegler

    Astrophysical Journal   728 ( 2 )  2011.02  [Refereed]

     View Summary

    We report on the first year of Fermi γ-ray observations of pulsed high-energy emission from the old PSR J2043 + 2740. The study of the γ-ray efficiency of such old pulsars gives us an insight into the evolution of pulsars' ability to emit in γ rays as they age. The y-ray light curve of this pulsar above 0.1 GeV is clearly defined by two sharp peaks, 0.353 ± 0.035 periods apart. We have combined the γ-ray profile characteristics of PSR J2043 + 2740 with the geometrical properties of the pulsar's radio emission, derived from radio-polarization data, and constrained the pulsar-beam geometry in the framework of a two-pole caustic (TPC) and an outer gap (OG) model. The ranges of magnetic inclination and viewing angle were determined to be {α, ζ} ∼ {52°-57°, 61°-68°} for the TPC model, and {α, ζ} ∼ {62°-73°, 74°-81°} and {α, ζ,} ∼ {72°-83°, 60°-75°} for the OG model. Based on this geometry, we assess possible birth locations for this pulsar and derive a likely proper motion, sufficiently high to be measurable with VLBI. At a characteristic age of 1.2 Myr, PSR J2043 + 2740 is the third oldest of all discovered, non-recycled, γ-ray pulsars: it is twice as old as the next oldest, PSR J0357 + 32, and younger only than the recently discovered PSR J1836 + 5925 and PSR J2055 + 25, both of which are at least five and ten times less energetic, respectively. © 2011. The American Astronomical Society.

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  • Gamma-ray flares from the Crab Nebula

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, J.M. Casandjian, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. Costamante, S. Cutini, F. D'Ammando, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, M. Hayashida, E. Hays, D. Horan, R. Itoh, G. Jóhannesson, A.S. Johnson, T.J. Johnson, D. Khangulyan, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, J.F. Ormes, M. Ozaki, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, R.W. Romani, H.F.-W. Sadrozinski, D. Sanchez, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, P. Wang, K.S. Wood, Z. Yang, M. Ziegler

    Science   331 ( 6018 ) 739 - 742  2011.02  [Refereed]

     View Summary

    A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (1015 electron volts) electrons in a region smaller than 1.4 × 10-2 parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory.

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  • Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C.D. Dermer, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, L. Guillemot, S. Guiriec, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pavlidou, T.J. Pearson, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, J.L. Richards, J. Ripken, S. Ritz, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, L. Stawarz, M. Stevenson, M.S. Strickm, K.V. Sokolovsky, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, A.E. Wehrle, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, J.A. Zensus, M. Ziegler, J. Aleksić, L.A. Antonelli, P. Antoranz, M. Backes, J.A. Barrio, J.B. González, W. Bednarek, A. Berdyugin, K. Berger, E. Bernardini, A. Biland, O. Blanch, R.K. Bock, A. Boller, G. Bonnoli, P. Bordas, D.B. Tridon, V. Bosch-Ramon, D. Bose, I. Braun, T. Bretz, M. Camara, E. Carmona, A. Carosi, P. Colin, E. Colombo, J.L. Contreras, J. Cortina, S. Covino, F. Dazzi, A. De Angelis, E. De Cea Del Pozo, B. De Lotto, M. De Maria, F. De Sabata, C. Delgado Mendez, A. Diago Ortega, M. Doert, A. Domínguez, D.D. Prester, D. Dorner, M. Doro, D. Elsaesser, D. Ferenc, M.V. Fonseca, L. Font, R.J.G. López, M. Garczarczyk, M. Gaug, G. Giavitto, N. Godinovi, D. Hadasch, A. Herrero, D. Hildebrand, D. Höhne-Mönch, J. Hose, D. Hrupec, T. Jogler, S. Klepser, T. Krähenbühl, D

    Astrophysical Journal   727 ( 2 )  2011.02  [Refereed]

     View Summary

    We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society.

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  • Searching for the most distant blazars with the Fermi Gamma-ray Space Telescope

    Yoshiyuki Inoue, Susumu Inoue, Masakazu A. R. Kobayashi, Tomonori Totani, Jun Kataoka, Rie Sato

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   411 ( 1 ) 464 - 468  2011.02  [Refereed]

     View Summary

    We investigate the prospects for discovering blazars at very high redshifts (z greater than or similar to 3-6) with the Fermi Gamma-ray Space Telescope (hereinafter Fermi), employing a model for the evolving gamma-ray luminosity function (GLF) of the blazar population. Our previous GLF model is used as a basis, which features luminosity-dependent density evolution implied from X-ray data on active galactic nuclei as well as the blazar sequence paradigm for their spectral energy distribution, and which is consistent with the Energetic Gamma-Ray Experiment Telescope and the current Fermi observations of blazars. Here, we augment the high-redshift evolution of this model by utilizing the luminosity function of quasars from the Sloan Digital Sky Survey, which is well-constrained up to z similar to 5. We find that the Fermi may discover a few blazars up to z similar to 6 in the entire sky during its 5-yr survey. We further discuss how such high-redshift blazar candidates may be efficiently selected in the future Fermi data.

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  • Development of the small satellite “Tsubame”

    Toizumi, T, Enomoto, Yatsu, Y, Nakamori, T, Kawai, N, Ishizuka, K, Morishita, H, Akiyama, K, Kisa, N, Inagawa, S, Kawakubo, M, Nishida, J, Mizunuma, S, Matsunaga, S, Kataoka, J

    Physica E   43 ( 3 ) 685 - 688  2011.01  [Refereed]

     View Summary

    Tsubame is a university-built small satellite mission to measure polarization of hard X-ray photons (30200 keV) from gamma-ray bursts (GRB) using azimuthal angle anisotropy of Compton-scattered photons. Polarimetry in the hard X-ray and soft gamma-ray band should play a crucial role in understanding of high energy emission mechanisms, the distribution of magnetic fields and radiation fields of gamma-ray bursts. Tsubame has two instruments: the Wide-field Bust Monitor (WBM) and the Hard X-ray Compton Polarimeter (HXCP). The WBM detects a burst and determines on board the direction of the burst occurrence with an accuracy of 10°. The spacecraft is then slewed to point the GRB within 15 s from the WBM trigger using the Control Moment Gyro (CMG), a high speed attitude control device. HXCP will measure the polarized X-ray photons from the GRB while the spacecraft spins slowly around the bore sight. In this paper, we present an overview of the Tsubame mission, the results of a test experiment for HXCP using a polarized hard X-ray beam, and its comparison with a Monte Carlo simulation. © 2010 ElsevierB.V. All rights reserved.

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  • Constraints on the cosmic-ray density gradient beyond the solar circle from fermi γ-ray observations of the third galactic quadrant

    M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, F. De Palma, S.W. Digel, P.S. Drell, R. Dubois, C. Favuzzi, E.C. Ferrara, W.B. Focke, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, M. Hayashida, R.E. Hughes, R. Itoh, G. J́ohannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Kn̈odlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M.L. Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, P. Martin, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Raiǹo, R. Rando, M. Razzano, A. Reimer, O. Reimer, J. Ripken, T. Sada, H.F.-W. Sadrozinski, C. Sgr̀o, E.J. Siskind, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.E. Vladimirov, A.P. Waite, P. Wang, K.S. Wood, Z. Yang, M. Ziegler

    Astrophysical Journal   726 ( 2 )  2011.01  [Refereed]

     View Summary

    We report an analysis of the interstellar γ-ray emission in the third Galactic quadrant measured by the Fermi Large Area Telescope. The window encompassing the Galactic plane from longitude 210° to 250° has kinematically well-defined segments of the Local and the Perseus arms, suitable to study the cosmic-ray (CR) densities across the outer Galaxy. We measure no large gradient with Galactocentric distance of the γ-ray emissivities per interstellar H atom over the regions sampled in this study. The gradient depends, however, on the optical depth correction applied to derive the H i column densities. No significant variations are found in the interstellar spectra in the outer Galaxy, indicating similar shapes of the CR spectrum up to the Perseus arm for particles with GeV to tens of GeV energies. The emissivity as a function of Galactocentric radius does not show a large enhancement in the spiral arms with respect to the interarm region. The measured emissivity gradient is flatter than expectations based on a CR propagation model using the radial distribution of supernova remnants and uniform diffusion properties. In this context, observations require a larger halo size and/or a flatter CR source distribution than usually assumed. The molecular mass calibrating ratio, XCO = N(H2)/WCO, is found to be (2.08±0.11)×1020 cm -2(K km s-1)-1 in the Local arm clouds and is not significantly sensitive to the choice of Hi spin temperature. No significant variations are found for clouds in the interarm region. © 2011 The American Astronomical Society. All rights reserved.

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  • Time over Threshold Based Digital Animal PET (TODPET)

    K. Shimazoe, Y. Wang, H. Takahashi, K. Kamada, M. Yoshino, J. Kataoka, Y. Yamaya, T. Yanagida, A. Yoshikawa, K. Kumagai

    2011 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC)     3267 - 3271  2011  [Refereed]

     View Summary

    We have developed Time over Threshold (ToT) based Pr:LuAG-APD PET (TODPET) tomograph with a mixed signal front-end. The tomograph consists of 8 block detectors, each of which is composed of a 12 x 12 array of 2 x 2 x 10mm(3) Pr:LuAG crystals individually coupled with 12 x 12 UV-enhanced APD arrays. The APDs are individually read out with a custom-designed Time over Threshold ASIC and FPGA readout system. Developed PET tomograph has the energy resolution of 10% and the time resolution of 4.2ns. The 1.76mm spatial resolution (FWHM) is achieved for the first result.

  • Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

    A. Abramowski, F. Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, A. Barnacka, U. Barres De Almeida, A. R. Bazer-Bachi, Y. Becherini, J. Becker, B. Behera, K. Bernlöhr, A. Bochow, C. Boisson, J. Bolmont, P. Bordas, V. Borrel, J. Brucker, F. Brun, P. Brun, T. Bulik, I. Büsching, S. Casanova, M. Cerruti, P. M. Chadwick, A. Charbonnier, R. C.G. Chaves, A. Cheesebrough, L. M. Chounet, A. C. Clapson, G. Coignet, J. Conrad, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Ataï, W. Domainko, L. O. Drury, F. Dubois, G. Dubus, J. Dyks, M. Dyrda, K. Egberts, P. Eger, P. Espigat, L. Fallon, C. Farnier, S. Fegan, F. Feinstein, M. V. Fernandes, A. Fiasson, G. Fontaine, A. Förster, M. Füßling, S. Gabici, Y. A. Gallant, H. Gast, L. Gérard, D. Gerbig, B. Giebels, J. F. Glicenstein, B. Glück, P. Goret, D. Göring, J. D. Hague, D. Hampf, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, P. Hofverberg, D. Horns, A. Jacholkowska, O. C. De Jager, C. Jahn, M. Jamrozy, I. Jung, M. A. Kastendieck, K. Katarzyński, U. Katz, S. Kaufmann, D. Keogh, M. Kerschhaggl, D. Khangulyan, B. Khélifi, D. Klochkov, W. Kluåniak, T. Kneiske, Nu Komin, K. Kosack, R. Kossakowski, H. Laffon, G. Lamanna

    Astronomy and Astrophysics   533  2011

     View Summary

    The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E > 100 GeV) spectrum measured with H.E.S.S. © 2011 ESO.

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  • Experimental demonstration of single-photon detection using InGaAs avalanche photodiode operated in sub-Geiger mode

    Kenji Tsujino, Yoshito Miyamoto, Jun Kataoka, Akihisa Tomita

    AIP Conference Proceedings   1363   351 - 354  2011

     View Summary

    The avalanche photodiode (APD) is a promising device for single-photon detection. In this study, we operated an InGaAs APD in the sub-Geiger mode. In this mode, a gate pulse is not needed; therefore, we can detect photons with asynchronous timing. The detection efficiency and the dark count rate were 2.2% and 7900 counts per second (cps), respectively. © 2011 American Institute of Physics.

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  • Scintillation properties of transparent Lu3Al5O12 (LuAG) ceramics doped with different concentrations of Pr3+

    Takayuki Yanagida, Akihiro Fukabori, Yutaka Fujimoto, Akio Ikesue, Kei Kamada, Jun Kataoka, Yuui Yokota, Akira Yoshikawa, Valery Chani

    PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 1   8 ( 1 ) 140 - 143  2011  [Refereed]

     View Summary

    Transparent ceramics of Pr-doped (0.2 mol%, 0.6 mol%, 1 mol%, and 2 mol%) Lu3Al5O12 (LuAG) scintillators produced by the sintering method are discussed. These materials were cut to the specimens with physical dimensions of 5 x 5 x 2 mm(3). Similar size specimens were also prepared from Czochralski grown Pr:LuAG single crystals to compare scintillation properties. Their transmittance and radio luminescence spectra were evaluated. All specimens were highly transparent in wavelength range above 300 nm, and intense Pr3+ 5d-4f emission was detected around 310 and 370 nm under excitation with X-ray. Under Cs-137 gamma-ray is irradiation, 2 keV photoabsorption peaks were also clearly observed in each sample. The Pr 0.6 mol% doped LuAG ceramics demonstrated highest light yield achievable among the ceramics, and it was half of that observed in the single crystals. Under pulse X-ray excitation, the decay time constants became faster when Pr concentration increased, and. the fastest decay (similar to 5.7 ns time constant) was noticed in the 2 mol% doped ceramic. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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  • Fermi-LAT search for pulsar wind nebulae around gamma-ray pulsars

    M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, K. Hayashi, E. Hays, G. Hobbs, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, A. Noutsos, E. Nuss, T. Ohsugi, A. Okumura, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, R.W. Romani, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, J. Vandenbroucke, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, P. Weltevrede, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal   726 ( 1 )  2011.01  [Refereed]

     View Summary

    The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three PWNe: the Crab Nebula, Vela-X, and the PWN inside MSH 15-52. In the meantime, the list of LAT detected pulsars increased steadily. These pulsars are characterized by high energy loss rates (Ė) from ∼3 × 10 33 erg s-1 to 5 × 1038 erg s-1 and are therefore likely to power a PWN. This paper summarizes the search for PWNe in the off-pulse windows of 54 LAT-detected pulsars using 16 months of survey observations. Ten sources show significant emission, seven of these likely being of magnetospheric origin. The detection of significant emission in the off-pulse interval offers new constraints on the γ-ray emitting regions in pulsar magnetospheres. The three other sources with significant emission are the Crab Nebula, Vela-X, and a new PWN candidate associated with the LAT pulsar PSR J1023-5746, coincident with the TeV source HESS J1023-575. We further explore the association between the HESS and the Fermi source by modeling its spectral energy distribution. Flux upper limits derived for the 44 remaining sources are used to provide new constraints on famous PWNe that have been detected at keV and/or TeV energies. © 2011. The American Astronomical Society. All rights reserved. Printedin the U.S.A.

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  • Multi-wavelength observations of the flaring gamma-ray blazar 3C 66A in 2008 October

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, D.S. Davis, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S.J. Fegan, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, L.C. Reyes, J. Ripken, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, C. Sgrò, M.S. Shaw, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler, V.A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Beilicke, W. Benbow, M. Böttcher, D. Boltuch, S.M. Bradbury, J.H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, J.L. Christiansen, L. Ciupik, W. Cui, I. De La Calle Perez, R. Dickherber, M. Errando, A. Falcone, J.P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, G.H. Gillanders, S. Godambe, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C.M. Hui, T.B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M.J. Lang, S. LeBohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, P. Moriarty, R. Mukherjee, R.A. Ong, A.N. Otte, D. Pandel, J.S. Perkins, A. Pichel, M. Pohl, J. Quinn, K. Ragan, P.T. Reynolds, E. Roache, H.J. Rose, M. Schroedter, G.H. Sembroski, G.D. Senturk, A.W. Smith, D. Steele, S.P. Swordy, G. Tešić, M. Theiling, S. Thibadeau, A. Varlotta, V.V. Vassiliev, S. Vincent, S.P. Wakely, J

    Astrophysical Journal   726 ( 1 )  2011.01  [Refereed]

     View Summary

    The BL Lacertae object 3C 66A was detected in a flaring state by the Fe r m i Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra provided radio to X-ray coverage. The available light curves show variability and, in particular, correlated flares are observed in the optical and Fermi-LAT gamma-ray band. The resulting spectral energy distribution can be well fitted using standard leptonic models with and without an external radiation field for inverse Compton scattering. It is found, however, that only the model with an external radiation field can accommodate the intra-night variability observed at optical wavelengths. © 2011. The American Astronomical Society.

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  • Search for gamma-ray emission from magnetars with the Fermi large area telescope

    A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, C. Cecchi, Ö Çelik, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Conrad, P. R. Den Hartog, C. D. Dermer, A. De Angelis, F. De Palma, R. Dib, M. Dormody, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, T. Enoto, C. Favuzzi, M. Frailis, P. Fusco, F. Gargano, N. Gehrels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, E. Hays, G. L. Israel, G. Jóhannesson, A. S. Johnson, V. M. Kaspi, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, P. L. Nolan, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pepe

    Astrophysical Journal Letters   725 ( 1 PART 2 )  2010.12

     View Summary

    We report on the search for 0.1-10GeV emission from magnetars in 17months of Fermi LargeAreaTelescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi energy range are estimated between ∼10-12 and 10-10 erg s-1 cm-2, depending on the source.We also searched for gamma-ray pulsations and possible outbursts, also with no significant detection. The upper limits derived support the presence of a cutoff at an energy below a few MeV in the persistent emission of magnetars. They also show the likely need for a revision of current models of outer-gap emission from stronglymagnetized pulsars, which, in some realizations, predict detectableGeV emission frommagnetars at flux levels exceeding the upper limits identified here using the Fermi-LAT observations. © 2010. The American Astronomical Society. All rights reserved.

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  • A thermal-neutron detector with a phoswich system of LiCaAlF<inf>6</inf>and BGO crystal scintillators onboard PoGOLite

    H. Takahashi, M. Yonetani, M. Matsuoka, T. Mizuno, Y. Fukazawa, T. Yanagida, Y. Fujimoto, Y. Yokota, A. Yoshikawa, N. Kawaguchi, S. Ishizu, K. Fukuda, T. Suyama, K. Watanabe, H. Tajima, Y. Kanai, N. Kawai, J. Kataoka, J. Katsuta, T. Takahashi, S. Gunji, M. Axelsson, M. Jackson, M. Kiss, W. Klamra, M. Kole, S. Larsson, P. Mallol, M. Pearce, F. Ryde, S. Rydstrom, G. Olofsson, H. G. Floren, T. Kamae, G. Madejski, G. Varner

    IEEE Nuclear Science Symposium Conference Record     32 - 37  2010.12

     View Summary

    To measure the flux of atmospheric neutrons and study the neutron contribution to the background of the main detector of the PoGOLite (Polarized Gamma-ray Observer) balloon-borne experiment, a thermal-neutron detector with a phoswich system of LiCaAlF6(Eu) and BGO crystal scintillators is developed. The performance to separate thermal-neutron events from those of gamma-rays and charged particles is validated with252Cf on ground. The detector is attached to the PoGOLite instrument and is launched in 2011 from the Esrange facility in the North of Sweden. Although the emission wavelength of the LiCaAlF6(Ce) is 300 nm and overlaps with the absorption wavelength of the BGO, the phoswich capability of the LiCaAlF6(Ce) with the BGO is also confirmed with installing a waveform shifter. © 2010 IEEE.

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  • Small Satellite "TSUBAME" for Polarimetry of Gamma-ray Burst

    Enomoto, T, Kawakami, K, Tokoyoda, K, Toizumi, T, Yatsu, Y, Kawai, N, Matsunaga, S, Nakamori, T, Kataoka, J, Kubo, S

    Proc. of 4th MAXI Workshop     65 - 4pp  2010.12

  • A NOVEL APPROACH IN CONSTRAINING ELECTRON SPECTRA IN BLAZAR JETS: THE CASE OF Markarian 421

    Masayoshi Ushio, Lukasz Stawarz, Tadayuki Takahashi, David Paneque, Grzegorz Madejski, Masaaki Hayashida, Jun Kataoka, Yasuyuki T. Tanaka, Takaaki Tanaka, Michal Ostrowski

    ASTROPHYSICAL JOURNAL   724 ( 2 ) 1509 - 1516  2010.12  [Refereed]

     View Summary

    We report results from the observations of the well-studied TeV blazar Mrk 421 with the Swift and the Suzaku satellites in 2008 December. During the observation, Mrk 421 was found in a relatively low activity state, with the corresponding 2-10 keV flux of 3 x 10(-10) erg s(-1) cm(-2). For the purpose of robustly constraining the UV-to-X-ray emission continuum we selected only the data corresponding to truly simultaneous time intervals between Swift and Suzaku, allowing us to obtain a good-quality, broadband spectrum despite a modest length (0.6 ks) exposure. We analyzed the spectrum with the parametric forward-fitting SYNCHROTRON model implemented in XSPEC assuming two different representations of the underlying electron energy distribution, both well motivated by the current particle acceleration models: a power-law distribution above the minimum energy gamma(min) with an exponential cutoff at the maximum energy gamma(max), and a modified ultra-relativistic Maxwellian with an equilibrium energy gamma(eq). We found that the latter implies unlikely physical conditions within the blazar zone of Mrk 421. On the other hand, the exponentially moderated power-law electron distribution gives two possible sets of the model parameters: (1) flat spectrum dN'(e)/d gamma proportional to gamma(-1.91) with low minimum electron energy gamma(min) &lt; 10(3), and (2) steep spectrum proportional to gamma(-2.77) with high minimum electron energy gamma(min) similar or equal to 2 x 10(4). We discuss different interpretations of both possibilities in the context of a diffusive acceleration of electrons at relativistic, sub- or superluminal shocks. We also comment on exactly how the gamma-ray data can be used to discriminate between the different proposed scenarios.

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  • A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

    A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, E. Charles, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, M. E. Decesar, C. D. Dermer, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Favuzzi, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A. K. Harding, E. Hays, P. Jean, G. Jóhannesson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, B. Pancrazi

    Astronomy and Astrophysics   524 ( 3 )  2010.11

     View Summary

    Context. Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. The observation of this emission provides a powerful tool to assess the millisecond pulsar population of a cluster, is essential for understanding the importance of binary systems for the evolution of globular clusters, and provides complementary insights into magnetospheric emission processes. Aims. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. Methods. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Results. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices (0.7 < Γ <1.4) and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices (1.0 < Γ < 1.7), however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. Conclusions. The observation of high-energy gamma-ray emission from globular clusters thus provides a reliable independent method to assess their millisecond pulsar populations. © ESO, 2010. © 2010 ESO.

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  • Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV

    M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, F. Belli, B. Berenji, R.D. Blandford, E.D. Bloom, J.R. Bogart, E. Bonamente, A.W. Borgland, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, G. Busetto, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, P. Carlson, S. Carrigan, J.M. Casandjian, M. Ceccanti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, R. Corbet, M. Deklotz, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, G. Di Bernardo, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Fabiani, C. Favuzzi, S.J. Fegan, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, D. Grasso, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, M. Minuti, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, V. Petrosian, M. Pinchera, F. Piron, T.A. Porter, S. Profumo, S. Rainò, R. Rando, E. Rapposelli, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, L.S. Rochester, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, N. Saggini, D. Sanchez, A. Sander, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, Ł. Stawarz, T.E. Stephens, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, M. Turri, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Physical Review D - Particles, Fields, Gravitation and Cosmology   82 ( 9 )  2010.11  [Refereed]

     View Summary

    We present the results of our analysis of cosmic-ray electrons using about 8×106 electron candidates detected in the first 12 months on-orbit by the Fermi Large Area Telescope. This work extends our previously published cosmic-ray electron spectrum down to 7 GeV, giving a spectral range of approximately 2.5 decades up to 1 TeV. We describe in detail the analysis and its validation using beam-test and on-orbit data. In addition, we describe the spectrum measured via a subset of events selected for the best energy resolution as a cross-check on the measurement using the full event sample. Our electron spectrum can be described with a power law E-3.08±0.05 with no prominent spectral features within systematic uncertainties. Within the limits of our uncertainties, we can accommodate a slight spectral hardening at around 100 GeV and a slight softening above 500 GeV. ©2010 The American Physical Society.

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  • Searches for cosmic-ray electron anisotropies with the Fermi Large Area Telescope

    M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, G. Di Bernardo, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, S.J. Fegan, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, D. Grasso, I.A. Grenier, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, A.K. Harding, K. Hayashi, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Profumo, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, M. Roth, H.F.-W. Sadrozinski, A. Sander, T.L. Schalk, C. Sgrò, J. Siegal-Gaskins, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, G. Zaharijas, M. Ziegler

    Physical Review D - Particles, Fields, Gravitation and Cosmology   82 ( 9 )  2010.11  [Refereed]

     View Summary

    The Large Area Telescope on board the Fermi satellite (Fermi LAT) detected more than 1.6×106 cosmic-ray electrons/positrons with energies above 60 GeV during its first year of operation. The arrival directions of these events were searched for anisotropies of angular scale extending from 10°up to 90°, and of minimum energy extending from 60 GeV up to 480 GeV. Two independent techniques were used to search for anisotropies, both resulting in null results. Upper limits on the degree of the anisotropy were set that depended on the analyzed energy range and on the anisotropy's angular scale. The upper limits for a dipole anisotropy ranged from 0.5% to 10%.©2010 The American Physical Society.

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  • Detection of the Small Magellanic Cloud in gamma-rays with Fermi /LAT

    A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, Ö Çelik, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S. J. Fegan, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, A. K. Harding, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, P. Jean, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, A. Makeev, P. Martin, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori

    Astronomy and Astrophysics   523 ( 3 )  2010.11

     View Summary

    Context. The flux of gamma rays with energies greater than 100 MeV is dominated by diffuse emission coming from cosmic-rays (CRs) illuminating the interstellar medium (ISM) of our Galaxy through the processes of Bremsstrahlung, pion production and decay, and inverse-Compton scattering. The study of this diffuse emission provides insight into the origin and transport of cosmic rays. Aims.We searched for gamma-ray emission from the Small Magellanic Cloud (SMC) in order to derive constraints on the cosmic-ray population and transport in an external system with properties different from the Milky Way. Methods.We analysed the first 17 months of continuous all-sky observations by the Large Area Telescope (LAT) of the Fermi mission to determine the spatial distribution, flux and spectrum of the gamma-ray emission from the SMC. We also used past radio synchrotron observations of the SMC to study the population of CR electrons specifically. Results.We obtained the first detection of the SMC in high-energy gamma rays, with an integrated >100MeV flux of (3.7±0.7)×10-8 ph cm-2 s-1, with additional systematic uncertainty of ≤16%. The emission is steady and from an extended source ∼3. in size. It is not clearly correlated with the distribution of massive stars or neutral gas, nor with known pulsars or supernova remnants, but a certain correlation with supergiant shells is observed. Conclusions.The observed flux implies an upper limit on the average CR nuclei density in the SMC of ∼15% of the value measured locally in the Milky Way. The population of high-energy pulsars of the SMC may account for a substantial fraction of the gamma-ray flux, which would make the inferred CR nuclei density even lower. The average density of CR electrons derived from radio synchrotron observations is consistent with the same reduction factor but the uncertainties are large. From our current knowledge of the SMC, such a low CR density does not seem to be due to a lower rate of CR injection and rather indicates a smaller CR confinement volume characteristic size. © 2010 ESO.

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  • Fermi Large Area Telescope observations of Local Group galaxies: Detection of M 31 and search for M 33

    A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, A. Cannon, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S. J. Fegan, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, K. Hayashi, M. Hayashida, E. Hays, S. E. Healey, P. Jean, G. Jóhannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, P. Martin, M. N. Mazziotta, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte

    Astronomy and Astrophysics   523 ( 1 )  2010.11

     View Summary

    Context. Cosmic rays (CRs) can be studied through the galaxy-wide gamma-ray emission that they generate when propagating in the interstellar medium. The comparison of the diffuse signals from different systems may inform us about the key parameters in CR acceleration and transport. Aims. We aim to determine and compare the properties of the cosmic-ray-induced gamma-ray emission of several Local Group galaxies. Methods. We use 2 years of nearly continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to search for gamma-ray emission from M 31 and M 33. We compare the results with those for the Large Magellanic Cloud, the Small Magellanic Cloud, the Milky Way, and the starburst galaxies M 82 and NGC 253. Results. We detect a gamma-ray signal at 5σ significance in the energy range 200 MeV-20 GeV that is consistent with originating from M 31. The integral photon flux above 100 MeV amounts to (9.1 ± 1.9stat ± 1.0) × 10-9 ph cm-2. We find no evidence for emission from M 33 and derive an upper limit on the photon flux >100 MeV of 5.1 × 10-9 ph cm-2-1 (2σ). Comparing these results to the properties of other Local Group galaxies, we find indications of a correlation between star formation rate and gamma-ray luminosity that also holds for the starburst galaxies. Conclusions. The gamma-ray luminosity of M 31 is about half that of the Milky Way, which implies that the ratio between the average CR densities in M 31 and the Milky Way amounts to ξ = 0.35 ± 0.25. The observed correlation between gamma-ray luminosity and star formation rate suggests that the flux of M 33 is not far below the current upper limit from the LAT observations. © 2010 ESO.

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  • Fermi Large Area Telescope constraints on the gamma-ray opacity of the universe

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, A.W. Chen, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, L. Costamante, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, B.L. Dingus, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, S.J. Fegan, J. Finke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, R.C. Gilmore, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, J. Granot, J. Greiner, I.A. Grenier, J.E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, D. Kocevski, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, J. Mehault, P. Mészáros, P.F. Michelson, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, J.R. Primack, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L.C. Reyes, J. Ripken, S. Ritz, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, T.L. Schalk, C. Sgrò, M.S. Shaw, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, R. Yamazaki, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   723 ( 2 ) 1082 - 1096  2010.11  [Refereed]

     View Summary

    The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ∼10 GeV during propagation from sources at cosmological distances. This results in a redshift-and energy-dependent attenuation of the γ-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of γ-ray blazars with redshift up to z ∼ 3, and GRBs with redshift up to z ∼ 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of γ-ray flux attenuation by the EBL. We place upper limits on the?-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. can be ruled out with high confidence. © 2010. The American Astronomical Society.

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  • Fermi large area telescope observation of a gamma-ray source at the position of eta carinae

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto e Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, S.J. Fegan, E.C. Ferrara, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, A.B. Hill, D. Horan, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagir, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M. Livingstone, M. Llena Garde, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, J. Mehault, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, A.Y. Rodriguez, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   723 ( 1 ) 649 - 657  2010.11  [Refereed]

     View Summary

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope detected a γ -ray source that is spatially consistent with the location of Eta Carinae. This source has been persistently bright since the beginning of the LAT survey observations (from 2008 August to 2009 July, the time interval considered here). The γ -ray signal is detected significantly throughout the LAT energy band (i.e., up to ∼100 GeV). The 0.1-100 GeV energy spectrum is well represented by a combination of a cutoff power-law model (<10 GeV) and a hard power-law component (>10 GeV). The total flux (>100 MeV) is 3.7+0.30.1 ×107 photons s1 cm2, with additional systematic uncertainties of 10%, and consistent with the average flux measured by AGILE. The light curve obtained by Fermi is consistent with steady emission. Our observations do not confirm the presence of a γ -ray flare in 2008 October, as reported by Tavani et al., although we cannot exclude that a flare lasting only a few hours escaped detection by the Fermi LAT.We also do not find any evidence for γ -ray variability that correlates with the large X-ray variability of Eta Carinae observed during 2008 December and 2009 January. We are thus not able to establish an unambiguous identification of the LAT source with Eta Carinae. © 2010. The American Astronomical Society.

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  • Fermi-LAT study of Gamma-ray emission in the direction of supernova remnant W49B

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, F. De Palma, S.W. Digel, E. Do couto E Silva, P.S. Drell, D. Dumora, C. Favuzzi, S. Funk, P. Fusco, F. Gargano, N. Gehrels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Katsuta, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, M. Roth, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   722 ( 2 ) 1303 - 1311  2010.10  [Refereed]

     View Summary

    We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38s is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5 × 1036 (D/8 kpc)2 erg s -1 in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the supernova remnant (SNR) shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral π mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, Ue,p > 104 eVcm-3, for either gamma-ray production mechanism. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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  • Gamma-ray light curves and variability of bright fermi-detected blazars

    A.A. Abdo, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, S.E. Healey, D. Horan, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, E. Massaro, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, M. Mueller, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, J.D. Scargle, C. Sgrò, M.S. Shaw, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   722 ( 1 ) 520 - 542  2010.10  [Refereed]

     View Summary

    This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4-2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis. For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares. More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range. Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects. Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks. Variable sources of the sample have weekly and 3-4 day bin light curves that can be described by 1/fα PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)-measured for a few blazars showing strong activity-complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism. The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 1.5 and 1.7, respectively. The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days. Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars. © 2010. The American Astronomical Society. All rights reserved.

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  • FERMI Large Area Telescope and multi-wavelength observations of the flaring activity of PKS 1510-089 between 2008 september and 2009 june

    A.A. Abdo, M. Ackermann, I. Agudo, M. Ajello, A. Allafort, H.D. Aller, M.f. Aller, E. Antolini, A.A. Arkharov, M. Axelsson, U. Bach, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, A. Berdyugin, B. Berenji, R.D. Blandford, D.A. Blinov, E.D. Bloom, M. Boettcher, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, C.S. Buemi, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, D. Carosati, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, W.P. Chen, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Corbel, L. Costamante, C.D. Dermer, A. De Angelis, F. De Palma, D. Donato, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, E. Forné, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, M.A. Gurwell, C. Gusbar, J.L. Gómez, D. Hadasch, V.A. Hagen-Thorn, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, G. Kimeridze, J. Knödlseder, T.S. Konstantinova, E.N. Kopatskaya, E. Koptelova, Y.Y. Kovalev, O.M. Kurtanidze, M. Kuss, A. Lahteenmaki, J. Lande, V.M. Larionov, E.G. Larionova, L.V. Larionova, S. Larsson, L. Latronico, S.-H. Lee, P. Leto, M.L. Lister, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, E. Massaro, M.N. Mazziotta, W. McConville, J.E. McEnery, I.M. McHardy, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, D.A. Morozova, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, M.G. Nikolashvili, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pasanen, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, A.B. Pushkarev, S. Rainò, C.M. Raiteri, R. Rando, M. Razzano, A. Reimer, O. Reimer, R. Reinthal, J. Ripken, S. Ritz, M. Roca-Sogorb, A.Y. Rodriguez, M. Roth, P. Roustazadeh, F. Ryde, H.F.-W. Sadrozinski, A. Sander, J.D. Scargle, C. Sgrò, L.A. Sigua, P.D. Smith, K. Sokolovsky, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, L.O. Takalo, T. Tanaka, B. Taylor, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, M. Tornikoski, D.F. Torres, G. Tosti, A. Tramacere, C. Trigilio, I.S. Troitsky, G. Umana, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   721 ( 2 ) 1425 - 1447  2010.10  [Refereed]

     View Summary

    We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and γ -ray bands, on timescales down to 6-12 hr. The brightest γ -ray isotropic luminosity, recorded on 2009 March 26, was ≃ 2 × 1048 erg s-1. The spectrum in the Fermi Large Area Telescope energy range shows a mild curvature described well by a log-parabolic law, and can be understood as due to the Klein-Nishina effect. The γ -ray flux has a complex correlation with the other wavelengths. There is no correlation at all with the X-ray band, a weak correlation with the UV, and a significant correlation with the optical flux. The γ -ray flux seems to lead the optical one by about 13 days. From the UV photometry, we estimated a black hole mass of ≃ 5.4 × 108M⊙ and an accretion rate of ≃ 0.5M⊙ yr-1. Although the power in the thermal and non-thermal outputs is smaller compared to the very luminous and distant FSRQs, PKS 1510-089 exhibits a quite large Compton dominance and a prominent big blue bump (BBB) as observed in the most powerful γ -ray quasars. The BBB was still prominent during the historical maximum optical state in 2009 May, but the optical/UV spectral index was softer than in the quiescent state. This seems to indicate that the BBB was not completely dominated by the synchrotron emission during the highest optical state. We model the broadband spectrum assuming a leptonic scenario in which the inverse Compton emission is dominated by the scattering of soft photons produced externally to the jet. The resulting model-dependent jet energetic content is compatible with a scenario in which the jet is powered by the accretion disk, with a total efficiency within the Kerr black hole limit. © 2010. The American Astronomical Society. All rights reserved.

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  • FERMI GAMMA-RAY SPACE TELESCOPE OBSERVATIONS OF GAMMA-RAY OUTBURSTS FROM 3C 454.3 IN 2009 DECEMBER AND 2010 APRIL

    Ackermann M, Ajello M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Blandford R. D, Bonamente E, Borgland A. W, Bregeon J, Brigida M, Bruel P, Buehler R, Burnett T. H, Buson S, Caliandro G. A, Cameron R. A, Caraveo P. A, Carrigan S, Casandjian J. M, Cavazzuti E, Cecchi C, Celik Oe, Chekhtman A, Cheung C. C, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Corbel S, Cutini S, D'Ammando F, Dermer C. D, de Angelis A, de Palma F, Digel S. W, do Couto e, Silva E, Drell P. S, Dubois R, Dumora D, Escande L, Favuzzi C, Fegan S. J, Ferrara E. C, Fuhrmann L, Fukazawa Y, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giebels B, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier I. A, Grove J. E, Guiriec S, Hadasch D, Hayashida M, Hays E, Johannesson G, Johnson A. S, Johnson W. N, Kamae T, Katagiri H, Kataoka J, Knoedlseder J, Kuss M, Lande J, Larsson S, Latronico L, Lee S. -H, Garde M. Llena, Longo F, Loparco F, Lott B, Lubrano P, Madejski G. M, Makeev A, Marchili N, Mazziotta M. N, McEnery J. E, Mehault J, Michelson P. F, Mizuno T, Monte C, Monzani M. E, Morselli A, Moskalenko I. V, Murgia S, Nakamori T, Nalewajko K, Naumann-Godo M, Nolan P. L, Norris J. P, Nuss E, Ohsugi T, Okumura A, Omodei N, Orlando E, Ormes J. F, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter T. A, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Reyes L. C, Ripken J, Ritz S, Roth M, Sadrozinski H. F. -W, Sanchez D, Sander A, Scargle J. D, Sgro C, Sikora M, Siskind E. J, Spandre G, Spinelli P, Strickman M. S, Suson D. J, Takahashi H, Takahashi T, Tanaka T, Tanaka Y, Thayer J. B, Thayer J. G, Thompson D. J, Tibaldo L, Torres D. F, Tosti G, Tramacere A, Usher T. L, Vandenbroucke J, Vilchez N, Vitale V, Waite A. P, Wang P, Wehrle A. E, Winer B. L, Yang Z, Ylinen T, Ziegler M

    ASTROPHYSICAL JOURNAL   721 ( 2 ) 1383 - 1396  2010.10  [Refereed]

     View Summary

    The flat spectrum radio quasar 3C 454.3 underwent an extraordinary outburst in 2009 December when it became the brightest γ -ray source in the sky for over 1 week. Its daily flux measured with the Fermi-Large Area Telescope at photon energiesE > 100 MeV reached F100 = 22 ± 1 × 10 -6 photon cm-2 s-1, representing the highest daily flux of any blazar ever recorded in high-energy γ -rays. It again became the brightest source in the sky in 2010 April, triggering a pointed-mode observation by Fermi. The correlated γ -ray temporal and spectral properties during these exceptional events are presented and discussed. The main results show flux variability over time scales less than 3 hr and very mild spectral variability with an indication of gradual hardening preceding major flares. The light curves during periods of enhanced activity in 2008 July-August and 2010 December show strong resemblance, with a flux plateau of a few days preceding the major flare. No consistent loop pattern emerged in the γ -ray spectral index versus the flux plane as would be expected in acceleration and cooling scenarios. The maximum energy of a photon from 3C 454.3 is ≈20 GeV and a minimum Doppler factor of ≈13 is derived. The γ -ray spectrum of 3C 454.3 shows a significant spectral break between ≈2 and 3 GeV that is very weakly dependent on the flux state, even when the flux changes by an order of magnitude. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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  • Development of X-ray/Gamma-ray Imaging Spectrometer with Reach-through APD arrays

    Nakamori, T, Enomoto, T, Toizumi, T, Yatsu, Y, Kawai, N, Kataoka, J, Ishikawa, Y, Kawai, T, Kawabata, N, Matsunaga, Y

    AIP Conference Proceedings   1279   400 - 402  2010.10

     View Summary

    It is quite important to obtain wide band spectra of high energy astrophysical phenomena at the same time in order to probe emission processes or structures. Especially observations of transient objects, such as gamma-ray bursts, expect detectors with wide energy band coverage for the sake of an efficient spectroscopy within limited time windows. An avalanche photo diode (APD) is a compact photon sensor with an internal gain of ∼100. We have developed an X-ray/gamma-ray detector using a reach-through APD (5 × 5 mm2) optically coupled with a conventional CsI(Tl) scintillator, which covers typically from 1 keV to 1 MeV. Further, we developed a 1-dimensional array of the 8/16 APDs (net 16 × 20) mm2) for the purpose of an imaging photon detector combined with coded masks, to be applied in future missions. We present the current status and performances of our hybrid detector using the 8-channel array. © 2010 American Institute of Physics.

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  • Development of an APD-Based PET Module and Preliminary Resolution Performance of an Experimental Prototype Gantry

    Jun Kataoka, Hidenori Matsuda, Fumihiko Nishikido, Makoto Koizumi, Hirokazu Ikeda, Masao Yoshino, Takamasa Miura, Satoshi Tanaka, Yoshitaka Ishikawa, Nobuyuki Kawabata, Keiji Shimizu, Yusuke Matsunaga, Shunji Kishimoto, Hidetoshi Kubo, Yoshio Yanagida, Takeshi Nakamori

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   57 ( 5 ) 2448 - 2454  2010.10

     View Summary

    The development of a high-resolution Positron Emission Tomography (PET) technique with sub-millimeter spatial resolution, which utilizes newly designed reverse-type APD-arrays, is uderway. All the detector blocks are modularized with the overall dimension of each module, including the APD array, LYSO scintillator matrix and Front-End Circuits (FECs), which are only 30 x 30 x 80 mm(3). Each APD device also has a monolithic 16 x 16 pixel structure with an active area of 1.0 mm(2) per pixel. The FEC includes two identical analog ASICs specifically designed for APDs with a noise characteristic of 560 + 30 e(-)/pF and a timing resolution of 460 ps (rms), respectively. An energy resolution of 13.7 +/- 1.1% (FWHM) with 662 keV gamma-rays was measured using the 16 x 16 arrays. At this stage a pair of module and coincidence circuits has been assembled into an experimental prototype gantry. Spatial resolutions of 0.9, 1.4, and 1.3 mm (FWHM) were obtained from FBP reconstructed images in preliminary experiments with a point source positioned centrally, and 1 and 5 mm off-center, respectively. Comparison with a Monte-Carlo simulation of a fully-designed gantry over a wider range of field-of-view showed good correlation with the experimental data. A simple but conceptual design of a DOI configuration is also proposed as a test example of a future APD-PET scanner.

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  • Development of an APD-Based PET Module and Preliminary Resolution Performance of an Experimental Prototype Gantry

    Jun Kataoka, Hidenori Matsuda, Fumihiko Nishikido, Makoto Koizumi, Hirokazu Ikeda, Masao Yoshino, Takamasa Miura, Satoshi Tanaka, Yoshitaka Ishikawa, Nobuyuki Kawabata, Keiji Shimizu, Yusuke Matsunaga, Shunji Kishimoto, Hidetoshi Kubo, Yoshio Yanagida, Takeshi Nakamori

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   57 ( 5 ) 2448 - 2454  2010.10  [Refereed]

     View Summary

    The development of a high-resolution Positron Emission Tomography (PET) technique with sub-millimeter spatial resolution, which utilizes newly designed reverse-type APD-arrays, is uderway. All the detector blocks are modularized with the overall dimension of each module, including the APD array, LYSO scintillator matrix and Front-End Circuits (FECs), which are only 30 x 30 x 80 mm(3). Each APD device also has a monolithic 16 x 16 pixel structure with an active area of 1.0 mm(2) per pixel. The FEC includes two identical analog ASICs specifically designed for APDs with a noise characteristic of 560 + 30 e(-)/pF and a timing resolution of 460 ps (rms), respectively. An energy resolution of 13.7 +/- 1.1% (FWHM) with 662 keV gamma-rays was measured using the 16 x 16 arrays. At this stage a pair of module and coincidence circuits has been assembled into an experimental prototype gantry. Spatial resolutions of 0.9, 1.4, and 1.3 mm (FWHM) were obtained from FBP reconstructed images in preliminary experiments with a point source positioned centrally, and 1 and 5 mm off-center, respectively. Comparison with a Monte-Carlo simulation of a fully-designed gantry over a wider range of field-of-view showed good correlation with the experimental data. A simple but conceptual design of a DOI configuration is also proposed as a test example of a future APD-PET scanner.

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  • Fermi-LAT observations of the Geminga pulsar

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, G.F. Bignami, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, F.D. Palma, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knódlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainó, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgró, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K. Watters, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   720 ( 1 ) 272 - 283  2010.09  [Refereed]

     View Summary

    We report on the Fermi-LAT observations of the Geminga pulsar, the second brightest non-variable GeV source in the γ-ray sky and the first example of a radio-quiet γ-ray pulsar. The observations cover one year, from the launch of the Fermi satellite through 2009 June 15. A data sample of over 60,000 photons enabled us to build a timing solution based solely on γ-rays. Timing analysis shows two prominent peaks, separated by Δφ = 0.497 ± 0.004 in phase, which narrow with increasing energy. Pulsed γ -rays are observed beyond 18 GeV, precluding emission below 2.7 stellar radii because of magnetic absorption. The phase-averaged spectrum was fitted with a power law with exponential cutoff of spectral index Γ = (1.30 ± 0.01 ±0.04), cutoff energy E0 = (2.46 ± 0.04 ± 0.17) GeV, and an integral photon flux above 0.1 GeV of (4.14 ± 0.02 ± 0.32) × 10-6 cm-2 s-1. The first uncertainties are statistical and the second ones are systematic. The phase-resolved spectroscopy shows a clear evolution of the spectral parameters, with the spectral index reaching a minimum value just before the leading peak and the cutoff energy having maxima around the peaks. The phase-resolved spectroscopy reveals that pulsar emission is present at all rotational phases. The spectral shape, broad pulse profile, and maximum photon energy favor the outer magnetospheric emission scenarios. © 2010. The American Astronomical Society. All rights reserved.

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  • The Fermi-LAT high-latitude survey: Source count distributions and the origin of the extragalactic diffuse background

    A.A. Abdo, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, S.E. Healey, D. Horan, R.E. Hughes, R. Itoh, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgró, M.S. Shaw, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   720 ( 1 ) 435 - 453  2010.09  [Refereed]

     View Summary

    This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the Fermi-LAT survey. In this work, we focus on the intrinsic spectral and flux properties of the source sample. We show that when selection effects are properly taken into account, Fermi sources are on average steeper than previously found (e.g., in the bright source list) with an average photon index of 2.40 ± 0.02 over the entire 0.1-100 GeV energy band. We confirm that flat spectrum radio quasars have steeper spectra than BL Lacertae objects with an average index of 2.48 ± 0.02 versus 2.18 ± 0.02. Using several methods, we build the deepest source count distribution at GeV energies, deriving that the intrinsic source (i.e., blazar) surface density at F100 ≥ 10-9 ph cm -2 s-1 is 0.12+0.03-0.02deg- -2. The integration of the source count distribution yields that point sources contribute 16(±1.8)% (±7% systematic uncertainty) of the GeV isotropic diffuse background. At the fluxes currently reached by LAT, we can rule out the hypothesis that pointlike sources (i.e., blazars) produce a larger fraction of the diffuse emission. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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  • Fermi Large Area Telescope observations of gamma-ray pulsars PSR J1057-5226, J1709-4429, and J1952+3252

    A.A. Abdo, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, F. Camilo, P.A. Caraveo, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Favuzzi, E.C. Ferrara, P. Fortin, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A.K. Harding, E. Hays, G. Jóhannesson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, P. Lubrano, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J.F. Ormes, M. Ozaki, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, S. Rainò, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, R.W. Romani, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, J. Vandenbroucke, V. Vasileiou, V. Vitale, A.P. Waite, P. Wang, P. Weltevrede, B.L. Winer, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   720 ( 1 ) 26 - 40  2010.09  [Refereed]

     View Summary

    The Fermi Large Area Telescope (LAT) data have confirmed the pulsed emission from all six high-confidence gamma-ray pulsars previously known from the EGRET observations. We report results obtained from the analysis of 13 months of LAT data for three of these pulsars (PSR J1057-5226, PSR J1709-4429, and PSR J1952+3252) each of which had some unique feature among the EGRET pulsars. The excellent sensitivity of LAT allows more detailed analysis of the evolution of the pulse profile with energy and also of the variation of the spectral shape with phase. We measure the cutoff energy of the pulsed emission from these pulsars for the first time and provide a more complete picture of the emission mechanism. The results confirm some, but not all, of the features seen in the EGRET data. © 2010. The American Astronomical Society.

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  • Fermi Large Area Telescope observations of misaligned active galactic nuclei

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Celotti, E. Charles, A. Chekhtman, A.W. Chen, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, D.S. Davis, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, C. Favuzzi, S.J. Fegan, E.C. Ferrara, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, G. Malaguti, M.N. Mazziotta, W. McConville, J.E. McEnery, P.F. Michelson, G. Migliori, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, M. Naumann-Godo, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Persic, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L.C. Reyes, M. Roth, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, Ł. Stawarz, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, E. Torresi, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   720 ( 1 ) 912 - 922  2010.09  [Refereed]

     View Summary

    Analysis is presented for 15 months of data taken with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope for 11 non-blazar active galactic nuclei (AGNs), including seven FRI radio galaxies and four FRII radio sources consisting of two FRII radio galaxies and two steep spectrum radio quasars. The broad line FRI radio galaxy 3C 120 is reported here as a γ -ray source for the first time. The analysis is based on directional associations of LAT sources with radio sources in the 3CR, 3CRR, and MS4 (collectively referred to as 3C-MS) catalogs. Seven of the eleven LAT sources associated with 3C-MS radio sources have spectral indices larger than 2.3 and, except for the FRI radio galaxy NGC 1275 that shows possible spectral curvature, are well described by a power law. No evidence for time variability is found for any sources other than NGC 1275. The γ-ray luminosities of FRI radio galaxies are significantly smaller than those of the BL Lac objects detected by the LAT, whereas the γ -ray luminosities of the FRII sources are quite similar to those of FSRQs, which could reflect different beaming factors for the γ -ray emission. A core dominance (CD) study of the 3CRR sample indicates that sources closer to the jet axis are preferentially detected with the Fe r m i LAT, insofar as the γ -ray-detected misaligned AGNs have larger CD at a given average radio flux. The results are discussed in view of the AGN unification scenario. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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  • Fermi Large Area Telescope view of the core of the radio galaxy Centaurus A

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, T.J. Brandt, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L.R. Cominsky, J. Conrad, L. Costamante, D.S. Davis, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, A. Falcone, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, H. Hase, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, T. Kishishita, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, C. Müller, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, R. Ojha, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, C. Pagani, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, C. Plötz, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, J.D. Scargle, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, L. Stawarz, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, J. Vandenbroucke, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   719 ( 2 ) 1433 - 1444  2010.08  [Refereed]

     View Summary

    We present γ-ray observations with the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope of the nearby radio galaxy Centaurus A (Cen A). The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of the lobes by the LAT; in this work, we concentrate on the γ-ray core of Cen A. Flux levels as seen by the LAT are not significantly different from that found by EGRET, nor is the extremely soft LAT spectrum (Γ = 2.67 ± 0.10stat ± 0.08sys where the photon flux is Φ α E-Γ). The LAT core spectrum, extrapolated to higher energies, is marginally consistent with the non-simultaneous HESS spectrum of the source. The LAT observations are complemented by simultaneous observations from Suzaku, the Swift Burst Alert Telescope and X-ray Telescope, and radio observations with the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry program, along with a variety of non-simultaneous archival data from a variety of instruments and wavelengths to produce a spectral energy distribution (SED). We fit this broadband data set with a single-zone synchrotron/synchrotron self-Compton model, which describes the radio through GeV emission well, but fails to account for the non-simultaneous higher energy TeV emission observed by HESS from 2004 to 2008. The fit requires a low Doppler factor, in contrast to BL Lac objects which generally require larger values to fit their broadband SEDs. This indicates that the γ-ray emission originates from a slower region than that from BL Lac objects, consistent with previous modeling results from Cen A. This slower region could be a slower moving layer around a fast spine, or a slower region farther out from the black hole in a decelerating flow. The fit parameters are also consistent with Cen A being able to accelerate ultra-high energy cosmic-rays, as hinted at by results from the Auger observatory. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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  • Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni

    Abdo, A. A, Ackermann, M, Ajello, M, Atwood, W. B, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, R. D, Bloom, E. D, Bonamente, E, Borgland, A. W, Bouvier, A, Brandt, T. J, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Buehler, R, Burnett, T. H, Buson, S, Caliandro, G. A, Cameron, R. A, Caraveo, P. A, Carrigan, S, Casandjian, J. M, Cecchi, C, Celik, O, Charles, E, Chaty, S, Chekhtman, A, Cheung, C. C, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Corbel, S, Corbet, R, DeCesar, M. E, den Hartog, P. R, Dermer, C. D, de Palma, F, Digel, S. W, Donato, D, do Couto e, Silva, E, Drell, P. S, Dubois, R, Dubus, G, Dumora, D, Favuzzi, C, Fegan, S. J, Ferrara, E. C, Fortin, P, Frailis, M, Fuhrmann, L, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, I. A, Grondin, M. -H, Grove, J. E, Guiriec, S, Hadasch, D, Harding, A. K, Hayashida, M, Hays, E, Healey, S. E, Hill, A. B, Horan, D, Hughes, R. E, Itoh, R, Jean, P, Johannesson, G, Johnson, A. S, Johnson, R. P, Johnson, T. J, Johnson, W. N, Kamae, T, Katagiri, H, Kataoka, J, Kerr, M, Knodlseder, J, Koerding, E, Kuss, M, Lande, J, Lande, J, Lee, S. -H, Lemoine-Goumard, M, Llena Garde, M, Longo, F, Loparco, F, Lott, B, Lovellette, M. N, Lubrano, P, Makeev, A, Mazziotta, M. N, McConville, W, McEnery, J. E, Mehault, J, Michelson, P. F, Mizuno, T, Moiseev, A. A, Monte, C, Monzani, M. E, Morselli, A, Moskalenko, I. V, Murgia, S, Nakamori, T, Naumann-Godo, M, Nestoras, I, Nolan, P. L, Norris, J. P, Nuss, E, Ohno, M, Ohsugi, T, Okumura, A, Omodei, N, Orlando, E, Ormes, J. F, Ozaki, M, Paneque, D, Panetta, J. H, Parent, D, Pelassa, V, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, T. A, Raino, S, Rando, R, Ray, P. S, Razzano, M, Razzaque, S, Rea, N, Reimer, A, Reimer, O, Reposeur, T, Ripken, J, Ritz, S, Romani, R. W, Roth, M, Sadrozinski, H. F. W, Sander, A, Parkinson, P. M. Saz, Scargle, J. D, Schinzel, F. K, Sgro, C, Shaw, M. S, Siskind, E. J, Smith, D. A, Smith, P. D, Sokolovsky, K. V, Spandre, G, Spinelli, P, Stawarz, L, Strickman, M. S, Suson, D. J, Takahashi, H, Takahashi, T, Tanaka, T, Tanaka, Y, Thayer, J. B, Thayer, J. G, Thompson, D. J, Tibaldo, L, Torres, D. F, Tosti, G, Tramacere, A, Uchiyama, Y, Usher, T. L, Vandenbroucke, J, Vasileiou, V, Vilchez, N, Vitale, V, Waite, A. P, Wallace, E, Wang, P, Winer, B. L, Wolff, M. T, Wood, K. S, Yang, Z, Ylinen, T, Ziegler, M, Maehara, H, Nishiyama, K, Kabashima, F, Bach, U, Bower, G. C, Falcone, A, Forster, J. R, Henden, A, Kawabata, K. S, Koubsky, P, Mukai, K, Nelson, T, Oates, S. R, Sakimoto, K, Sasada, M, Shenavrin, V. I, Shore, S. N, Skinner, G. K, Sokoloski, J, Stroh, M, Tatarnikov, A

    SCIENCE   329 ( 5993 ) 817 - 821  2010.08  [Refereed]

     View Summary

    Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

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  • フェルミ衛星による活動銀河ジェット観測の新展開

    片岡 淳ほか

    日本天文学会誌   103   486  2010.08

  • FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE SUPERNOVA REMNANT W28 (G6.4-0.1)

    Abdo A. A, Ackermann M, Ajello M, Allafort A, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Blandford R. D, Bloom E. D, Bonamente E, Borgland A. W, Bouvier A, Br, dt T. J, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro G. A, Cameron R. A, Caraveo P. A, Carrigan S, Casandjian J. M, Cecchi C, Celik Oe, Chekhtman A, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Dermer C. D, de Palma F, do Couto e, Silva E, Drell P. S, Dubois R, Dumora D, Farnier C, Favuzzi C, Fegan S. J, Fukazawa Y, Fukui Y, Funk S, Fusco P, Gargano F, Gehrels N, Germani S, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier I. A, Grove J. E, Guiriec S, Hadasch D, Hanabata Y, Harding A. K, Hays E, Horan D, Hughes R. E, Johannesson G, Johnson A. S, Johnson W. N, Kamae T, Katagiri H, Kataoka J, Knoedlseder J, Kuss M, Lande J, Latronico L, Lee S. -H, Lemoine-Goumard M, Garde M. Llena, Longo F, Loparco F, Lovellette M. N, Lubrano P, Makeev A, Mazziotta M. N, Michelson P. F, Mitthumsiri W, Mizuno T, Moiseev A. A, Monte C, Monzani M. E, Morselli A, Moskalenko I. V, Murgia S, Nakamori T, Nolan P. L, Norris J. P, Nuss E, Ohno M, Ohsugi T, Omodei N, Orlando E, Ormes J. F, Ozaki M, Panetta J. H, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter T. A, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Reposeur T, Rodriguez Y, Roth M, Sadrozinski H. F. -W, Sander A, Parkinson P, M. Saz, Sgro C, Siskind E. J, Smith D. A, Smith P. D, Spandre G, Spinelli P, Strickman M. S, Suson D. J, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer J. B, Thayer J. G, Thompson D. J, Tibaldo L, Tibolla O, Torres D. F, Tosti G, Uchiyama Y, Uehara T, Usher T. L, Vasileiou V, Vilchez N, Vitale V, Waite A. P, Wang P, Winer B. L, Wood K. S, Yamamoto H, Yamazaki R, Yang Z, Ylinen T, Ziegler M

    ASTROPHYSICAL JOURNAL   718 ( 1 ) 348 - 356  2010.07  [Refereed]

     View Summary

    We present detailed analysis of two gamma-ray sources, 1FGL J1801.3-2322c and 1FGL J1800.5-2359c, that have been found toward the supernova remnant (SNR) W28 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. 1FGL J1801.3-2322c is found to be an extended source within the boundary of SNR W28, and to extensively overlap with the TeV gamma-ray source HESS J1801-233, which is associated with a dense molecular cloud interacting with the SNR. The gamma-ray spectrum measured with the LAT from 0.2 to 100 GeV can be described by a broken power-law function with a break at ∼1 GeV and photon indices of 2.09 ± 0.08 (stat) ± 0.28 (sys) below the break and 2.74 ± 0.06 (stat) ± 0.09 (sys) above the break. Given the clear association between HESS J1801-233 and the shocked molecular cloud and a smoothly connected spectrum in the GeV-TeV band, we consider the origin of the gamma-ray emission in both GeV and TeV ranges to be the interaction between particles accelerated in the SNR and the molecular cloud. The decay of neutral pions produced in interactions between accelerated hadrons and dense molecular gas provides a reasonable explanation for the broadband gamma-ray spectrum. 1FGL J1800.5-2359c, located outside the southern boundary of SNR W28, cannot be resolved. An upper limit on the size of the gamma-ray emission was estimated to be ∼16′ using events above ∼2 GeV under the assumption of a circular shape with uniform surface brightness. It appears to coincide with the TeV source HESS J1800-240B, which is considered to be associated with a dense molecular cloud that contains the ultra compact H ii region W28A2 (G5.89-0.39). We found no significant gamma-ray emission in the LAT energy band at the positions of TeV sources HESS J1800-230A and HESS J1800-230C. The LAT data for HESS J1800-230A combined with the TeV data points indicate a spectral break between 10 GeV and 100 GeV.

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  • GeV gamma-ray flux upper limits from clusters of galaxies

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, R. D. Blandford, P. Blasi, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Çelik, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L. R. Cominsky, J. Conrad, C. D. Dermer, F. De Palma, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, S. Guiriec, D. Hadasch, A. K. Harding, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, T. E. Jeltema, G. Jóhannesson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli

    Astrophysical Journal Letters   717 ( 1 ) L71 - L78  2010.07

     View Summary

    The detection of diffuse radio emission associated with clusters of galaxies indicates populations of relativistic leptons infusing the intraclustermedium (ICM). Those electrons and positrons are either injected into and accelerated directly in the ICM, or produced as secondary pairs by cosmic-ray ions scattering on ambient protons. Radiation mechanisms involving the energetic leptons together with the decay of neutral pions produced by hadronic interactions have the potential to produce abundant GeV photons. Here, we report on the search for GeV emission from clusters of galaxies using data collected by the Large Area Telescope on the FermiGamma-ray Space Telescope from 2008 August to 2010 February. Thirty-three galaxy clusters have been selected according to their proximity and high mass, X-ray flux and temperature, and indications of non-thermal activity for this study. We report upper limits on the photon flux in the range 0.2-100GeVtoward a sample of observed clusters (typical values (1-5)×10-9 photon cm-2 s-1) considering both point-like and spatially resolved models for the high-energy emission and discuss how these results constrain the characteristics of energetic leptons and hadrons, and magnetic fields in the ICM. The volume-averaged relativistic-hadron-to-thermal energy density ratio is found to be <5%-10% in several clusters.

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  • Faint Gamma-ray Sources Observed with Fermi-LAT

    FUKAZAWA Yasushi, KATAOKA Jun, TAKAHASHI Tadayuki, Behalf of the, Fermi LAT Collaboration

    The astronomical herald   103 ( 8 ) 494 - 500  2010.07

    CiNii

  • Recent Highlights from AGN Observations with Fermi-LAT

    KATAOKA Jun, FUKAZAWA Yasushi, STAWARZ Lukasz, SATO Rie, HAYASHIDA Masaaki, Behalf of the, Fermi LAT Collaboration

    The astronomical herald   103 ( 8 ) 486 - 493  2010.07

    CiNii

  • Fermi observations of GRB 090510: A short-hard gamma-ray burst with an additional, hard power-law component from 10 keV to GeV energies

    M. Ackermann, K. Asano, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, C.D. Dermer, F. De Palma, B.L. Dingus, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. Granot, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, A.K. Harding, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, R.M. Kippen, J. Knödlseder, D. Kocevski, C. Kouveliotou, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, S. McGlynn, C. Meegan, P. Mészros, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, H. Nakajima, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, W.S. Paciesas, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, R. Preece, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, S. Ritz, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, K. Toma, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, X.F. Wu, R. Yamazaki, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   716 ( 2 ) 1178 - 1190  2010.06  [Refereed]

     View Summary

    We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E peak = 3.9 ± 0.3MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 ± 0.03 that dominates the emission below ≈ 20keV and above ≈ 100MeV. The onset of the high-energy spectral component appears to be delayed by ≈ 0.1s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5+5.8-2.6GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Γ≳1200, using simple γγ opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ≈ 100keV-few MeV flux. Stricter high confidence estimates imply Γ ≳ 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered. © 2010. The American Astronomical Society. All rights reserved.

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  • Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states

    A.A. Abdo, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, A.W. Chen, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, S. Cutini, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, M. Hayashida, D. Horan, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, L.C. Reyes, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, R. Sambruna, A. Sander, R. Sato, C. Sgrò, M.S. Shaw, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, Ł. Stawarz, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler, F. Tavecchio, M. Sikora, P. Schady, P. Roming, M.M. Chester, L. Maraschi

    Astrophysical Journal Letters   716 ( 1 ) 835 - 849  2010.06  [Refereed]

     View Summary

    We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089, and 3C454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 1014Hz up to 1025Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Γ 3-5) or a blackbody-type emission with temperatures kT 0.1-0.2keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low- and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone. © 2010. The American Astronomical Society. All rights reserved.

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  • The spectral energy distribution of fermi bright blazars

    A.A. Abdo, M. Ackermann, I. Agudo, M. Ajello, H.D. Aller, M.F. Aller, E. Angelakis, A.A. Arkharov, M. Axelsson, U. Bach, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, E. Benitez, A. Berdyugin, B. Berenji, R.D. Blandford, E.D. Bloom, M. Boettcher, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, D. Burrows, S. Buson, G.A. Caliandro, L. Calzoletti, R.A. Cameron, M. Capalbi, P.A. Caraveo, D. Carosati, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, S. Chaty, A. Chekhtman, W.P. Chen, J. Chiang, G. Chincarini, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L.R. Cominsky, J. Conrad, L. Costamante, S. Cutini, F. D'Ammando, R. Deitrick, V. D'Elia, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, I. Donnarumma, E.D.C.E. Silva, P.S. Drell, R. Dubois, D. Dultzin, D. Dumora, A. Falcone, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, E. Forné, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, J.L. Gómez, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, A. Giuliani, T. Glanzman, G. Godfrey, I.A. Grenier, C. Gronwall, J.E. Grove, L. Guillemot, S. Guiriec, M.A. Gurwell, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, S.E. Healey, J. Heidt, D. Hiriart, D. Horan, E.A. Hoversten, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, S.G. Jorstad, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Kennea, M. Kerr, G. Kimeridze, J. Knödlseder, M.L. Kocian, E.N. Kopatskaya, E. Koptelova, T.S. Konstantinova, Y.Y. Kovalev, Yu.A. Kovalev, O.M. Kurtanidze, M. Kuss, J. Lande, V.M. Larionov, L. Latronico, P. Leto, E. Lindfors, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, P. Marchegiani, A.P. Marscher, F. Marshall, W. Max-Moerbeck, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, I. Nestoras, K. Nilsson, N.A. Nizhelsky, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, R. Ojha, N. Omodei, E. Orlando, J.F. Ormes, J. Osborne, M. Ozaki, L. Pacciani, P. Padovani, C. Pagani, K. Page, D. Paneque, J.H. Panetta, D. Parent, M. Pasanen, V. Pavlidou, V. Pelassa, M. Pepe, M. Perri, M. Pesce-Rollins, S. Piranomonte, F. Piron, C. Pittori, T.A. Porter, S. Puccetti, F. Rahoui, S. Rainò, C. Raiteri, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J.L. Richards, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, J.A. Ros, M. Roth, P. Roustazadeh, F. Ryde, H.F.-W. Sadrozinski, A. Sadun, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, A. Sellerholm, C. Sgrò, M.S. Shaw, L.A. Sigua, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. Stevenson, G. Stratta, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, L.O. Takalo, T. Tanaka, J

    Astrophysical Journal Letters   716 ( 1 ) 30 - 70  2010.06  [Refereed]

     View Summary

    We have conducted a detailed investigation of the broadband spectral properties of the γ-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi γ-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/γ-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these γ-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log ν-log ν Fν representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low- and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, αro, and optical to X-ray, αox, spectral slopes) and from the γ-ray spectral index. Our data show that the synchrotron peak frequency (νSpeak) is positioned between 1012.5 and 1014.5 Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10 13 and 1017 Hz in featureless BL Lacertae objects. We find that the γ-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter γ-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum γ-ray sources, the correlation between νSpeak and γ-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars. © 2010 The American Astronomical Society.

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  • Fermi large area telescope first source catalog

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, E. Antolini, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, F. Belli, B. Berenji, D. Bisello, R.D. Blandford, E.D. Bloom, E. Bonamente, J. Bonnell, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G. Busetto, S. Buson, G.A. Caliandro, R.A. Cameron, R. Campana, B. Canadas, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, M. Ceccanti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, R. Corbet, D.S. Davis, M. Deklotz, P.R. Den Hartog, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, D. Fabiani, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, S.E. Healey, A.B. Hill, D. Horan, R.E. Hughes, G. Iafrate, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, D. Kocevski, M. Kuss, J. Lande, D. Landriu, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, A.M. Lionetto, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, B. Marangelli, M. Marelli, E. Massaro, M.N. Mazziotta, W. McConville, J.E. McEnery, P.F. Michelson, M. Minuti, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, M. Mongelli, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, H. Nakajima, T. Nakamori, M. Naumann-Godo, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, A. Paccagnella, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pinchera, F. Piron, T.A. Porter, L. Poupard, S. Rainò, R. Rando, P.S. Ray, M. Razzano, S. Razzaque, N. Rea, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, D. Salvetti, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, G. Scolieri, C. Sgrò, M.S. Shaw, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, T.E. Stephens, E. Striani, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, F. Tinebra, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, K. Watters, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal, Supplement Series   188 ( 2 ) 405 - 436  2010.06  [Refereed]

     View Summary

    We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100MeV to 100GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4σ. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission. © 2010. The American Astronomical Society.

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    985
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  • Developments of large-area APD arrays for future applications to PET technology

    KATAOKA Jun

    Ionizing radiation.   35 ( 4 ) 277 - 287  2010.06

    CiNii

  • 大面積APDアレーの開発と次世代PET技術への展望

    片岡 淳

    放射線(応用物理学会・放射線分科会)   35 ( 4 ) 277 - 287  2010.06

    CiNii

  • The first catalog of active galactic nuclei detected by the Fermi large area telescope

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, E. Antolini, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, J.R. Bogart, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Celotti, E. Charles, A. Chekhtman, A.W. Chen, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, G. Cotter, S. Cutini, V. D'Elia, C.D. Dermer, A. De Angelis, F. De Palma, A. De Rosa, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, L. Escande, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I.A. Grenier, M.-H. Grondin, J.E. Grove, S. Guiriec, D. Hadasch, A.K. Harding, M. Hayashida, E. Hays, S.E. Healey, A.B. Hill, D. Horan, R.E. Hughes, G. Iafrate, R. Itoh, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, C. Lavalley, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, G. Malaguti, E. Massaro, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, S. Piranomonte, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, L. Stawarz, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G.B. Taylor, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, P. Ubertini, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   715 ( 1 ) 429 - 457  2010.05  [Refereed]

     View Summary

    We present the first catalog of active galactic nuclei (AGNs) detected by the Large Area Telescope (LAT), corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are detected with a test statistic greater than 25 and associated statistically with AGNs. Some LAT sources are associated with multiple AGNs, and consequently, the catalog includes 709 AGNs, comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs of other types, and 72 AGNs of unknown type. We also classify the blazars based on their spectral energy distributions as archival radio, optical, and X-ray data permit. In addition to the formal 1LAC sample, we provide AGN associations for 51 low-latitude LAT sources and AGN "affiliations" (unquantified counterpart candidates) for 104 high-latitude LAT sources without AGN associations. The overlap of the 1LAC with existing γ-ray AGN catalogs (LBAS, EGRET, AGILE, Swift, INTEGRAL, TeVCat) is briefly discussed. Various properties - such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities - and their correlations are presented and discussed for the different blazar classes. We compare the 1LAC results with predictions regarding the γ-ray AGN populations, and we comment on the power of the sample to address the question of the blazar sequence. © 2010. The American Astronomical Society. All rights reserved..

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  • In-orbit performance of avalanche photodiode as radiation detector on board the picosatellite Cute-1.7+APD II

    Kataoka, J, Toizumi, T, Nakamroi, T, Yatsu, Y, Tsubuku, Y, Kuramoto, Y, Enomoto, T, Usui, R, Kawai, N, Ashida, H, Omagari, K, Fujihashi, K, Inagawa, S, Miura, Y, Konda, Y, Miyashita, N, Matsunaga, S, Ishikawa, Y, Matsunaga, Y, Kawabata, N

    Journal of Geophysical Research   115 ( 5 ) A05204 - (9pp)  2010.05  [Refereed]

     View Summary

    The Cute-1.7+APD II, 10 15 20 cm3 in size and 5 kg in mass, is the third picosatellite developed by students at the Tokyo Institute of Technology. One of the primary goals of the Cute-1.7+APD II mission is to validate the use of avalanche photodiodes (APDs) as a radiation detector for the first time in a space experiment. While the mission itself is immature compared to the forefront satellites of space plasma physics, use of APDs offers various possibilities regarding a brand-new electron energy analyzer for medium-energy electrons and ions (1-100 keV), as well as a high-performance light sensor for the future X-ray astronomy missions. The satellite was successfully launched by ISRO PSLV-C9 rocket on 28 April 2008 and has since been in operation for more than a year. The Cute-1.7+APD II carries two reverse-type APDs to monitor the distribution of low-energy particles (mainly electrons and protons) down to 9.2 keV trapped in a low Earth orbit (LEO), including the South Atlantic Anomaly (SAA) as well as aurora bands. We present the design parameters and various preflight tests of the APDs prior to launch, particularly, the high counting response and active gain control system for the Cute-1.7+APD II mission. Examples of electron/proton distribution, obtained in continuous 12 h observations, will be presented to demonstrate the initial flight performance of the APDs in orbit. Copyright 2010 by the American Geophysical Union.

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    41
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  • Fermi gamma-ray imaging of a radio galaxy

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L.R. Cominsky, J. Conrad, L. Costamante, S. Cutini, D.S. Davis, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starek, L. Stawarz, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler, M.J. Hardcastle, D. Kazanas

    Science   328 ( 5979 ) 725 - 729  2010.05  [Refereed]

     View Summary

    The Fermi Gamma-ray Space Telescope has detected the y-ray glow emanating from the giant radio lobes of the radio galaxy Centaurus A. The resolved y-ray image shows the lobes clearly separated from the central active source. In contrast to all other active galaxies detected so far in high-energy γ-rays, the lobe flux constitutes a considerable portion (greater than one-half) of the total source emission. The γ-ray emission from the lobes is interpreted as inverse Compton-scattered relic radiation from the cosmic microwave background, with additional contribution at higher energies from the infrared-to-optical extragalactic background light. These measurements provide γ-ray constraints on the magnetic field and particle energy content in radio galaxy lobes, as well as a promising method to probe the cosmic relic photon fields.

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    218
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  • Design of Tokyo Tech nano-satellite Cute-1.7+APD II and its operation

    Hiroki Ashida, Kota Fujihashi, Shinichi Inagawa, Yoshiyuki Miura, Kuniyuki Omagari, Naoki Miyashita, Saburo Matunaga, Takahiro Toizumi, Jun Kataoka, Nobuyuki Kawai

    Acta Astronautica   66 ( 9-10 ) 1412 - 1424  2010.05

     View Summary

    Cute-1.7+APD II is the 3rd satellite developed by the Laboratory for Space Systems at the Tokyo Institute of Technology. Cute-1.7+APD II is the current successor to Cute-1.7+APD. This new satellite is based on its predecessor but has some modifications to increase its reliability and robustness against radiation effects, electrical power shortage and so on. The satellite was launched by an ISRO PSLV-C9 rocket on April 28, 2008 and has operated for more than 9 months. Throughout its operation, many missions such as attitude determination and control experiments, scientific observations, photographing and communication experiments have been conducted. In this paper an overview of the Cute-1.7 series and configurations, modifications and operation results of Cute-1.7+APD II are introduced. © 2009 Elsevier Ltd. All rights reserved.

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    41
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  • Detection of the energetic pulsar PSR B1509-58 and its pulsar wind nebula in MSH 15-52 using the Fermi-large area telescope

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, P.R. Den Hartog, C.D. Dermer, A. De Luca, F. De Palma, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, E.V. Gotthelf, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, E. Hays, G. Hobbs, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, Y. Kanai, G. Kanbach, H. Katagiri, J. Kataoka, N. Kawai, M. Keith, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, J.E. McEnery, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, P. Weltevrede, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   714 ( 1 ) 927 - 936  2010.05  [Refereed]

     View Summary

    We report the detection of high-energy γ-ray emission from the young and energetic pulsar PSR B1509 - 58 and its pulsar wind nebula (PWN) in the composite supernova remnant G320.4 - 1.2 (aka MSH 15 - 52). Using 1 yr of survey data with the Fermi-Large Area Telescope (LAT), we detected pulsations from PSR B1509 - 58 up to 1GeV and extended γ-ray emission above 1GeV spatially coincident with the PWN. The pulsar light curve presents two peaks offset from the radio peak by phases 0.96 ± 0.01 and 0.33 ± 0.02. New constraining upper limits on the pulsar emission are derived below 1GeV and confirm a severe spectral break at a few tens ofMeV. The nebular spectrum in the 1-100GeV energy range is well described by a power law with a spectral index of (1.57 ± 0.17 ± 0.13) and a flux above 1GeV of (2.91 ± 0.79 ± 1.35) × 10-9cm-2s-1. The first errors represent the statistical errors on the fit parameters, while the second ones are the systematic uncertainties. The LAT spectrum of the nebula connects nicely with Cherenkov observations, and indicates a spectral break betweenGeV and TeV energies. © 2010 The American Astronomical Society. All rights reserved.

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  • Fermi-large area telescope observations of the exceptional gamma-ray outbursts of 3C 273 in 2009 September

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, L. Costamante, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, S. Guiriec, M. Hayashida, E. Hays, A.B. Hill, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, O. Mansutti, E. Massaro, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, A.E. Wehrle, B.L. Winer, K.S. Wood, Z. Yang, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   714 ( 1 ) L73 - L78  2010.05  [Refereed]

     View Summary

    We present the light curves and spectral data of two exceptionally luminous gamma-ray outbursts observed by the Large Area Telescope experiment on board the Fermi Gamma-ray Space Telescope from 3C 273 in 2009 September. During these flares, having a duration of a few days, the source reached its highest γ-ray flux ever measured. This allowed us to study, in some details, their spectral and temporal structures. The rise and the decay are asymmetric on timescales of 6 hr, and the spectral index was significantly harder during the flares than during the preceding 11 months. We also found that short, very intense flares put out the same time-integrated energy as long, less intense flares like that observed in 2009 August. © 2010. The American Astronomical Society.

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  • gamma-RAY SPECTRAL EVOLUTION OF NGC 1275 OBSERVED WITH FERMI LARGE AREA TELESCOPE

    J. Kataoka, L. Stawarz, C. C. Cheung, G. Tosti, E. Cavazzuti, A. Celotti, S. Nishino, Y. Fukazawa, D. J. Thompson, W. F. McConville

    ASTROPHYSICAL JOURNAL   715 ( 1 ) 554 - 560  2010.05  [Refereed]

     View Summary

    We report on a detailed investigation of the high-energy gamma-ray emission from NGC 1275, a well-known radio galaxy hosted by a giant elliptical located at the center of the nearby Perseus cluster. With the increased photon statistics, the center of the gamma-ray-emitting region is now measured to be separated by only 0.46 arcmin from the nucleus of NGC 1275, well within the 95% confidence error circle with radius similar or equal to 1.5 arcmin. Early Fermi Large Area Telescope (LAT) observations revealed a significant decade-timescale brightening of NGC 1275 at GeV photon energies, with a flux about 7 times higher than the one implied by the upper limit from previous EGRET observations. With the accumulation of one year of Fermi-LAT all-sky-survey exposure, we now detect flux and spectral variations of this source on month timescales, as reported in this paper. The average &gt; 100 MeV gamma-ray spectrum of NGC 1275 shows a possible deviation from a simple power-law shape, indicating a spectral cutoff around an observed photon energy of epsilon(gamma) = 42.2 +/- 19.6 GeV, with an average flux of F(gamma) = (2.31 +/- 0.13) x 10(-7) photons cm(-2) s(-1) and a power-law photon index, Gamma(gamma) = 2.13 +/- 0.02. The largest gamma-ray flaring event was observed in 2009 April-May and was accompanied by significant spectral variability above epsilon(gamma) greater than or similar to 1-2 GeV. The gamma-ray activity of NGC 1275 during this flare can be described by a hysteresis behavior in the flux versus photon index plane. The highest energy photon associated with the gamma-ray source was detected at the very end of the observation, with the observed energy of epsilon(gamma) = 67.4 GeV and an angular separation of about 2.4 arcmin from the nucleus. In this paper we present the details of the Fermi-LAT data analysis, and briefly discuss the implications of the observed gamma-ray spectral evolution of NGC 1275 in the context of gamma-ray blazar sources in general.

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  • The vela pulsar: Results from the first year of fermi lat observations

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, A. De Luca, F. De Palma, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, E. Hays, G. Hobbs, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K. Watters, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   713 ( 1 ) 154 - 165  2010.04  [Refereed]

     View Summary

    We report on analysis of timing and spectroscopy of the Vela pulsar using 11 months of observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the angular resolution and sensitivity of the LAT allows us to make the most detailed study to date of the energy-dependent light curves and phase-resolved spectra, using a LAT-derived timing model. The light curve consists of two peaks (P1 and P2) connected by bridge emission containing a third peak (P3). We have confirmed the strong decrease of the P1/P2 ratio with increasing energy seen with EGRET and previous Fermi LAT data, and observe that P1 disappears above 20 GeV. The increase with energy of the mean phase of the P3 component can be followed with much greater detail, showing that P3 and P2 are present up to the highest energies of pulsation. We find significant pulsed emission at phases outside the main profile, indicating that magnetospheric emission exists over 80% of the pulsar period. With increased high-energy counts the phase-averaged spectrum is seen to depart from a power law with simple exponential cutoff, and is better fit with a more gradual cutoff. The spectra in fixed-count phase bins are well fit with power laws with exponential cutoffs, revealing a strong and complex phase dependence of the cutoff energy, especially in the peaks. By combining these results with predictions of the outer magnetosphere models that map emission characteristics to phase, it will be possible to probe the particle acceleration and the structure of the pulsar magnetosphere with unprecedented detail. © 2010. The American Astronomical Society. All rights reserved.

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  • Fermi large area telescope observations of the vela-X pulsar wind nebula

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Chung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. De Angelis, F. De Palma, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, G. Giavitto, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   713 ( 1 ) 146 - 153  2010.04  [Refereed]

     View Summary

    We report on gamma-ray observations in the off-pulse window of the Vela pulsar PSR B0833-45 using 11 months of survey data from the Fermi Large Area Telescope (LAT). This pulsar is located in the 8° diameter Vela supernova remnant, which contains several regions of non-thermal emission detected in the radio, X-ray, and gamma-ray bands. The gamma-ray emission detected by the LAT lies within one of these regions, the 2° × 3° area south of the pulsar known as Vela-X. The LAT flux is significantly spatially extended with a best-fit radius of 088 012 for an assumed radially symmetric uniform disk. The 200 MeV to 20 GeV LAT spectrum of this source is well described by a power law with a spectral index of 2.41±0.09±0.15 and integral flux above 100 MeV of (4.73±0.63±1.32) × 10-7 cm -2 s-1. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Detailed morphological and spectral analyses give strong constraints on the energetics and magnetic field of the pulsar wind nebula system and favor a scenario with two distinct electron populations. © 2010. The American Astronomical Society. All rights reserved.

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  • Fermi large area telescope observations of PSR J1836+5925

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, A. Belfiore, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, C. Gwon, D. Hadasch, A.K. Harding, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, Y. Kanai, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, S.E. Thorsett, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K. Watters, B.L. Winer, M.T. Wolff, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   712 ( 2 ) 1209 - 1218  2010.04  [Refereed]

     View Summary

    The discovery of the γ-ray pulsar PSR J1836+5925, powering the formerly unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments of the Fermi Large Area Telescope (LAT). Sitting 25° off the Galactic plane, PSR J1836+5925 is a 173ms pulsar with a characteristic age of 1.8 million years, a spindown luminosity of 1.1 × 1034erg s-1, and a large off-peak (OP) emission component, making it quite unusual among the known γ-ray pulsar population. We present an analysis of one year of LAT data, including an updated timing solution, detailed spectral results, and a long-term light curve showing no indication of variability. No evidence for a surrounding pulsar wind nebula is seen and the spectral characteristics of the OP emission indicate it is likely magnetospheric. Analysis of recent XMM-Newton observations of the X-ray counterpart yields a detailed characterization of its spectrum, which, like Geminga, is consistent with that of a neutron star showing evidence for both magnetospheric and thermal emission. © 2010. The American Astronomical Society. All rights reserved. All rights reserved.

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  • The first fermi large area telescope catalog of gamma-ray pulsars

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, R. Corbet, S. Cutini, P.R. Den Hartog, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, E.V. Gotthelf, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, C. Gwon, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, G. Kanbach, V.M. Kaspi, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, G.M. Madejski, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, T. Mineo, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, A. Sellerholm, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, J.-L. Starck, E. Striani, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, N. Wang, K. Watters, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal, Supplement Series   187 ( 2 ) 460 - 494  2010.04  [Refereed]

     View Summary

    The dramatic increase in the number of known gamma-ray pulsars since the launch of the Fermi Gamma-ray Space Telescope (formerly GLAST) offers the first opportunity to study a sizable population of these high-energy objects. This catalog summarizes 46 high-confidence pulsed detections using the first six months of data taken by the Large Area Telescope (LAT), Fermi's main instrument. Sixteen previously unknown pulsars were discovered by searching for pulsed signals at the positions of bright gamma-ray sources seen with the LAT, or at the positions of objects suspected to be neutron stars based on observations at other wavelengths. The dimmest observed flux among these gamma-ray-selected pulsars is 6.0 × 10-8phcm-2s-1 (for E>100MeV). Pulsed gamma-ray emission was discovered from 24 known pulsars by using ephemerides (timing solutions) derived from monitoring radio pulsars. Eight of these new gamma-ray pulsars are millisecond pulsars. The dimmest observed flux among the radio-selected pulsars is 1.4 × 10 -8phcm-2s-1 (for E>100MeV). The remaining six gamma-ray pulsars were known since the Compton Gamma Ray Observatory mission, or before. The limiting flux for pulse detection is non-uniform over the sky owing to different background levels, especially near the Galactic plane. The pulsed energy spectra can be described by a power law with an exponential cutoff, with cutoff energies in the range 1-5GeV. The rotational energy-loss rate () of these neutron stars spans five decades, from 3 × 1033ergs-1 to 5 × 1038ergs-1, and the apparent efficiencies for conversion to gamma-ray emission range from 0.1% to unity, although distance uncertainties complicate efficiency estimates. The pulse shapes show substantial diversity, but roughly 75% of the gamma-ray pulse profiles have two peaks, separated by ≳0.2 of rotational phase. For most of the pulsars, gamma-ray emission appears to come mainly from the outer magnetosphere, while polar-cap emission remains plausible for a remaining few. Spatial associations imply that many of these pulsars power pulsar wind nebulae. Finally, these discoveries suggest that gamma-ray-selected young pulsars are born at a rate comparable to that of their radio-selected cousins and that the birthrate of all young gamma-ray-detected pulsars is a substantial fraction of the expected Galactic supernova rate. © 2010. The American Astronomical Society. All rights reserved..

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  • Discovery of pulsed γ-rays from PSR J0034-0534 with the fermi large area telescope: A case for co-located radio and γ-ray emission regions

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, J. Conrad, R. Corbet, M.E. Decesar, C.D. Dermer, G. Desvignes, A. De Angelis, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, A.K. Harding, E. Hays, G. Hobbs, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M.L. Garde, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, T.L. Usher, A. Vanetten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   712 ( 2 ) 957 - 963  2010.04  [Refereed]

     View Summary

    Millisecond pulsars (MSPs) have been firmly established as a class of γ-ray emitters via the detection of pulsations above 0.1GeV from eight MSPs by the Fermi Large Area Telescope (LAT). Using 13 months of LAT data, significant γ-ray pulsations at the radio period have been detected from the MSP PSR J0034-0534, making it the ninth clear MSP detection by the LAT. The γ-ray light curve shows two peaks separated by 0.274 ± 0.015 in phase which are very nearly aligned with the radio peaks, a phenomenon seen only in the Crab pulsar until now. The ≥0.1GeV spectrum of this pulsar is well fit by an exponentially cutoff power law with a cutoff energy of 1.8 ± 0.6 ± 0.1GeV and a photon index of 1.5 ± 0.2 ± 0.1, first errors are statistical and second are systematic. The near-alignment of the radio and γ-ray peaks strongly suggests that the radio and γ-ray emission regions are co-located and both are the result of caustic formation. © 2010. The American Astronomical Society.

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  • VLBI Monitoring of 3C 84 (NGC 1275) in Early Phase of the 2005 Outburst

    Hiroshi Nagai, Kenta Suzuki, Keiichi Asada, Motoki Kino, Seiji Kameno, Akihiro Doi, Makoto Inoue, Jun Kataoka, Uwe Bach, Tomoya Hirota, Naoko Matsumoto, Mareki Honma, Hideyuki Kobayashi, Kenta Fujisawa

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   62 ( 2 ) L11 - L15  2010.04  [Refereed]

     View Summary

    Multi-epoch Very Long Baseline Interferometry (VLBI) study of a sub-pc scale jet of 3C 84 is presented. We carried out 14-epoch VLBI observations during 2006-2009 with the Japanese VLBI Network and the VLBI Exploration of Radio Astrometry, immediately following a radio outburst that began in 2005. We confirmed that the outburst was associated with the central similar to 1 pc core, accompanying the emergence of a new component. This is striking evidence of the recurrence of jet activity. The new component became brighter during 2008, in contrast to constant gamma-ray emission that was observed with the Fermi Gamma-ray Space Telescope during the same time. We found that the projected speed of the new component was 0.23c from 2007/297 (2007 October 24) to 2009/114 (2009 April 24). The direction of movement of this component differs from that of the pre-existing component by similar to 40 degrees. This was the first measurement of the kinematics of a sub-pc jet in a gamma-ray active phase. A possible detection of jet deceleration and the jet kinematics in connection with the gamma-ray emission is discussed.

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  • Observations of Milky way dwarf spheroidal galaxies with the Fermi-large area telescope detector and constraints on dark matter models

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, A.K. Harding, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, T.E. Jeltema, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Profumo, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, M. Roth, H.F.-W. Sadrozinski, A. Sander, P.M.S. Parkinson, J.D. Scargle, T.L. Schalk, A. Sellerholm, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler, J.S. Bullock, M. Kaplinghat, G.D. Martinez

    Astrophysical Journal Letters   712 ( 1 ) 147 - 158  2010.03  [Refereed]

     View Summary

    We report on the observations of 14 dwarf spheroidal galaxies (dSphs) with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky γ-ray survey in the 20 MeV to >300GeV energy range, provides a new opportunity to test particle dark matter models through the expected γ-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dSphs, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant γ-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the γ-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10-9 photons cm-2 s-1. Using recent stellar kinematic data, the γ-ray flux limits are combined with improved determinations of the dark matter density profile in eight of the 14 candidate dwarfs to place limits on the pair-annihilation cross section of WIMPs in several widely studied extensions of the standard model, including its supersymmetric extension and other models that received recent attention. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g., in models where supersymmetry breaking occurs via anomaly mediation. The γ-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA e + e - data, including low-mass wino-like neutralinos and models with TeV masses pair annihilating into muon-antimuon pairs. © 2010. The American Astronomical Society.

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  • Observation of supernova remnant IC443 with the fermi large area telescope

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, C. Meurer, P.F. Michelson, W. Mitthumsiri, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   712 ( 1 ) 459 - 468  2010.03  [Refereed]

     View Summary

    We report observation of the supernova remnant (SNR) IC443 (G189.1+3.0) with the Fermi Gamma-ray Space Telescope Large Area Telescope (LAT) in the energy band between 200MeV and 50GeV. IC443 is a shell-type SNR with mixed morphology located off the outer Galactic plane where high-energy emission has been detected in the X-ray,GeV and TeV gamma-ray bands. Past observations suggest IC443 has been interacting with surrounding interstellar matter. Proximity between dense shocked molecular clouds andGeV-TeV gamma-ray emission regions detected by EGRET, MAGIC, and VERITAS suggests an interpretation that cosmic-ray (CR) particles are accelerated by the SNR. With the high gamma-ray statistics and broad energy coverage provided by the LAT, we accurately characterize the gamma-ray emission produced by the CRs accelerated at IC443. The emission region is extended in the energy band with θ68 = 027 001(stat) 003(sys) for an assumed two-dimensional Gaussian profile and overlaps almost completely with the extended source region of VERITAS. Its centroid is displaced significantly from the known pulsar wind nebula (PWN) which suggests the PWN is not the major contributor in the present energy band. The observed spectrum changes its power-law slope continuously and continues smoothly to the MAGIC and VERITAS data points. The combined gamma-ray spectrum (200MeV <E< 2 TeV) is reproduced well by decays of neutral pions produced by a broken power-law proton spectrum with a break around 70GeV. © 2010. The American Astronomical Society. All rights reserved.

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  • Fermi detection of delayed GeV emission from the short gamma-ray burst 081024B

    A.A. Abdo, M. Ackermann, M. Ajello, K. Asano, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, J.M. Burgess, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, Ö. Çelik, V. Chaplin, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, V. Connaughton, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, G. Fishman, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, J. Granot, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, R.H. Haynes, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, R.M. Kippen, J. Knödlseder, D. Kocevski, M.L. Kocian, N. Komin, C. Kouveliotou, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, S. McBreen, J.E. McEnery, S. McGlynn, C. Meegan, P. Mészros, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, W.S. Paciesas, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, R. Preece, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, S. Ritz, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, M.S. Strickman, D.J. Suson, G. Tagliaferri, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, K. Toma, D.F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, T.L. Usher, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, X.F. Wu, R. Yamazaki, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   712 ( 1 ) 558 - 564  2010.03  [Refereed]

     View Summary

    We report on the detailed analysis of the high-energy extended emission from the short gamma-ray burst (GRB) 081024B detected by the Fermi Gamma-ray Space Telescope. Historically, this represents the first clear detection of temporal extended emission from a short GRB. The light curve observed by the Fermi Gamma-ray Burst Monitor lasts approximately 0.8s whereas the emission in the Fermi Large Area Telescope lasts for about 3s. Evidence of longer lasting high-energy emission associated with long bursts has been already reported by previous experiments. Our observations, together with the earlier reported study of the bright short GRB 090510, indicate similarities in the high-energy emission of short and long GRBs and open the path to new interpretations. © 2010. The American Astronomical Society.

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  • Spectrum of the isotropic diffuse gamma-ray emission derived from first-year fermi large area telescope data

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö.Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, G. Di Bernardo, E.D.C. E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, Y. Hanabata, A.K. Harding, M. Hayashida, R.E. Hughes, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, A. Sellerholm, C. Sgrò, M.S. Shaw, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Physical Review Letters   104 ( 10 )  2010.03  [Refereed]

     View Summary

    We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called "extragalactic" diffuse γ-ray emission (EGB). This component of the diffuse γ-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic γ-ray emission, the detected LAT sources, and the solar γ-ray emission. We find the spectrum of the EGB is consistent with a power law with a differential spectral index γ=2.41±0.05 and intensity I(>100MeV)=(1. 03±0.17)×10-5cm-2s-1sr -1, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data. © 2010 The American Physical Society.

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  • Fermi large area telescope search for photon lines from 30 to 200 GeV and dark matter implications

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, Y. Edmonds, R. Essig, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, D. Horan, R. E. Hughes, M. S. Jackson, G. Jóhannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte

    Physical Review Letters   104 ( 9 )  2010.03

     View Summary

    Dark matter (DM) particle annihilation or decay can produce monochromatic γ rays readily distinguishable from astrophysical sources. γ-ray line limits from 30 to 200 GeV obtained from 11 months of Fermi Large Area Space Telescope data from 20-300 GeV are presented using a selection based on requirements for a γ-ray line analysis, and integrated over most of the sky. We obtain γ-ray line flux upper limits in the range 0.6-4.5×10-9cm-2s-1, and give corresponding DM annihilation cross-section and decay lifetime limits. Theoretical implications are briefly discussed. © 2010 The American Physical Society.

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  • PSR J1907+0602: A radio-faint gamma-ray pulsar powering a bright tev pulsar wind nebula

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, S.W. Digel, B.L. Dingus, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, M.S.E. Roberts, L.S. Rochester, A.Y. Rodriguez, R.W. Ro'Mani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K. Watters, B.L. Winer, M.T. Wolff, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   711 ( 1 ) 64 - 74  2010.03  [Refereed]

     View Summary

    We present multiwavelength studies of the 106.6 ms γ-ray pulsar PSR J1907+06 near the TeV source MGRO J1908+06. Timing observations with Fermi result in a precise position determination for the pulsar of R.A. = 19 h07m547(2), decl. = +06°02′16(2)″ placing the pulsar firmly within the TeV source extent, suggesting the TeV source is the pulsar wind nebula of PSR J1907+0602. Pulsed γ-ray emission is clearly visible at energies from 100 MeV to above 10 GeV. The phase-averaged power-law index in the energy range E > 0.1 GeV is Γ = 1.76 0.05 with an exponential cutoff energy Ec = 3.6 ± 0.5 GeV. We present the energy-dependent γ-ray pulsed light curve as well as limits on off-pulse emission associated with the TeV source. We also report the detection of very faint (flux density of ≃ 3.4 μJy) radio pulsations with the Arecibo telescope at 1.5 GHz having a dispersion measure DM = 82.1 1.1 cm-3 pc. This indicates a distance of 3.2 0.6 kpc and a pseudo-luminosity of L 1400 ≃ 0.035 mJy kpc2. A Chandra ACIS observation revealed an absorbed, possibly extended, compact (≲4″) X-ray source with significant nonthermal emission at R.A. = 19h07m5476, decl. = +06°02′146 with a flux of 2.3+0.6-1.4 × 10-14 erg cm-2 s-1. From archival ASCA observations, we place upper limits on any arcminute scale 2-10 keV X-ray emission of ∼1 × 10-13 erg cm-2 s-1. The implied distance to the pulsar is compatible with that of the supernova remnant G40.5 - 0.5, located on the far side of the TeV nebula from PSR J1907+0602, and the S74 molecular cloud on the nearer side which we discuss as potential birth sites.

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  • Gamma-ray emission from the shell of supernova remnant W44 revealed by the Fermi LAT

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farmer, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Katsuta, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, G.M. Madejski, A. Makeev, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Noms, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, F.W. Stecker, M.S. Strikman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, R. Yamazaki, T. Ylinen, M. Ziegler

    Science   327 ( 5969 ) 1103 - 1106  2010.02  [Refereed]

     View Summary

    Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ∼1015 electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 × 108 electron volts and 3 × 1011 electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above -109 electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space.

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  • SPECTRAL properties of bright fermi-detected blazars in the gamma-ray band

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Elik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, A.K. Harding, R.C. Hartman, M. Hayashida, E. Hays, S.E. Healey, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Persic, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   710 ( 2 ) 1271 - 1285  2010.02  [Refereed]

     View Summary

    The gamma-ray energy spectra of bright blazars of the LAT Bright AGN Sample (LBAS) are investigated using Fermi-LAT data. Spectral properties (hardness, curvature, and variability) established using a data set accumulated over 6 months of operation are presented and discussed for different blazar classes and subclasses: flat spectrum radio quasars (FSRQs), low-synchrotron peaked BLLacs (LSP-BLLacs), intermediate-synchrotron peaked BLLacs (ISP-BLLacs), and high-synchrotron peaked BLLacs (HSP-BLLacs). The distribution of photon index (Γ, obtained from a power-law fit above 100 MeV) is found to correlate strongly with blazar subclass. The change in spectral index from that averaged over the 6 months observing period is < 0.2-0.3 when the flux varies by about an order of magnitude, with a tendency toward harder spectra when the flux is brighter for FSRQs and LSP-BLLacs. A strong departure from a single power-law spectrum appears to be a common feature for FSRQs. This feature is also present for some high-luminosity LSP-BLLacs, and a small number of ISP-BLLacs. It is absent in all LBAS HSP-BLLacs. For 3C454.3 and AO0235+164, the two brightest FSRQ source and LSP-BLLac source, respectively, a broken power law (BPL) gives the most acceptable of power law, BPL, and curved forms. The consequences of these findings are discussed. © 2010. The American Astronomical Society.

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  • A change in the optical polarization associated with a γ-ray flare in the blazar 3C 279

    A.A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughmanl, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, D.C.-J. Bock, J.R. Bogart, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, W. Collmar, L.R. Cominsky, J. Conrad, S. Corbel, R. Corbet, L. Costamante, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Iafrate, R. Itoh, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, J. MacQuart, G.M. Madejski, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pavlidou, T.J. Pearson, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, T. Reposeur, L.C. Reyes, J.L. Richards, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, C. Shrader, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, L. Stawarz, M. Stevenson, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G.B. Taylor, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, A.E. Wehrle, B.L. Winer, K.S. Wood, T. Ylinen, J.A. Zensus, M. Ziegler, M. Uemura, Y. Ikejiri, K.S. Kawabata, M. Kino, K. Sakimoto, M. Sasada, S. Sato, M. Yamanaka, M. Villata, C.M. Raiteri, I. Agudo, H.D. Aller, M.F. Aller, E. Angelakis, A.A. Arkharov, U. Bach, E. Bený́tez, A. Berdyugin, D.A. Blinov, M. Boettcher, C.S. Buemi, W.P. Chen, M. Dolci, D. Dultzin, N.V. Efimova, M.A. Gurwell, C. Gusbar, J.L. Gómez, J. Heidt, D. Hiriart, T. Hovatta, S.G. Jorstad, T.S. Konstantinova, E.N. Kopatskaya, E. Koptelova, O.M

    Nature   463 ( 7283 ) 919 - 923  2010.02  [Refereed]

     View Summary

    It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma (γ)-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and γ-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10 5 gravitational radii. © 2010 Macmillan Publishers Limited. All rights reserved.

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  • PKS 1502+106: A new and distant gamma-ray blazar in outburst discovered by the fermi large area telescope

    E. Angelakis, A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, G. Bogaert, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M.L. Kocian, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, E. Massaro, W. Max-Moerbeck, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pavlidou, T.J. Pearson, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Readhead, A. Reimer, O. Reimer, T. Reposeur, J.L. Richards, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M. Stevenson, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, P. Ubertini, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, H. Yasuda, T. Ylinen, J.A. Zensus, M. Ziegler, E. Angelakis, T. Hovatta, E. Hoversten, Y. Ikejiri, K.S. Kawabata, Y.Y. Kovalev, Y.A. Kovalev, T.P. Krichbaum, M.L. Lister, A. Lähteenmäki, N. Marchili, P. Ogle, C. Pagani, A.B. Pushkarev, K. Sakimoto, M. Sasada, M. Tornikoski, M. Uemura, M. Yamanaka, T. Yamashita

    Astrophysical Journal Letters   710 ( 1 ) 810 - 827  2010.02  [Refereed]

     View Summary

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope discovered a rapid (5 days duration), high-energy (E > 100 MeV) gamma-ray outburst from a source identified with the blazar PKS 1502+106 (OR 103, S3 1502+10, z = 1.839) starting on 2008 August 5 (23 UTC, MJD 54683.95), and followed by bright and variable flux over the next few months. Results on the gamma-ray localization and identification, as well as spectral and temporal behavior during the first months of the Fermi all-sky survey, are reported here in conjunction with a multiwaveband characterization as a result of one of the first Fermi multifrequency campaigns. The campaign included a Swift ToO (followed up by a 16 day observation on August 7-22, MJD 54685-54700), VLBA (within the MOJAVE program), Owens Valley Radio Observatory (OVRO) 40 m, Effelsberg-100 m, Metsähovi-14 m, RATAN-600, and Kanata-Hiroshima radio/optical observations. Results from the analysis of archival observations by INTEGRAL, XMM-Newton, and Spitzer space telescopes are reported for a more complete picture of this new gamma-ray blazar. PKS 1502+106 is a sub-GeV peaked, powerful flat spectrum radio quasar (luminosity at E > 100 MeV, L γ, is about 1.1 × 1049 erg s-1, and black hole mass likely close to 109 M ), exhibiting marked gamma-ray bolometric dominance, in particular during the asymmetric outburst (L γ/L opt 100, and 5 day averaged flux F E > 100 MeV = 2.91 1.4 × 10-6 ph cm-2 s-1), which was characterized by a factor greater than 3 of flux increase in less than 12 hr. The outburst was observed simultaneously from optical to X-ray bands (F 0.3 - 10 keV = 2.18+0.15-0.12 × 10-12 erg cm-2 s-1, and hard photon index 1.5, similar to past values) with a flux increase of less than 1 order of magnitude with respect to past observations, and was likely controlled by Comptonization of external-jet photons produced in the broad-line region (BLR) in the gamma-ray band. No evidence of a possible blue bump signature was observed in the optical-UV continuum spectrum, while some hints for a possible 4 day time lag with respect to the gamma-ray flare were found. Nonetheless, the properties of PKS 1502+106 and the strict optical/UV, X-, and gamma-ray cross-correlations suggest the contribution of the synchrotron self-Compton (SSC), in-jet, process should dominate from radio to X-rays. This mechanism may also be responsible for the consistent gamma-ray variability observed by the LAT on longer timescales, after the ignition of activity at these energies provided by the BLR-dissipated outburst. Modulations and subsequent minor, rapid flare events were detected, with a general fluctuation mode between pink-noise and a random-walk. The averaged gamma-ray spectrum showed a deviation from a simple power law, and can be described by a log-parabola curved model peaking around 0.4-0.5 GeV. The maximum energy of photons detected from the source in the first four months of LAT observations was 15.8 GeV, with no significant consequences on extragalactic background light predictions. A possible radio counterpart of the gamma-ray outburst can be assumed only if a delay of more than three months is considered on the basis of opacity effects at cm and longer wavelengths. The rotation of the electric vector position angle observed by VLBA from 2007 to 2008 could represent a slow field ordering and alignment with respect to the jet axis, likely a precursor feature of the ejection of a superluminal radio knot and the high-energy outburst. This observing campaign provides more insight into the connection between MeV-GeV flares and the moving, polarized structures observed by the VLBI. © 2010. The American Astronomical Society. All rights reserved.

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  • Fermi-lat discovery of gev gamma-ray emission from the young supernova remnant cassiopeia A

    A.A. Abdo, M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T.H. Burnett, G. Busetto, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Corbel, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, E. Hays, A.K. Harding, M. Hayashida, D. Horan, R.E. Hughes, M.S. Jackson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, M. Pohl, T.A. Porter, S. Rainò, R. Rando, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, S.E. Thorsett, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, R. Yamazaki, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   710 ( 1 ) L92 - L97  2010.02  [Refereed]

     View Summary

    We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant (SNR) with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2σ above 500MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A (Cas A). The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W CR ≃ (1-4) × 1049 erg thanks to the well-known density in the remnant assuming that the observed gamma ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B ≥ 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta. © 2010. The American Astronomical Society. All rights reserved.

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  • Fermi observations of cassiopeia and cepheus: Diffuse gamma-ray emission in the outer galaxy

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, C.D. Dermer, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, A.K. Harding, M. Hayashida, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, A.Y. Rodriguez, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, C. Sgrò, E.J. Siskind, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, A.W. Strong, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   710 ( 1 ) 133 - 149  2010.02  [Refereed]

     View Summary

    We present the analysis of the interstellar γ-ray emission measured by the Fermi Large Area Telescope toward a region in the second Galactic quadrant at 100° ≤ l ≤ 145° and -15° ≤ b ≤ +30°. This region encompasses the prominent Gould Belt clouds of Cassiopeia, Cepheus, and the Polaris flare, as well as atomic and molecular complexes at larger distances, like that associated with NGC 7538 in the Perseus arm. The good kinematic separation in velocity between the local, Perseus, and outer arms, and the presence of massive complexes in each of them, make this region well suited to probe cosmic rays (CRs) and the interstellar medium beyond the solar circle. The γ-ray emissivity spectrum of the gas in the Gould Belt is consistent with expectations based on the locally measured CR spectra. The γ-ray emissivity decreases from the Gould Belt to the Perseus arm, but the measured gradient is flatter than expectations for CR sources peaking in the inner Galaxy as suggested by pulsars. The X CO = N(H2)/W CO conversion factor is found to increase from (0.87 ± 0.05) × 1020cm-2 (Kkms-1)-1 in the Gould Belt to (1.9 ± 0.2) × 1020cm-2 (Kkms -1)-1 in the Perseus arm. We derive masses for the molecular clouds under study. Dark gas, not properly traced by radio and microwave surveys, is detected in the Gould Belt through a correlated excess of dust and γ-ray emission: its mass amounts to 50% of the CO-traced mass. © 2010. The American Astronomical Society.

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  • Detection of gamma-ray emission from the starburst galaxies m82 and ngc 253 with the large area telescope on fermi

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, O. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C.D. Dermer, A. Deangelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, L. Foschini, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, A. Sander, P.M. Saz Parkinson, J.D. Scargle, A. Sellerholm, C. Sgrò, M.S. Shaw, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, A.W. Strong, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   709 ( 2 ) L152 - L157  2010.02  [Refereed]

     View Summary

    We report the detection of high-energy γ-ray emission from two starburst galaxies using data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Steady point-like emission above 200MeV has been detected at significance levels of 6.8σ and 4.8σ, respectively, from sources positionally coincident with locations of the starburst galaxies M82 and NGC 253. The total fluxes of the sources are consistent with γ-ray emission originating from the interaction of cosmic rays with local interstellar gas and radiation fields and constitute evidence for a link between massive star formation and γ-ray emission in star-forming galaxies. © 2010. The American Astronomical Society. All rights reserved.

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  • X-ray Polarimetry Small Satellite TSUBAME

    Toizumi, T, Enomoto, Usui, R, Nakamori, T, Yatsu, Y, Kawai, N, Kataoka, J, Omagari, K, Nishida, J, Inagawa, S, Matsunaga, S

    Proceedings of the 3rd Suzaku Conference     444 - 445  2010.02

  • Fermi large area telescope observations of the crab pulsar and nebula

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, K. Watters, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   708 ( 2 ) 1254 - 1267  2010.01  [Refereed]

     View Summary

    We report on γ-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nançay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first γ-ray peak leads the radio main pulse by (281 ±12 ± 21) μs, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to γ-ray statistics, and the second arises from the rotation parameters. The improved sensitivity and the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at Ec = (5.8 ± 0.5 ± 1.2) GeV, spectral index of Γ = (1.97 ± 0.02 ± 0.06) and integral photon flux above 100 MeV of (2.09 ± 0.03 ± 0.18) × 10-6 cm-2 s-1. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed γ-ray photons are observed up to 20 GeV which precludes emission near the stellar surface, below altitudes of around 4-5 stellar radii in phase intervals encompassing the two main peaks. A detailed phase-resolved spectral analysis is also performed: the hardest emission from the Crab Pulsar comes from the bridge region between the two γ-ray peaks while the softest comes from the falling edge of the second peak. The spectrum of the nebula in the energy range 100 MeV-300 GeV is well described by the sum of two power laws of indices Γsync = (3.99 ± 0.12 ± 0.08) and ΓIC = (1.64 ± 0.05 ± 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism. © 2010. The American Astronomical Society.

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  • Fermi observations of the very hard gamma-ray blazar PG1553+113

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, E.D.C.E. Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   708 ( 2 ) 1310 - 1320  2010.01  [Refereed]

     View Summary

    We report the observations of PG1553+113 during the first ∼ 200days of Fermi Gamma-ray Space Telescope science operations, from 2008 August 4 to 2009 February 22 (MJD 54682.7-54884.2). This is the first detailed study of PG1553+113 in the GeV gamma-ray regime and it allows us to fill a gap of three decades in energy in its spectral energy distribution (SED). We find PG1553+113 to be a steady source with a hard spectrum that is best fit by a simple power law in the Fermi energy band. We combine the Fermi data with archival radio, optical, X-ray, and very high energy (VHE) gamma-ray data to model its broadband SED and find that a simple, one-zone synchrotron self-Compton model provides a reasonable fit. PG1553+113 has the softest VHE spectrum of all sources detected in that regime and, out of those with significant detections across the Fermi energy bandpass so far, the hardest spectrum in that energy regime. Thus, it has the largest spectral break of any gamma-ray source studied to date, which could be due to the absorption of the intrinsic gamma-ray spectrum by the extragalactic background light (EBL). Assuming this to be the case, we selected a model with a low level of EBL and used it to absorb the power-law spectrum from PG1553+113 measured with Fermi (200MeV-157GeV) to find the redshift, which gave the best fit to the measured VHE data (90GeV-1.1TeV) for this parameterization of the EBL. We show that this redshift can be considered an upper limit on the distance to PG1553+113. © 2010. The American Astronomical Society.

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  • Gamma-ray and radio properties of six pulsars detected by the Fermi large area telescope

    P. Weltevrede, A.A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, G. Desvignes, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, P.C.C. Freire, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, E. Hays, G. Hobbs, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Keith, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, R.N. Manchester, M.N. Mazziotta, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, N. Wang, K. Watters, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   708 ( 2 ) 1426 - 1441  2010.01  [Refereed]

     View Summary

    We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models. © 2010. The American Astronomical Society.

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  • The Polarized Gamma-Ray Observer, PoGOLite

    TAKAHASHI Hiromitsu, MATSUOKA Masayuki, UMEKI Yudai, YOSHIDA Hiroaki, TANAKA Takuya, MIZUNO Tsunefumi, FUKAZAWA Yasushi, KAMAE Tuneyoshi, MADEJSKI Grzegorz, TAJIMA Hiroyasu, KISS Mózsi, KLAMRA Wlodzimierz, LARSSON Stefan, BETTOLO Cecilia MARINI, PEARCE Mark, RYDE Felix, RYDSTRÖM Stefan, KURITA Kohei, KANAI Yoshikazu, ARIMOTO Makoto, UENO Masaru, KATAOKA Jun, KAWAI Nobuyuki, AXELSSON Magnus, HJALMARSDOTTER Linnea, BOGAERT Gilles, GUNJI Shuichi, KATSUTA Jun'ichiro, TAKAHASHI Tadayuki, VARNER Gary, YUASA Takayuki

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN   8 ( 27 ) Pm_1 - Pm_5  2010

     View Summary

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy-range 25–80 keV. During a beam test at KEK-PF in 2008, 19 detector units and one anti-coincidence detector were assembled, and a 50 keV X-ray beam with a polarization degree of ∼90% was irradiated at the center unit. Signals from all 20 units were fed into flight-version electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 detectors, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be ∼34%. These results confirmed the capabilities of the data-acquisition system for a "pathfinder" flight planned in 2010.

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  • Soft Gamma-ray Detector for the ASTRO-H Mission

    Hiroyasu Tajima, Roger Blandford, Teruaki Enoto, Yasushi Fukazawa, Kirk Gilmore, Tuneyoshi Kamae, Jun Kataoka, Madoka Kawaharada, Motohide Kokubun, Philippe Laurent, Francois Lebrun, Olivier Limousin, Greg Madejski, Kazuo Makishima, Tsunefumi Mizuno, Kazuhiro Nakazawa, Masanori Ohno, Masayuki Ohta, Goro Sato, Rie Sato, Hiromitsu Takahashi, Tadayuki Takahashi, Takaaki Tanaka, Makoto Tashiro, Yukikatsu Terada, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Daisuke Yonetoku

    SPACE TELESCOPES AND INSTRUMENTATION 2010: ULTRAVIOLET TO GAMMA RAY   7732  2010  [Refereed]

     View Summary

    ASTRO-H is the next generation JAXA X-ray satellite, intended to carry instruments with broad energy coverage and exquisite energy resolution. The Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature wide energy band (40-600 keV) at a background level 10 times better than the current instruments on orbit. SGD is complimentary to ASTRO-H's Hard X-ray Imager covering the energy range of 5-80 keV. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield where Compton kinematics is utilized to reject backgrounds. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is afforded by semiconductor sensors, and it results in good background rejection capability due to better constraints on Compton kinematics. Utilization of Compton kinematics also makes the SGD sensitive to the gamma-ray polarization, opening up a new window to study properties of gamma-ray emission processes. The ASTRO-H mission is approved by ISAS/JAXA to proceed to a detailed design phase with an expected launch in 2014. In this paper, we present science drivers and concept of the SGD instrument followed by detailed description of the instrument and expected performance.

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  • Swift and fermi observations of the early afterglow of the short gamma-ray burst 090510

    M. De Pasquale, P. Schady, N. P.M. Kuin, M. J. Page, P. A. Curran, S. Zane, S. R. Oates, S. T. Holland, A. A. Breeveld, E. A. Hoversten, G. Chincarini, D. Grupe, A. A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. Bissaldi, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. S. Briggs, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, C. D. Dermer, A. De Angelis, F. De Palma, B. L. Dingus, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, G. Fishman, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. Granot, J. Greiner, I. A. Grenier, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, M. S. Jackson, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, R. M. Kippen, J. Knödlseder, D. Kocevski, M. Kuss

    Astrophysical Journal Letters   709 ( 2 PART 2 )  2010

     View Summary

    We present the observations of GRB090510 performed by the Fermi Gamma-Ray Space Telescope and the Swift observatory. This is a bright, short burst that shows an extended emission detected in the GeV range. Furthermore, its optical emission initially rises, a feature so far observed only in long bursts, while the X-ray flux shows an initial shallow decrease, followed by a steeper decay. This exceptional behavior enables us to investigate the physical properties of the gamma-ray burst outflow, poorly known in short bursts. We discuss internal and external shock models for the broadband energy emission of this object. © 2010. The American Astronomical Society. All rights reserved..

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  • Discovery of very high energy gamma rays from PKS 1424+240 and multiwavelength constraints on ITS redshift

    V. A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Bautista, M. Beilicke, W. Benbow, M. Böttcher, D. Boltuch, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, Y. C. Chow, L. Ciupik, P. Cogan, W. Cui, C. Duke, A. Falcone, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, G. H. Gillanders, S. Godambe, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C. M. Hui, T. B. Humensky, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. Lebohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, J. Millis, P. Moriarty, T. Nagai, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, A. Pichel, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, M. Schroedter, G. H. Sembroski, G. Demet Senturk, A. W. Smith, D. Steele, S. P. Swordy, M. Theiling, S. Thibadeau, A. Varlotta, V. V. Vassiliev, S. Vincent, R. G. Wagner, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, S. Wissel, M. Wood, B. Zitzer, A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland

    Astrophysical Journal Letters   708 ( 2 PART 2 )  2010

     View Summary

    We report the first detection of very high energy83Gamma-ray emission above 100 GeV. (VHE) gamma-ray emission above 140 GeV from PKS1424+240, a BL Lac object with an unknown redshift. The photon spectrum above 140 GeV measured by VERITAS is well described by a power law with a photon index of 3.8 0.5stat 0.3syst and a flux normalization at 200 GeV of (5.1 0.9stat 0.5syst) × 10-11 TeV -1 cm-2 s-1, where stat and syst denote the statistical and systematical uncertainties, respectively. The VHE flux is steady over the observation period between MJD 54881 and 55003 (from 2009 February 19 to June 21). Flux variability is also not observed in contemporaneous high-energy observations with the Fermi Large Area Telescope. Contemporaneous X-ray and optical data were also obtained from the Swift XRT and MDM observatory, respectively. The broadband spectral energy distribution is well described by a one-zone synchrotron self-Compton model favoring a redshift of less than 0.1. Using the photon index measured with Fermi in combination with recent extragalactic background light absorption models it can be concluded from the VERITAS data that the redshift of PKS 1424+240 is less than 0.66. © 2010. The American Astronomical Society. All rights reserved.

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  • Observations of the large magellanic cloud with fermi

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Dige, E. Do Couto E Silva, P. S. Drel, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, M. S. Jackson, P. Jean, G. Jóhannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev

    Astronomy and Astrophysics   512 ( 13 )  2010

     View Summary

    Context.The Large Magellanic Cloud (LMC) is to date the only normal external galaxy that has been detected in high-energy gamma rays. Highenergy gamma rays trace particle acceleration processes and gamma-ray observations allow the nature and sites of acceleration to be studied. Aims.We characterise the distribution and sources of cosmic rays in the LMC from analysis of gamma-ray observations. Methods.We analyse 11 months of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope and compare it to tracers of the interstellar medium and models of the gamma-ray sources in the LMC. Results.The LMC is detected at 33s significance. The integrated >100 MeV photon flux of the LMC amounts to (2.6 ± 0.2) × 10-7 ph cm-2 s-1 which corresponds to an energy flux of (1.6 ± 0.1) × 10-10 erg cm -2 s-1, with additional systematic uncertainties of < 16%. The analysis reveals the massive star forming region 30 Doradus as a bright source of gamma-ray emission in the LMC in addition to fainter emission regions found in the northern part of the galaxy. The gamma-ray emission from the LMC shows very little correlation with gas density and is rather correlated to tracers of massive star forming regions. The close confinement of gamma-ray emission to star forming regions suggests a relatively short GeV cosmic-ray proton diffusion length. Conclusions. The close correlation between cosmic-ray density and massive star tracers supports the idea that cosmic rays are accelerated in massive star forming regions as a result of the large amounts of kinetic energy that are input by the stellar winds and supernova explosions of massive stars into the interstellar medium. © ESO 2010.

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  • The discovery of γ-ray emission from the blazar RGBJ0710+591

    V. A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Bautista, M. Beilicke, W. Benbow, M. Böttcher, D. Boltuch, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, L. Ciupik, W. Cui, R. Dickherber, C. Duke, A. Falcone, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, G. H. Gillanders, S. Godambe, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, A. Lamerato, S. Lebohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, P. Moriarty, R. Mukherjee, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, D. Petry, A. Pichel, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, P. Roustazadeh, M. Schroedter, G. H. Sembroski, G. Demet Senturk, A. W. Smith, D. Steele, S. P. Swordy, G. Tešić, M. Theiling, S. Thibadeau, A. Varlotta, V. V. Vassiliev, S. Vincent, R. G. Wagner, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, S. Wissel, M. Wood, B. Zitzer, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford

    Astrophysical Journal Letters   715 ( 1 PART 2 )  2010

     View Summary

    The high-frequency-peaked BL Lacertae object RGBJ0710+591 was observed in the very high-energy (VHE; E > 100GeV) wave band by the VERITAS array of atmospheric Cherenkov telescopes. The observations, taken between 2008 December and 2009 March and totaling 22.1 hr, yield the discovery of VHE gamma rays from the source. RGBJ0710+591 is detected at a statistical significance of 5.5 standard deviations (5.5σ) above the background, corresponding to an integral flux of (3.9 ± 0.8) × 10-12 cm-2 s-1 (3% of the Crab Nebula's flux) above 300GeV. The observed spectrum can be fit by a power law from 0.31 to 4.6TeV with a photon spectral index of 2.69 ± 0.26stat ± 0.20sys. These data are complemented by contemporaneous multiwavelength data from the Fermi Large Area Telescope, the Swift X-ray Telescope, the Swift Ultra-Violet and Optical Telescope, and the Michigan-Dartmouth-MIT observatory. Modeling the broadband spectral energy distribution (SED) with an equilibrium synchrotron self-Compton model yields a good statistical fit to the data. The addition of an external-Compton component to the model does not improve the fit nor brings the system closer to equipartition. The combined Fermi and VERITAS data constrain the properties of the high-energy emission component of the source over 4 orders of magnitude and give measurements of the rising and falling sections of the SED. © 2010 The American Astronomical Society. All rights reserved.

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  • X-ray-emitting GHz-peaked-spectrum galaxies: Testing a dynamical-radiative model with broadband spectra

    L. Ostorero, R. Moderski, Stawarz, A. Diaferio, I. Kowalska, C. C. Cheung, J. Kataoka, M. C. Begelman, S. J. Wagner

    Astrophysical Journal   715 ( 2 ) 1071 - 1093  2010

     View Summary

    In a dynamical-radiative model we recently developed to describe the physics of compact, GHz-peaked-spectrum (GPS) sources, the relativistic jets propagate across the inner, kpc-sized region of the host galaxy, while the electron population of the expanding lobes evolves and emits synchrotron and inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the expanding lobes, and photoionized by the active nucleus, are responsible for the radio spectral turnover through free-free absorption (FFA) of the synchrotron photons. The model provides a description of the evolution of the spectral energy distribution (SED) of GPS sources with their expansion, predicting significant and complex high-energy emission, from the X-ray to the γ-ray frequency domain. Here, we test this model with the broadband SEDs of a sample of 11 X-ray-emitting GPS galaxies with compact-symmetric-object morphology, and show that (1) the shape of the radio continuum at frequencies lower than the spectral turnover is indeed well accounted for by the FFA mechanism and (2) the observed X-ray spectra can be interpreted as non-thermal radiation produced via IC scattering of the local radiation fields off the lobe particles, providing a viable alternative to the thermal, accretion-disk-dominated scenario. We also show that the relation between the hydrogen column densities derived from the X-ray (N H) and radio (N HI) data of the sources is suggestive of a positive correlation, which, if confirmed by future observations, would provide further support to our scenario of high-energy emitting lobes. © 2010. The American Astronomical Society. All rights reserved.

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  • Constraints on cosmological dark matter annihilation from the Fermi-LAT isotropic diffuse gamma-ray measurement

    A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. E. Grove, L. Guillemot, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, D. Horan, R. E. Hughes, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris

    Journal of Cosmology and Astroparticle Physics   2010 ( 4 )  2010

     View Summary

    The first published Fermi large area telescope (Fermi-LAT) measurement of the isotropic diffuse gamma-ray emission is in good agreement with a single power law, and is not showing any signature of a dominant contribution from dark matter sources in the energy range from 20 to 100 GeV. We use the absolute size and spectral shape of this measured flux to derive cross section limits on three types of generic dark matter candidates: annihilating into quarks, charged leptons and monochromatic photons. Predicted gamma-ray fluxes from annihilating dark matter are strongly affected by the underlying distribution of dark matter, and by using different available results of matter structure formation we assess these uncertainties. We also quantify how the dark matter constraints depend on the assumed conventional backgrounds and on the Universe's transparency to high-energy gamma-rays. In reasonable background and dark matter structure scenarios (but not in all scenarios we consider) it is possible to exclude models proposed to explain the excess of electrons and positrons measured by the Fermi-LAT and PAMELA experiments. Derived limits also start to probe cross sections expected from thermally produced relics (e.g. in minimal supersymmetry models) annihilating predominantly into quarks. For the monochromatic gamma-ray signature, the current measurement constrains only dark matter scenarios with very strong signals. © 2010 IOP Publishing Ltd and SISSA.

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  • Constraints on dark matter annihilation in clusters of galaxies with the Fermi large area telescope

    M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, A. D. Angelis, F. De Palma, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S. J. Fegan, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, M. Gustafsson, A. K. Harding, M. Hayashida, D. Horan, R. E. Hughes, T. E. Jeltema, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando

    Journal of Cosmology and Astroparticle Physics   2010 ( 5 )  2010

     View Summary

    Nearby clusters and groups of galaxies are potentially bright sources of high-energy gamma-ray emission resulting from the pair-annihilation of dark matter particles. However, no significant gamma-ray emission has been detected so far from clusters in the first 11 months of observations with the Fermi Large Area Telescope. We interpret this non-detection in terms of constraints on dark matter particle properties. In particular for leptonic annihilation final states and particle masses greater than ∼ 200 GeV, gamma-ray emission from inverse Compton scattering of CMB photons is expected to dominate the dark matter annihilation signal from clusters, and our gamma-ray limits exclude large regions of the parameter space that would give a good fit to the recent anomalous Pamela and Fermi-LAT electron-positron measurements. We also present constraints on the annihilation of more standard dark matter candidates, such as the lightest neutralino of supersymmetric models. The constraints are particularly strong when including the fact that clusters are known to contain substructure at least on galaxy scales, increasing the expected gamma-ray flux by a factor of ∼ 5 over a smooth-halo assumption. We also explore the effect of uncertainties in cluster dark matter density profiles, finding a systematic uncertainty in the constraints of roughly a factor of two, but similar overall conclusions. In this work, we focus on deriving limits on dark matter models; a more general consideration of the Fermi-LAT data on clusters and clusters as gamma-ray sources is forthcoming. © 2010 IOP Publishing Ltd and SISSA.

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  • In-orbit performance of avalanche photodiode as radiation detector on-board a pico-satellite Cute-1.7+APD II

    T. Toizumi, Y. Yatsu, T. Nakamori, J. Kataoka, Y. Tsubuku, Y. Kuramoto, T. Enomoto, R. Usui, N. Kawai, K. Akiyama, S. Inagawa, H. Ashida, K. Omagari, N. Miyashita, S. Matsunaga, Y. Ishikawa, Y. Matsunaga, N. Kawabata

    HIGH ENERGY, OPTICAL, AND INFRARED DETECTORS FOR ASTRONOMY IV   7742  2010  [Refereed]

     View Summary

    Cute-1.7+APD II is the third pico-satellite developed by students at the Tokyo Institute of Technology. One of the primary goals of the mission is to validate the use of avalanche photodiodes (APDs) as a radiation detector for the first time in a space experiment. The satellite was successfully launched by an ISRO PSLV-C9 rocket in Apr 2008 and has since been in operation for more than 20 months. Cute-1.7+APD II carries two reverse-type APDs to monitor the distribution of low energy particles down to 9.2 keV trapped in a Low Earth Orbit (LEO), including South Atlantic Anomaly (SAA) as well as aurora bands. We present the design parameters and various preflight tests of the APDs prior to launch, particularly, the high counting response and active gain control system for the Cute-1.7+APD II mission. Examples of electron/proton distribution, obtained in continuous 12-hour observations, will be presented to demonstrate the initial flight performance of the APDs in orbit.

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  • A Thermal-Neutron Detector with a Phoswich System of LiCaAlF6 and BGO Crystal Scintillators onboard PoGOLite

    Takahashi H, Yonetani M, Matsuoka M, Mizuno T, Fukazawa Y, Yanagida T, Fujimoto Y, Yokota Y, Yoshikawa A, Kawaguchi N, Ishizu S, Fukuda K, Suyama T, Watanabe K, Tajima H, Kanai Y, Kawai N, Kataoka J, Katsuta J, Takahashi T, Gunji S, Axelsson M, Jackson M, Kiss M, Klamra W, Kole M, Larsson S, Mallol P, Pearce M, Ryde F, Rydstrom S, Olofsson G, Floren H-G, Kamae T, Madejski G, Varner G, IEEE

    2010 Ieee Nuclear Science Symposium Conference Record (Nss/mic)     32 - 37  2010  [Refereed]

  • Development of BGO active shield for the ASTRO-H soft Gamma-ray Detector

    Hanabata Y, Fukazawa Y, Yamaoka K, Tajima H, Kataoka J, Nakazawa K, Takahashi H, Mizuno T, Ohno M, Kokubun M, Takahashi T, Watanabe S, Tashiro M, Terada Y, Sasaki C, Nakajima K, Mizushima T

    Proceedings of SPIE - The International Society for Optical Engineering   7732  2010  [Refereed]

     View Summary

    Soft Gamma-ray Detector (SGD:40-600 keV) will be mounted on the 6th Japanese X-ray observatory ASTRO-H to be launched in 2014. The main part of the SGD is a Compton camera with a narrow field of view and surrounded by BGO active shields (SGD-BGO). Via this combination, the SGD can achieve sensitivity more than ten times superior to the Suzaku/HXD. The BGO active shield will also function as a gamma-ray burst monitor as proven by the wide-band all-sky monitor (WAM) of the Suzaku/HXD. Avalanche Photodiodes (APDs) are used to read out scintillation lights from the BGO. The size of the former also means we need to focus on collecting light from large, complex-shaped BGO blocks. The significant leakage current of the APD means a lower temperature is preferred to minimize the noise while a higher temperature is preferred to simplify the cooling system. To optimize the BGO shape and the operating temperature, we tested the performance of the BGO readout system with various BGO shapes under different operating temperatures. We also apply waveform sampling by flash-ADC and digital filter instead of a conventional analog filter and ADC scheme to reduce the space and power of the circuit with increased flexibilities. As an active shield, we need to achieve a threshold level of 50-100 keV. Here, we report on the studies of threshold energy of active shield under various conditions and signal processings. © 2010 SPIE.

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  • Hard X-ray and gamma-ray detector for ASTRO-H based on Si and CdTe imaging sensors

    Kokubun M, Watanabe S, Nakazawa K, Tajima H, Fukazawa Y, Takahashi T, Kataoka J, Kamae T, Katagiri H, Madejski G.M, Makishima K, Mizuno T, Ohno M, Sato R, Takahashi H, Tanaka T, Tashiro M, Terada Y, Yamaoka K

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   623 ( 1 ) 425 - 427  2010  [Refereed]

     View Summary

    We have been developing a hard X-ray imager and soft gamma-ray detector as on board instruments of the ASTRO-H mission. The Hard X-ray Imager (HXI) is one of the three focal plane detectors of ASTRO-H, which is aimed to realize the focusing imaging of hard X-ray photons in combination with hard X-ray telescopes. By use of the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride strip detector, it fully covers the energy range up to 80 keV with a high quantum efficiency. High spatial resolutions of 250μm pitch and energy resolutions of 12 keV (FWMH) are at the same time achieved with low noise front-end ASICs. The Soft Gamma-ray Detector (SGD) is a novel and unique detector which is characterized by semiconductor Compton cameras surrounded by narrow field-of-view active shields, and covers a higher energy range (30600 keV) than that of HXI. It consists of four Compton Cameras constructed with many layers of Silicon and CdTe pad detectors. With its multi-layer structure and Compton reconstruction capability, in addition to the BGO active shields read by Avalanche photo-diodes, this detector will achieve an extremely high background rejection efficiency in the orbit. We report the current status of hardware development including the design requirement, expected performance, and technical readinesses of key technologies. © 2010 Elsevier B.V. All rights reserved.

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  • Fermi large area telescope observations of the cosmic-ray induced γ-ray emission of the Earth's atmosphere

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, E. Hays, D. Horan, R. E. Hughes, G. Jóhannesson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris

    Physical Review D - Particles, Fields, Gravitation and Cosmology   80 ( 12 )  2009.12

     View Summary

    We report on measurements of the cosmic-ray induced γ-ray emission of Earth's atmosphere by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The Large Area Telescope has observed the Earth during its commissioning phase and with a dedicated Earth limb following observation in September 2008. These measurements yielded ∼6.4×106 photons with energies >100MeV and ∼250 hours total live time for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission-often referred to as Earth albedo gamma-ray emission-has a power-law shape up to 500GeV with spectral index Γ=2.79±0.06. © 2009 The American Physical Society.

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  • Fermi observations of TeV-Selected active galactic nuclei

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, G. Di Bernardo, E. Do Couto E Silva, P.S. Drell, A. Drlica-Wagner, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, L. Foschini, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.C. Reyes, S. Ritz, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, T.L. Schalk, A. Sellerholm, C. Sgrò, M.S. Shaw, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, Y. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   707 ( 2 ) 1310 - 1333  2009.12  [Refereed]

     View Summary

    We report on observations of TeV-selected active galactic nuclei (AGNs) made during the first 5.5 months of observations with the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope (Fermi). In total, 96 AGNs were selected for study, each being either (1) a source detected at TeV energies (28 sources) or (2) an object that has been studied with TeV instruments and for which an upper limit has been reported (68 objects). The Fermi observations show clear detections of 38 of these TeV-selected objects, of which 21 are joint GeV-TeV sources, and 29 were not in the third EGRET catalog. For each of the 38 Fermi-detected sources, spectra and light curves are presented. Most can be described with a power law of spectral index harder than 2.0, with a spectral break generally required to accommodate the TeV measurements. Based on an extrapolation of the Fermi spectrum, we identify sources, not previously detected at TeV energies, which are promising targets for TeV instruments. Evidence for systematic evolution of the γ-ray spectrum with redshift is presented and discussed in the context of interaction with the extragalactic background light. © 2009 The American Astronomical Society.

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  • Fermi large area telescope measurements of the diffuse gamma-ray emission at intermediate galactic latitudes

    A. A. Abdo, M. Ackermann, M. Ajello, B. Anderson, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, H. Dereli, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, G. Di Bernardo, M. Dormody, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. L. Kocian, F. Kuehn, M. Kuss, J. Lande, L. Latronico, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, W. McConville

    Physical Review Letters   103 ( 25 )  2009.12

     View Summary

    The diffuse galactic γ-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess γ-ray emission 1GeV relative to diffuse galactic γ-ray emission models consistent with directly measured CR spectra (the so-called "EGRET GeV excess"). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse γ-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10°≤|b|≤20°. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic γ-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess. © 2009 The American Physical Society.

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  • Fermi large area telescope gamma-ray detection of the radio galaxy m87

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, A. Cannon, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, D.S. Davis, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, D. Donato, E.D. Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, G.B. Taylor, J.B. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler, D.E. Harris, F. Massaro, L. Stawarz

    Astrophysical Journal Letters   707 ( 1 ) 55 - 60  2009.12  [Refereed]

     View Summary

    We report the Fermi Large Area Telescope (LAT) discovery of high-energy (MeV/GeV) γ-ray emission positionally consistent with the center of the radio galaxy M87, at a source significance of over 10σ in 10 months of all-sky survey data. Following the detections of Cen A and Per A, this makes M87 the third radio galaxy seen with the LAT. The faint point-like γ-ray source has a >100 MeV flux of 2.45 (?± 0.63) × 10-8 photons cm-2 s-1 (photon index = 2.26 ± 0.13) with no significant variability detected within the LAT observation. This flux is comparable with the previous EGRET upper limit (<2.18 × 10-8 photons cm-2 s-1, 2σ), thus there is no evidence for a significant MeV/GeV flare on decade timescales. Contemporaneous Chandra and Very Long Baseline Array data indicate low activity in the unresolved X-ray and radio core relative to previous observations, suggesting M87 is in a quiescent overall level over the first year of Fermi-LAT observations. The LAT γ-ray spectrum is modeled as synchrotron self-Compton (SSC) emission from the electron population producing the radio-to-X-ray emission in the core. The resultant SSC spectrum extrapolates smoothly from the LAT band to the historical-minimum TeV emission. Alternative models for the core and possible contributions from the kiloparsec-scale jet in M87 are considered, and cannot be excluded. © 2009. The American Astronomical Society. All rights reserved.

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  • Multiwavelength monitoring of the enigmatic narrow-line seyfert 1 PMN J0948+0022 in 2009 march-july

    A.A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, A. Celotti, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, W. Collmar, J. Conrad, L. Costamante, S. Cutini, A. De Angelis, F. De Palma, E. Do Couto E Silva, P.S. Drell, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, W.N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, W. McConville, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, I. Nestoras, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pavlidou, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, O. Reimer, T. Reposeur, J.L. Richards, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, G. Tagliaferri, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, A.E. Wehrle, B.L. Winer, K.S. Wood, T. Ylinen, J.A. Zensus, M. Ziegler, E. Angelakis, C. Bailyn, H. Bignall, J. Blanchard, E.W. Bonning, M. Buxton, R. Canterna, A. Carramĩana, L. Carrasco, F. Colomer, A. Doi, G. Ghisellini, M. Hauser, X. Hong, J. Isler, M. Kino, Y.Y. Kovalev, Y.A. Kovalev, T.P. Krichbaum, A. Kutyrev, A. Lahteenmaki, H.J. Van Langevelde, M.L. Lister, D. MacOmb, L. Maraschi, N. Marchili, H. Nagai, Z. Paragi, C. Phillips, A.B. Pushkarev, E. Recillas, P. Roming, M. Sekido, M.A. Stark, A. Szomoru, J. Tammi, F. Tavecchio, M. Tornikoski, A.K. Tzioumis, C.M. Urry, S. Wagner

    Astrophysical Journal Letters   707 ( 1 ) 727 - 737  2009.12  [Refereed]

     View Summary

    Following the recent discovery of γ rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to γ rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to γ-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the γ-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars. © 2009 The American Astronomical Society.

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  • Fermi observations of high-energy gamma-ray emission from GRB 080825c

    A.A. Abdo, M. Ackermann, K. Asano, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, D.L. Band, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, V. Chaplin, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, V. Connaughton, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W.B. Focke, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, L. Gibby, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, A. Goldstein, J. Granot, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, D. Kocevski, N. Komin, C. Kouveliotou, F. Kuehn, M. Kuss, L. Latronico, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, S. McBreen, J.E. McEnery, S. McGlynn, C. Meegan, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, W.S. Paciesas, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, R. Preece, S. Rainò, R. Rando, M. Razzano, S. Razzaque, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   707 ( 1 ) 580 - 592  2009.12  [Refereed]

     View Summary

    The Fermi Gamma-ray Space Telescope has opened a new high-energy window in the study of gamma-ray bursts (GRBs). Here we present a thorough analysis of GRB 080825C, which triggered the Fermi Gamma-ray Burst Monitor (GBM), and was the first firm detection of a GRB by the Fermi Large Area Telescope (LAT). We discuss the LAT event selections, background estimation, significance calculations, and localization for Fermi GRBs in general and GRB 080825C in particular. We show the results of temporal and time-resolved spectral analysis of the GBM and LAT data. We also present some theoretical interpretation of GRB 080825C observations as well as some common features observed in other LAT GRBs. © 2009. The American Astronomical Society. All rights reserved.

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  • Pr:Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (LuAG) scintillator read-out using UV-enhanced avalanche photodiode

    Kei Kamada, Takayuki Yanagida, Jun Kataoka, Akira Yoshikawa, Akihiro Fukabori, Kousuke Tsutsumi, Takanori Endo, Yoshiyuki Usuki

    IEEE Nuclear Science Symposium Conference Record     1949 - 1951  2009.12  [Refereed]

     View Summary

    In this work, energy resolution of Pr:LuAG scintillator was investigated using PMT (Hamamatsu, R7600U), conventional Si-APD (Hamamatsu, S8664-8222) and UV-enhanced Si-APD (Hamamatsu, S8664-8223) at 20 °C hy 662keV gamma-ray irradiation. The APD S8664-8223 has better quantum efficiency (QE) of 45.8% around 310nm of Pr:LuAG emission wavelength than that of S8664-8222 (QE=4.6%@310nm) and R7600U (QE=21%@310nm). Using UV-enhanced APD S8664-8223, Pr:LuAG sample with 2.15 x 2.15 x 10 mm size showed the best energy resolution of 5.7%@662keV at M=10.7. ©2009 IEEE.

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  • Fermi large area telescope detection of pulsed γ-rays from the vela-like pulsars PSR J1048-5832 and PSR J2229+6114

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, J. Conrad, A. De Angelis, F. De Palma, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, J. Halpern, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, G. Hobbs, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, Y. Uchiyama, T.L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, N. Wang, K. Watters, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   706 ( 2 ) 1331 - 1340  2009.12  [Refereed]

     View Summary

    We report the detection of γ-ray pulsations (≥0.1 GeV) from PSR J2229+6114 and PSR J1048-5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the γ-ray band were acquired by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, while the radio rotational ephemerides used to fold the γ-ray light curves were obtained using the Green Bank Telescope, the Lovell telescope at Jodrell Bank, and the Parkes Telescope. The two young radio pulsars, located within the error circles of the previously unidentified EGRET sources 3EG J1048-5840 and 3EG J2227+6122, present spin-down characteristics similar to the Vela pulsar. PSR J1048-5832 shows two sharp peaks at phases 0.15 ± 0.01 and 0.57 ± 0.01 relative to the radio pulse confirming the EGRET light curve, while PSR J2229+6114 presents a very broad peak at phase 0.49 0.01. The γ-ray spectra above 0.1 GeV of both pulsars are fit with power laws having exponential cutoffs near 3 GeV, leading to integral photon fluxes of (2.19 ± 0.22 ± 0.32) × 10-7 cm-2 s-1 for PSR J1048-5832 and (3.77 ± 0.22 ± 0.44) × 10-7 cm-2 s-1 for PSR J2229+6114. The first uncertainty is statistical and the second is systematic. PSR J1048-5832 is one of the two LAT sources which were entangled together as 3EG J1048-5840. These detections add to the growing number of young γ-ray pulsars that make up the dominant population of GeV γ-ray sources in the Galactic plane. © 2009. The American Astronomical Society.

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  • Fermi observations of GRB 090902b: A distinct spectral component in the prompt and delayed emission

    A.A. Abdo, M. Ackermann, M. Ajello, K. Asano, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, J.M. Burgess, D.N. Burrows, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, V. Connaughton, J. Conrad, S. Cutini, V. D'Elia, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, B.L. Dingus, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, G. Fishman, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, A. Goldstein, J. Granot, J. Greiner, I.A. Grenier, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, D. Horan, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, R.M. Kippen, J. Knödlseder, D. Kocevski, N. Komin, C. Kouveliotou, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, S. McBreen, J.E. McEnery, S. McGlynn, C. Meegan, P. Mészros, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, W.S. Paciesas, D. Paneque, J.H. Panetta, V. Pelassa, M. Pepe, M. Pesce-Rollins, V. Petrosian, F. Piron, T.A. Porter, R. Preece, S. Rainò, R. Rando, A. Rau, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, P.W.A. Roming, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, P.D. Smith, P. Spinelli, M. Stamatikos, F.W. Stecker, G. Stratta, M.S. Strickman, D.J. Suson, C.A. Swenson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. Uehara, T.L. Usher, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, R. Yamazaki, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   706 ( 1 ) L138 - L144  2009.11  [Refereed]

     View Summary

    We report on the observation of the bright, long gamma-ray burst (GRB), GRB 090902B, by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments on-board the Fermi observatory. This was one of the brightest GRBs to have been observed by the LAT, which detected several hundred photons during the prompt phase. With a redshift of z = 1.822, this burst is among the most luminous detected by Fermi. Time-resolved spectral analysis reveals a significant power-law component in the LAT data that is distinct from the usual Band model emission that is seen in the sub-MeV energy range. This power-law component appears to extrapolate from the GeV range to the lowest energies and is more intense than the Band component, both below ∼ 50 keV and above 100 MeV. The Band component undergoes substantial spectral evolution over the entire course of the burst, while the photon index of the power-law component remains constant for most of the prompt phase, then hardens significantly toward the end. After the prompt phase, power-law emission persists in the LAT data as late as 1 ks post-trigger, with its flux declining as t -1.5. The LAT detected a photon with the highest energy so far measured from a GRB, 33.4 +2.7-3.5 GeV. This event arrived 82 s after the GBM trigger and ∼ 50 s after the prompt phase emission had ended in the GBM band. We discuss the implications of these results for models of GRB emission and for constraints on models of the extragalactic background light. © 2009. The American Astronomical Society.

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  • Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C

    A.A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, M.S. Jackson, G. Jóhannesson, A.S. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Katsuta, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A. Makeev, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, R. Yamazaki, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   706 ( 1 ) L1 - L6  2009.11  [Refereed]

     View Summary

    The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (104 yr) ∼ with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 × 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral π mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to ̄n H Wp ≃ 5× 1051 (D/6kpc)2 erg cm-2. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays. © 2009. The American Astronomical Society. All rights reserved.

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  • A limit on the variation of the speed of light arising from quantum gravity effects

    A.A. Abdo, M. Ackermann, M. Ajello, K. Asano, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechto, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, E.D. Bloom, E. Bonamente, J. Bonnell, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M.S. Briggs, M. Brigida, P. Bruel, J.M. Burgess, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, V. Chaplin, E. Charles, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, V. Connaughton, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Dige, B.L. Dingus, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, J. Finke, G. Fishman, W.B. Focke, L. Foschini, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, L. Gibby, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. Granot, J. Greiner, I.A. Grenier, M.-H. Grondin, J.E. Grove, D. Grupe, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, E.A. Hoversten, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, R.M. Kippen, J. Knödlseder, D. Kocevski, C. Kouveliotou, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M.N. Mazziotta, S. McBreen, J.E. McEnery, S. McGlynn, P. Mészáros, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, W.S. Paciesas, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, V. Petrosian, F. Piron, T.A. Porter, R. Preece, S. Rainò, E. Ramirez-Ruiz, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, M. Roth, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. SazParkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, F.W. Stecker, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, K. Toma, D.F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T. Uehara, T.L. Usher, A.J. Van, Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. VonKienlin, A.P. Waite, P. Wang, C. Wilson-Hodge, B.L. Winer, K.S. Wood, X.F. Wu, R. Yamazaki, T. Ylinen, M. Ziegler

    Nature   462 ( 7271 ) 331 - 334  2009.11  [Refereed]

     View Summary

    A cornerstone of Einsteinĝ€™s special relativity is Lorentz invarianceĝ€"the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck)1.62×10-33cm or E(Planck) ≤ M(Planck)c 21.22×1019GeV), at which quantum effects are expected to strongly affect the nature of spaceĝ€"time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in-ray burst (GRB) light-curves. Here we report the detection of emission up to 31GeV from the distant and short GRB090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of spaceĝ€"time on a very small scale linearly alters the speed of light. © 2009 Macmillan Publishers Limited. All rights reserved.

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  • The on-orbit calibration of the Fermi Large Area Telescope

    A.A. Abdo, M. Ackermann, M. Ajello, J. Ampe, B. Anderson, W.B. Atwood, M. Axelsson, R. Bagagli, L. Baldini, J. Ballet, G. Barbiellini, J. Bartelt, D. Bastieri, B.M. Baughman, K. Bechtol, D. Bédérède, F. Bellardi, R. Bellazzini, F. Belli, B. Berenji, D. Bisello, E. Bissaldi, E.D. Bloom, G. Bogaert, J.R. Bogart, E. Bonamente, A.W. Borgland, P. Bourgeois, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G. Busetto, G.A. Caliandro, R.A. Cameron, M. Campell, P.A. Caraveo, S. Carius, P. Carlson, J.M. Casandjian, E. Cavazzuti, M. Ceccanti, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, R. Chipaux, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Condamoor, J. Conrad, R. Corbet, S. Cutini, D.S. Davis, M. DeKlotz, C.D. Dermer, A. de Angelis, F. de Palma, S.W. Digel, P. Dizon, M. Dormody, E. do Couto e Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, D. Fabiani, C. Farnier, C. Favuzzi, E.C. Ferrara, O. Ferreira, Z. Fewtrell, D.L. Flath, P. Fleury, W.B. Focke, K. Fouts, M. Frailis, D. Freytag, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. Goodman, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, M. Hakimi, G. Haller, Y. Hanabata, P.A. Hart, P. Hascall, E. Hays, M. Huffer, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, A. Kavelaars, H. Kelly, M. Kerr, W. Klamra, J. Knödlseder, M.L. Kocian, F. Kuehn, M. Kuss, L. Latronico, C. Lavalley, B. Leas, B. Lee, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, D.K. Lung, G.M. Madejski, A. Makeev, B. Marangelli, M. Marchetti, M.M. Massai, D. May, G. Mazzenga, M.N. Mazziotta, J.E. McEnery, S. McGlynn, C. Meurer, P.F. Michelson, M. Minuti, N. Mirizzi, P. Mitra, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, M. Mongelli, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, D. Nelson, L. Nilsson, S. Nishino, P.L. Nolan, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, A. Paccagnella, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, P. Picozza, M. Pinchera, F. Piron, T.A. Porter, S. Rainò, R. Rando, E. Rapposelli, W. Raynor, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.C. Reyes, S. Ritz, S. Robinson, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, A. Sacchetti, H.F.-W. Sadrozinski, N. Saggini, D. Sanchez, A. Sander, L. Sapozhnikov, O.H. Saxton, P.M. Saz Parkinson, A. Sellerholm, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, T.E. Stephens, M.S. Strickman, A.W. Strong, M. Sugizaki, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, M. Turri, T.L. Usher, N. Vilchez, N. Virmani, V. Vitale, L.L. Wai

    Astroparticle Physics   32 ( 3-4 ) 193 - 219  2009.10  [Refereed]

     View Summary

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009. © 2009 Elsevier B.V.

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  • Fermi lat observations of LS i +61°303: First detection of an orbital modulation in GeV gamma rays

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, Ö. Çelik, E. Charles, S. Chaty, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Corbel, R. Corbet, S. Cutini, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, G. Dubus, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, A.B. Hill, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, F. Kuehn, M. Kuss, J. Lande, S. Larsson, L. Latronico, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, M.N. Mazziotta, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, M.S. Shaw, A. Sierpowska-Bartosik, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, E. Striani, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   701 ( 2 ) L123 - L128  2009.08  [Refereed]

     View Summary

    This Letter presents the first results from the observations of LS I +61°303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 ± 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 ± 0.03(stat) ± 0.07(syst) 10-6 ph cm-2 s -1, with a cutoff at 6.3 ± 1.1(stat) ± 0.4(syst) GeV and photon index Γ = 2.21 ± 0.04(stat) ± 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link between HE and VHE gamma rays is nontrivial. © 2009. The American Astronomical Society.

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  • A population of gamma-ray millisecond pulsars seen with the fermi large area telescope

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, G.F. Bignami, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, P. Carlson, J.M. Casandjian, C. Cecchi, Ö. Çelik, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, R. Corbet, S. Cutini, C.D. Dermer, G. Desvignes, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, S.J. Fegan, W.B. Focke, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, G. Hobbs, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kramer, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, M.A. McLaughlin, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, F. Ryde, H.F.W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, J.L. Starck, E. Striani, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, P. Wang, K. Watters, N. Webb, P. Weltevrede, B.L. Winer, K.S. Wood, T. Ylinen, M. Ziegler

    Science   325 ( 5942 ) 848 - 852  2009.08  [Refereed]

     View Summary

    Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

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  • Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT

    A.A. Abdo, M. Ackermann, M. Ajello, B. Anderson, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, G.F. Bignami, R.D. Blandford, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, Ö. Çelik, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S.J. Fegan, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, C. Gwon, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T.A. Porter, J.R. Primack, S. Rainò, R. Rando, P.S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M. Saz Parkinson, J.D. Scargle, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A.P. Waite, P. Wang, K. Watters, B.L. Winer, M.T. Wolff, K.S. Wood, T. Ylinen, M. Ziegler

    Science   325 ( 5942 ) 840 - 844  2009.08  [Refereed]

     View Summary

    Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants.

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  • Pulsed gamma-rays from PSR j2021+3651 with the Fermi large area telescope

    A.A. Abdo, M. Ackermann, M. Ajello, W.B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, G. Bogaert, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, F. Camilo, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, A.W. Chen, C.C. Cheung, J. Chiang, S. Ciprini, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, P. Demorest, C.D. Dermer, A. De Angelis, A. De Luca, F. De Palma, S.W. Digel, M. Dormody, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, W.B. Focke, M. Frailis, P.C.C. Freire, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, B. Kiziltan, J. Knödlseder, N. Komin, M. Kramer, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, A.G. Lyne, A. Makeev, R.N. Manchester, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, M.A. McLaughlin, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, M. Ozaki, D. Paneque, J.H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, S.M. Ransom, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, P.M.S. Parkinson, C. Sgrò, A. Sierpowska-Bartosik, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, B.W. Stappers, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, S.E. Thorsett, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A.P. Waite, E. Wallace, K. Watters, P. Weltevrede, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   700 ( 2 ) 1059 - 1066  2009.08  [Refereed]

     View Summary

    We report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 ± 0.004±0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56±3±11) × 10-8 cm-2 s-1. The photon spectrum is well described by an exponentially cut-off power law of the form , where the energy E is expressed in GeV. The photon index is Γ = 1.5±0.1±0.1 and the exponential cut-off is Ec = 2.4±0.3±0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524±4 rad m-2 but a poorly constrained magnetic geometry. Re-analysis of Chandra X-ray Observatory data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Gamma-ray emission from the polar cap region seems unlikely for this pulsar. © 2009. The American Astronomical Society. All rights reserved.

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  • Fermi/large area telescope discovery of gamma-ray emission from a relativistic jet in the narrow-line quasar pmn j0948+0022

    A.A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B.M. Baughman, K. Bechtol, R. Bellazzini, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, W. Collmar, J. Conrad, L. Costamante, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, E.D.C.E. Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W.B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, R.C. Hartman, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, W. Max-Moerbeck, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, J.P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, D. Paneque, J.H. Panetta, D. Parent, V. Pavlidou, T.J. Pearson, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, T. Reposeur, J.L. Richards, S. Ritz, A.Y. Rodriguez, R.W. Romani, F. Ryde, H.F.-W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P.M.S. Parkinson, J.D. Scargle, T.L. Schalk, C. Sgrò, D.A. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. Stevenson, M.S. Strickman, D.J. Suson, G. Tagliaferri, H. Takahashi, T. Tanaka, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, N. Vilchez, V. Vitale, A.P. Waite, B.L. Winer, K.S. Wood, T. Ylinen, J.A. Zensus, M. Ziegler, G. Ghisellini, L. Maraschi, F. Tavecchio, E. Angelakis

    Astrophysical Journal Letters   699 ( 2 ) 976 - 984  2009.07  [Refereed]

     View Summary

    We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy γ-ray emission from the peculiar quasar PMN J0948+0022 (z = 0.5846). The optical spectrum of this object exhibits rather narrow Hβ (FWHM(Hβ) 1500 km s-1), weak forbidden lines, and is therefore classified as a narrow-line type I quasar. This class of objects is thought to have relatively small black hole mass and to accrete at a high Eddington ratio. The radio loudness and variability of the compact radio core indicate the presence of a relativistic jet. Quasi-simultaneous radio/optical/X-ray and γ-ray observations are presented. Both radio and γ-ray emissions (observed over five months) are strongly variable. The simultaneous optical and X-ray data from Swift show a blue continuum attributed to the accretion disk and a hard X-ray spectrum attributed to the jet. The resulting broadband spectral energy distribution (SED) and, in particular, the γ-ray spectrum measured by Fermi are similar to those of more powerful Flat-Spectrum Radio Quasars (FSRQs). A comparison of the radio and γ-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and γ-ray power with respect to other FSRQs. The physical parameters obtained from modeling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti & Ghisellini. We suggest that the similarity of the SED of PMN J0948+0022 to that of more massive and more powerful quasars can be understood in a scenario in which the SED properties depend on the Eddington ratio rather than on the absolute power. © 2009. The American Astronomical Society.

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  • Pulsed gamma rays from the millisecond pulsar J0030+0451 with the fermi large area telescope

    A.A. Abdo, M. Ackermann, W.B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B.M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E.D. Bloom, E. Bonamente, A.W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, J.M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L.R. Cominsky, J. Conrad, S. Cutini, C.D. Dermer, A. De Angelis, F. De Palma, S.W. Digel, M. Dormody, E.D.C.E. Silva, P.S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A.K. Harding, M. Hayashida, E. Hays, R.E. Hughes, G. Jóhannesson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M.L. Kocian, N. Komin, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, M. Marelli, M.N. Mazziotta, W. McConville, J.E. McEnery, C. Meurer, P.F. Michelson, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, A. Morselli, I.V. Moskalenko, S. Murgia, P.L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, B. Pancrazi, D. Paneque, J.H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T.A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, F. Ryde, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, P.M.S. Parkinson, C. Sgrò, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M.S. Strickman, D.J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J.B. Thayer, J.G. Thayer, G. Theureau, D.J. Thompson, L. Tibaldo, D.F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T.L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A.P. Waite, K. Watters, N. Webb, K.S. Wood, T. Ylinen, M. Ziegler

    Astrophysical Journal Letters   699 ( 2 ) 1171 - 1177  2009.07  [Refereed]

     View Summary

    We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar (MSP) PSR J0030+0451 with the Large Area Telescope on the Fermi Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second MSP to be detected in gamma rays after PSR J0218+4232, observed by the EGRET instrument on the Compton Gamma-Ray Observatory. The spin-down power erg s-1 is an order of magnitude lower than the empirical lower bound of previously known gamma-ray pulsars. The emission profile is characterized by two narrow peaks, 0.07 0.01 and 0.08 0.02 wide, respectively, separated by 0.44 0.02 in phase. The first gamma-ray peak falls 0.15 0.01 after the main radio peak. The pulse shape is similar to that of the "normal" gamma-ray pulsars. An exponentially cutoff power-law fit of the emission spectrum leads to an integral photon flux above 100 MeV of (6.76 1.05 1.35) × 10-8 cm-2 s-1 with cutoff energy (1.7 0.4 0.5) GeV. Based on its parallax distance of (300 90) pc, we obtain a gamma-ray efficiency for the conversion of spin-down energy rate into gamma-ray radiation, assuming isotropic emission. © 2009. The American Astronomical Society. All rights reserved..

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  • SUZAKU WIDE BAND ANALYSIS OF THE X-RAY VARIABILITY OF TeV BLAZAR Mrk 421 IN 2006

    Masayoshi Ushio, Takaaki Tanaka, Grzegorz Madejski, Tadayuki Takahashi, Masaaki Hayashida, Jun Kataoka, Daniel Mazin, Stefan Ruegamer, Rie Sato, Masahiro Teshima, Stefan Wagner, Yuichi Yaji

    ASTROPHYSICAL JOURNAL   699 ( 2 ) 1964 - 1972  2009.07  [Refereed]

     View Summary

    We present the results of X-ray observations of the well studied TeV blazar Mrk 421 with the Suzaku satellite in 2006 April 28. During the observation, Mrk 421 was undergoing a large flare and the X-ray flux was variable, decreasing by similar to 50%, from 7.8 x 10(-10) to 3.7 x 10(-10) erg s(-1) cm(-2) in about 6 hr, followed by an increase by similar to 35%. Thanks to the broad bandpass coupled with high sensitivity of Suzaku, we measured the evolution of the spectrum over the 0.4-60 keV band in data segments as short as similar to 1 ks. The data show deviations from a simple power-law model, but also a clear spectral variability. The time-resolved spectra are fitted by a synchrotron model, where the observed spectrum is due to a exponentially cutoff power-law distribution of electrons radiating in uniform magnetic field; this model is preferred over a broken power law. As another scenario, we separate the spectrum into "steady" and "variable" components by subtracting the spectrum in the lowest-flux period from those of other data segments. In this context, the difference ("variable") spectra are all well described by a broken power-law model with photon index Gamma similar to 1.6, breaking at energy epsilon(brk) similar or equal to 3 keV to another photon index Gamma similar to 2.1 above the break energy, differing from each other only by normalization, while the spectrum of the "steady" component is best described by the synchrotron model. We suggest that the rapidly variable component is due to relatively localized shock (Fermi I) acceleration, while the slowly variable ("steady") component is due to the superposition of shocks located at larger distance along the jet, or due to other acceleration process, such as the stochastic acceleration on magnetic turbulence (Fermi II) in the more extended region.

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  • FERMI/LARGE AREA TELESCOPE BRIGHT GAMMA-RAY SOURCE LIST

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, G. F. Bignami, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, L. Costamante, S. Cutini, D. S. Davis, C. D. Dermer, A. de Angelis, A. de Luca, F. de Palma, S. W. Digel, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, D. Horan, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, D. Kocevski, M. L. Kocian, N. Komin, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, L. Poupard, S. Raino, R. Rando, P. S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. S. Shaw, C. Shrader, A. Sierpowska-Bartosik, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A. P. Waite, E. Wallace, P. Wang, K. Watters, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   183 ( 1 ) 46 - 66  2009.07  [Refereed]

     View Summary

    Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the gamma-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than similar to 10 sigma) gamma-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) gamma-ray sources in the early mission data.

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  • FERMI DISCOVERY OF GAMMA-RAY EMISSION FROM NGC 1275

    A. A. Abdo, M. Ackermann, M. Ajello, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Celotti, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L. R. Cominsky, J. Conrad, L. Costamante, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, J. Finke, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, Y. Kanai, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, F. Kuehn, M. Kuss, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, R. Sato, P. M. Saz Parkinson, C. Sgro, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. G. Thayer, D. J. Thompson, D. F. Torres, G. Tosti, Y. Uchiyama, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler, H. D. Aller, M. F. Aller, K. I. Kellermann, Y. Y. Kovalev, Yu. A. Kovalev, M. L. Lister, A. B. Pushkarev

    ASTROPHYSICAL JOURNAL   699 ( 1 ) 31 - 39  2009.07  [Refereed]

     View Summary

    We report the discovery of high-energy (E &gt; 100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the Fermi Gamma-ray Space Telescope. The positional center of the gamma-ray source is only approximate to 3' away from the NGC 1275 nucleus, well within the 95% LAT error circle of approximate to 5'. The spatial distribution of gamma-ay photons is consistent with a point source. The average flux and power-law photon index measured with the LAT from 2008 August 4 to 2008 December 5 are F-gamma = (2.10 +/- 0.23) x 10(-7) ph (&gt;100 MeV) cm(-2) s(-1) and Gamma = 2.17 +/- 0.05, respectively. The measurements are statistically consistent with constant flux during the four-month LAT observing period. Previous EGRET observations gave an upper limit of F-gamma &lt; 3.72 x 10(-8) ph (&gt;100 MeV) cm(-2) s(-1) to the gamma-ray flux from NGC 1275. This indicates that the source is variable on timescales of years to decades, and therefore restricts the fraction of emission that can be produced in extended regions of the galaxy cluster. Contemporaneous and historical radio observations are also reported. The broadband spectrum of NGC 1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

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  • EARLY FERMI GAMMA-RAY SPACE TELESCOPE OBSERVATIONS OF THE QUASAR 3C 454.3

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, D. Donato, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, F. Rahoui, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, M. S. Shaw, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, J. A. Zensus, M. Ziegler

    ASTROPHYSICAL JOURNAL   699 ( 1 ) 817 - 823  2009.07  [Refereed]

     View Summary

    This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable.-ray emission with an average flux of similar to 3 x 10 (6) photons cm(-2) s(-1), for energies &gt; 100 MeV. The gamma-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor delta &gt; 8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (delta similar to 25). The observed gamma-ray spectrum is not consistent with a simple power law, but instead steepens strongly above similar to 2 GeV, and is well described by a broken power law with photon indices of similar to 2.3 and similar to 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2 GeV could be due to gamma-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (less than or similar to 100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

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  • BRIGHT ACTIVE GALACTIC NUCLEI SOURCE LIST FROM THE FIRST THREE MONTHS OF THE FERMI LARGE AREA TELESCOPE ALL-SKY SURVEY

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, A. W. Chen, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, W. Collmar, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, D. Horan, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, W. McConville, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. S. Shaw, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL   700 ( 1 ) 597 - 622  2009.07  [Refereed]

     View Summary

    The first three months of sky-survey operation with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope reveal 132 bright sources at |b| &gt; 10 degrees with test statistic greater than 100 ( corresponding to about 10 sigma). Two methods, based on the CGRaBS, CRATES, and BZCat catalogs, indicate high-confidence associations of 106 of these sources with known active galactic nuclei (AGNs). This sample is referred to as the LAT Bright AGN Sample (LBAS). It contains two radio galaxies, namely, Centaurus A and NGC 1275, and 104 blazars consisting of 58 flat spectrum radio quasars (FSRQs), 42 BL Lac objects, and 4 blazars with unknown classification. Four new blazars were discovered on the basis of the LAT detections. Remarkably, the LBAS includes 10 high-energy-peaked BL Lacs (HBLs), sources which were previously difficult to detect in the GeV range. Another 10 lower-confidence associations are found. Only 33 of the sources, plus two at |b| &lt; 10 degrees, were previously detected with Energetic Gamma-Ray Experiment Telescope( EGRET), probably due to variability. The analysis of the gamma-ray properties of the LBAS sources reveals that the average GeV spectra of BL Lac objects are significantly harder than the spectra of FSRQs. No significant correlation between radio and peak gamma-ray fluxes is observed. Blazar log N-log S distributions and luminosity functions are constructed to investigate the evolution of the different blazar classes, with positive evolution indicated for FSRQs but none for BL Lacs. The contribution of LAT blazars to the total extragalactic gamma-ray intensity is estimated.

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  • The large area telescope on the fermi gamma-ray space telescope mission

    W.B. Atwood, A.A. Abdo, M. Ackermann, W. Althouse, B. Anderson, M. Axelsson, L. Baldini, J. Ballet, D.L. Band, G. Barbiellini, J. Bartelt, D. Bastieri, B.M. Baughman, K. Bechtol, D. Bédérède, F. Bellardi, R. Bellazzini, B. Berenji, G.F. Bignami, D. Bisello, E. Bissaldi, R.D. Blandford, E.D. Bloom, J.R. Bogart, E. Bonamente, J. Bonnell, A.W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T.H. Burnett, G. Busetto, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carius, P. Carlson, J.M. Casandjian, E. Cavazzuti, M. Ceccanti, C. Cecchi, E. Charles, A. Chekhtman, C.C. Cheung, J. Chiang, R. Chipaux, A.N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Condamoor, J. Conrad, R. Corbet, L. Corucci, L. Costamante, S. Cutini, D.S. Davis, D. Decotigny, M. Deklotz, C.D. Dermer, A. De Angelis, S.W. Digel, E. Do Couto E Silva, P.S. Drell, R. Dubois, D. Dumora, Y. Edmonds, D. Fabiani, C. Farnier, C. Favuzzi, D.L. Flath, P. Fleury, W.B. Focke, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, F.-X. Gentit, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I.A. Grenier, M.-H. Grondin, J.E. Grove, L. Guillemot, S. Guiriec, G. Haller, A.K. Harding, P.A. Hart, E. Hays, S.E. Healey, M. Hirayama, L. Hjalmarsdotter, R. Horn, R.E. Hughes, G. Jóhannesson, G. Johansson, A.S. Johnson, R.P. Johnson, T.J. Johnson, W.N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, A. Kavelaars, N. Kawai, H. Kelly, M. Kerr, W. Klamra, J. Knödlseder, M.L. Kocian, N. Komin, F. Kuehn, M. Kuss, D. Landriu, L. Latronico, B. Lee, S.-H. Lee, M. Lemoine-Goumard, A.M. Lionetto, F. Longo, F. Loparco, B. Lott, M.N. Lovellette, P. Lubrano, G.M. Madejski, A. Makeev, B. Marangelli, M.M. Massai, M.N. Mazziotta, J.E. McEnery, N. Menon, C. Meurer, P.F. Michelson, M. Minuti, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A.A. Moiseev, C. Monte, M.E. Monzani, E. Moretti, A. Morselli, I.V. Moskalenko, S. Murgia, T. Nakamori, S. Nishino, P.L. Nolan, J.P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J.F. Ormes, A. Paccagnella, D. Paneque, J.H. Panetta, D. Parent, M. Pearce, M. Pepe, A. Perazzo, M. Pesce-Rollins, P. Picozza, L. Pieri, M. Pinchera, F. Piron, T.A. Porter, L. Poupard, S. Rainò, R. Rando, E. Rapposelli, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L.C. Reyes, S. Ritz, L.S. Rochester, A.Y. Rodriguez, R.W. Romani, M. Roth, J.J. Russell, F. Ryde, S. Sabatini, H.F.-W. Sadrozinski, D. Sanchez, A. Sander, L. Sapozhnikov, P.M.S. Parkinson, J.D. Scargle, T.L. Schalk, G. Scolieri, C. Sgrò, G.H. Share, M. Shaw, T. Shimokawabe, C. Shrader, A. Sierpowska-Bartosik, E.J. Siskind, D.A. Smith, P.D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, T.E. Stephens, M.S. Strickman, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, S. Tether, J.B. Thayer, J.G. Thayer, D.J. Thompson, L. Tibaldo, O. Tibolla, D.F. Torres, G. Tosti, A. Tramacere, M. Turri, T.L. Usher, N. Vilchez, V. Vitale, P. Wang, K. Watters, B.L. Wine

    Astrophysical Journal Letters   697 ( 2 ) 1071 - 1102  2009.06  [Refereed]

     View Summary

    The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy γ-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 × 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy γ-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (4) localize point sources to 0.3-2 arcmin, (5) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (6) measure the diffuse isotropic γ-ray background up to TeV energies, and (7) explore the discovery space for dark matter. © 2009. The American Astronomical Society. All rights reserved.

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  • Performance of a multi-anode photomultiplier employing an ultra bi-alkali photo-cathode and rugged dynodes

    T. Toizumi, S. Inagawa, T. Nakamori, J. Kataoka, Y. Tsubuku, Y. Yatsu, T. Shimokawabe, N. Kawai, T. Okada, I. Ohtsu

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 168 - 173  2009.06  [Refereed]

     View Summary

    We report on the performance testing of a multi-anode photomultiplier (MAPMT), the R8900-200-M16MOD-UBA, newly developed by Hamamatsu Photonics K.K. Although the R8900 series offers the great advantage of a highly sensitive surface (&gt;=-80% of physical area), the quantum efficiency (Q.E.) was relatively low (at up to 20%). This paper describes two substantial changes we have made to the R8900-200-M16MOD-UBA: (1) improving the Q.E. to the 40% level by employing an ultra bi-alkali (UBA) photocathode and (2) constructing a rugged dynode that can withstand vibration for future use in space. We measured each pixel signal at the single photoelectron level and the signals of scintillation photons by using a 16-pixel plastic scintillator array. Thanks to high Q.E., good energy resolution of 29.9% (FWHM) was obtained for 59.5 keV gamma-rays. We also demonstrated tolerance to vibration up to 17 G(rms) in possible launching vehicles. (C) 2009 Elsevier B.V. All rights reserved.

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    9
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  • Development of a low-noise analog front-end ASIC for APD-PET detectors

    M. Koizumi, J. Kataoka, S. Tanaka, H. Ishibashi, N. Kawai, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, K. Shimizu, H. Kubo

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 327 - 330  2009.06  [Refereed]

     View Summary

    We report on the development of a front-end ASIC for high spatial resolution PET detectors with time-of-flight capability based on LYSO scintillator arrays coupled with position-sensitive avalanche photodiode (APD) arrays. The ASIC is designed based on the open-IP LSI project led by JAXA and realized in TSMC 0.35-mu m CMOS technology. It consists of an 8-channel charge-sensitive amplifier, band-pass filters, differentiators, pulse-height and timing discriminators, and two-channel time-to-amplitude converters. As a result, energy resolution of 9.7% (FWHM) is obtained at 511 keV, with a time resolution below 970 ps (sigma). We will also report on the current status of developing a second-version ASIC designed to have 32-channel analog circuits with improved time resolution. (C) 2009 Elsevier B.V. All rights reserved.

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    10
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  • Development of large-area, reverse-type APD-arrays for high-resolution medical imaging

    J. Kataoka, M. Koizumi, S. Tanaka, H. Ishibashi, T. Nakamori, N. Kawai, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, S. Kishimoto, H. Kubo

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 323 - 326  2009.06  [Refereed]

     View Summary

    Avalanche photodiodes (APD) offer advantages in terms of weak scintillation detection, fast time response, and magnetic field insensitivity. We have developed new types of large-area, reverse-type APD-arrays specifically designed for high-resolution positron emission tomography (PET). Each device has a monolithic 16 x 16 (or 8 x 8) pixel structure with an active area of 1.0 (or 4.0, 0.25) mm(2) for each pixel. An excellent gain uniformity (&lt;= 10%) and low dark noise (&lt;= 0.3 nA) have been achieved, measured at room temperature. Energy resolution of 7.2% (FWHM) was obtained for the direct detection of 5.9 keV X-rays, while 10.2% (FWHM) was obtained for 662 keV gamma-rays when coupled with a LYSO scintillator matrix. An excellent time resolution of 102 ps (FWHM) was obtained for a monolithic, 3 mm phi APD pixel. These results suggest that APD-arrays could be a promising device for future applications in nuclear medicine. (C) 2009 Elsevier B.V. All rights reserved.

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    21
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  • SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM: SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE

    F. Aharonian, A. G. Akhperjanian, G. Anton, U. Barres de Almeida, A. R. Bazer-Bachi, Y. Becherini, B. Behera, K. Bernloehr, C. Boisson, A. Bochow, V. Borrel, E. Brion, J. Brucker, P. Brun, R. Buehler, T. Bulik, I. Buesching, T. Boutelier, P. M. Chadwick, A. Charbonnier, R. C. G. Chaves, A. Cheesebrough, L. M. Chounet, A. C. Clapson, G. Coignet, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Atai, W. Domainko, L. O. C. Drury, F. Dubois, G. Dubus, J. Dyks, M. Dyrda, K. Egberts, D. Emmanoulopoulos, P. Espigat, C. Farnier, F. Feinstein, F. Fiasson, A. Foerster, G. Fontaine, M. Fuessling, S. Gabici, Y. A. Gallant, L. Gerard, B. Giebels, J. F. Glicenstein, B. Glueck, P. Goret, D. Goehring, D. Hauser, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, M. Holleran, S. Hoppe, D. Horns, A. Jacholkowska, O. C. de Jager, C. Jahn, I. Jung, K. Katarzynski, U. Katz, S. Kaufmann, E. Kendziorra, M. Kerschhaggl, D. Khangulyan, B. Khelifi, D. Keogh, W. Kluzniak, N. Komin, K. Kosack, G. Lamanna, J.-P. Lenain, T. Lohse, V. Marandon, J. M. Martin, O. Martineau-Huynh, A. Marcowith, D. Maurin, T. J. L. McComb, M. C. Medina, R. Moderski, E. Moulin, M. Naumann-Godo, M. de Naurois, D. Nedbal, D. Nekrassov, J. Niemiec, S. J. Nolan, S. Ohm, J.-F. Olive, E. de Ona Wilhelmi, K. J. Orford, M. Ostrowski, M. Panter, M. Paz Arribas, G. Pedaletti, G. Pelletier, P.-O. Petrucci, S. Pita, G. Puehlhofer, M. Punch, A. Quirrenbach, B. C. Raubenheimer, M. Raue, S. M. Rayner, M. Renaud, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. RudaK, C. B. Rulten, J. Ruppel, V. Sahakian, A. Santangelo, R. Schlickeiser, F. M. Schoeck, R. Schroeder, U. Schwanke, S. Schwarzburg, S. Schwemmer, A. Shalchi, M. Sikora, J. L. Skilton, H. Sol, D. Spangler, L. Stawarz, R. Steenkamp, C. Stegmann, G. Superina, A. Szostek, P. H. Tam, J.-P. Tavernet, R. Terrier, O. Tibolla, C. van Eldik, G. Vasileiadis, C. Venter, L. Venter, J. P. Vialle, P. Vincent, M. Vivier, H. J. Voelk, F. Volpe, S. J. Wagner, M. Ward, A. A. Zdziarski, A. Zech, A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, A. W. Chen, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, R. Dubois, G. Dubus, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M.-H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, D. Horan, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knodlseder, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, F. Ryde, H. F.-W. Sadrozinski, D. Sanchez, A. Sander, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. Shaw, D. A. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. S. Strickman, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL LETTERS   696 ( 2 ) L150 - L155  2009.05  [Refereed]

     View Summary

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of gamma-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; &gt; 100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little (similar to 30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

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    141
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  • Measurement of the Cosmic Ray e(+)+e(-) Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, G. Bogaert, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, P. Carlson, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, G. Di Bernardo, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, D. Grasso, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, D. Kocevski, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. M. Massai, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, M. Pohl, T. A. Porter, S. Profumo, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A. P. Waite, E. Wallace, P. Wang, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    PHYSICAL REVIEW LETTERS   102 ( 18 ) 1101  2009.05  [Refereed]

     View Summary

    Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m(2) sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E-3.0 and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.

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  • FERMI/LARGE AREA TELESCOPE DISCOVERY OF GAMMA-RAY EMISSION FROM THE FLAT-SPECTRUM RADIO QUASAR PKS 1454-354

    A. A. Abdo, M. Ackermann, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, G. Bogaert, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, E. C. Ferrara, P. Fleury, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. Marelli, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, M. Ohno, T. Ohsugi, R. Ojha, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, M. S. Shaw, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler, P. G. Edwards, M. M. Chester, D. N. Burrows, M. Hauser, S. Wagner

    ASTROPHYSICAL JOURNAL   697 ( 1 ) 934 - 941  2009.05  [Refereed]

     View Summary

    We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy gamma-ray (GeV) emission from the flat-spectrum radio quasar PKS 1454-354 (z = 1.424). On 2008 September 4, the source rose to a peak flux of (3.5 +/- 0.7) x 10(-6) ph cm(-2) s(-1) (E &gt; 100 MeV) on a timescale of hours and then slowly dropped over the following 2 days. No significant spectral changes occurred during the flare. Fermi/LAT observations also showed that PKS 1454-354 is the most probable counterpart of the unidentified EGRET source 3EG J1500-3509. Multiwavelength measurements performed during the following days (7 September with Swift; 6-7 September with the ground-based optical telescope Automated Telescope for Optical Monitoring; 13 September with the Australia Telescope Compact Array) resulted in radio, optical, UV, and X-ray fluxes greater than archival data, confirming the activity of PKS 1454-354.

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  • FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE VELA PULSAR

    A. A. Abdo, M. Ackermann, W. B. Atwood, R. Bagagli, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, M. G. Baring, J. Bartelt, D. Bastieri, B. M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, B. Berenji, D. Bisello, R. D. Blandford, E. D. Bloom, J. R. Bogart, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, M. Ceccanti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, L. Corucci, S. Cutini, D. S. Davis, M. DeKlotz, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, D. L. Flath, P. Fleury, W. B. Focke, M. Frailis, P. C. C. Friere, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, R. Giannitrapani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, G. Haller, A. K. Harding, P. A. Hart, R. C. Hartman, E. Hays, G. Hobbs, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, G. Kanbach, V. M. Kaspi, H. Katagiri, J. Kataoka, A. Kavelaars, N. Kawai, H. Kelly, M. Kerr, B. Kiziltan, W. Klamra, J. Knodlseder, M. Kramer, F. Kuehn, M. Kuss, J. Lande, D. Landriu, L. Latronico, B. Lee, S. -H. Lee, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. G. Lyne, G. M. Madejski, A. Makeev, R. N. Manchester, B. Marangelli, M. Marelli, M. N. Mazziotta, J. E. McEnery, S. McGlynn, M. A. McLaughlin, N. Menon, C. Meurer, P. F. Michelson, T. Mineo, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. Mongelli, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, A. Paccagnella, D. Paneque, J. H. Panetta, D. Parent, M. Pearce, M. Pepe, M. Perchiazzi, M. Pesce-Rollins, L. Pieri, M. Pinchera, F. Piron, T. A. Porter, S. Raino, R. Rando, S. M. Ransom, E. Rapposelli, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, A. Sacchetti, H. F. -W. Sadrozinski, N. Saggini, D. Sanchez, A. Sander, P. M. Saz Parkinson, K. N. Segal, A. Sellerholm, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, J. -L. Starck, F. W. Stecker, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J. B. Thayer, J. G. Thayer, G. Theureau, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, D. F. Torres, A. Tramacere, M. Turri, T. L. Usher, L. Vigiani, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, K. Watters, P. Weltevrede, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL   696 ( 2 ) 1084 - 1093  2009.05  [Refereed]

     View Summary

    The Vela pulsar is the brightest persistent source in the GeV sky and thus is the traditional first target for new gamma-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure and early sky survey scanning. We have used the Vela signal to verify Fermi timing and angular resolution. The high-quality pulse profile, with some 32,400 pulsed photons at E &gt;= 0.03 GeV, shows new features, including pulse structure as fine as 0.3 ms and a distinct third peak, which shifts in phase with energy. We examine the high-energy behavior of the pulsed emission; initial spectra suggest a phase-averaged power-law index of Gamma = 1.51(-0.04)(+0.05) with an exponential cutoff at E-c = 2.9 +/- 0.1 GeV. Spectral fits with generalized cutoffs of the form e(-(E/Ec)b) require b &lt;= 1, which is inconsistent with magnetic pair attenuation, and thus favor outer-magnetosphere emission models. Finally, we report on upper limits to any unpulsed component, as might be associated with a surrounding pulsar wind nebula.

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  • DISCOVERY OF PULSED gamma-RAYS FROM THE YOUNG RADIO PULSAR PSR J1028-5819 WITH THE FERMI LARGE AREA TELESCOPE

    A. A. Abdo, M. Ackermann, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, N. Komin, M. Kramer, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, S. E. Thorsett, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A. P. Waite, K. Watters, K. S. Wood, T. Ylinen, M. Ziegler, G. Hobbs, M. Keith, R. N. Manchester, P. Weltevrede

    ASTROPHYSICAL JOURNAL LETTERS   695 ( 1 ) L72 - L77  2009.04  [Refereed]

     View Summary

    Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz) in the error circle of the Energetic Gamma-Ray Experiment Telescope (EGRET) source 3EG J1027-5817. The spin-down power of this young pulsar is great enough to make it very likely the counterpart for the EGRET source. We report here the discovery of gamma-ray pulsations from PSR J1028-5819 in early observations by the Large Area Telescope (LAT) on the Fermi Gamma-Ray Space Telescope. The gamma-ray light curve shows two sharp peaks having phase separation of 0.460 +/- 0.004, trailing the very narrow radio pulse by 0.200 +/- 0.003 in phase, very similar to that of other known gamma-ray pulsars. The measured gamma-ray flux gives an efficiency for the pulsar of similar to 10-20% (for outer magnetosphere beam models). No evidence of a surrounding pulsar wind nebula is seen in the current Fermi data but limits on associated emission are weak because the source lies in a crowded region with high background emission. However, the improved angular resolution afforded by the LAT enables the disentanglement of the previous COS-B and EGRET source detections into at least two distinct sources, one of which is now identified as PSR J1028-5819.

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  • A Monte Carlo method for calculating the energy response of plastic scintillators to polarized photons below 100 keV

    Mizuno T, Kanai Y, Kataoka J, Kiss M, Kurita K, Pearce M, Tajima H, Takahashi H, Tanaka T, Ueno M, Umeki Y, Yoshida H, Arimoto M, Axelsson M, Bettolo C. Marini, Bogaert G, Chen P, Craig W, Fukazawa Y, Gunji S, Kamae T, Katsuta J, Kawai N, Kishimoto S, Klamra W, Larsson S, Madejski G, Ng J. S. T, Ryde F, Rydstrom S, Takahashi T, Thurston T. S, Varner G

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   600 ( 3 ) 609 - 617  2009.03  [Refereed]

     View Summary

    The energy response of plastic scintillators (Eljen Technology EJ-204) to polarized soft gamma-ray photons below 100 keV has been studied, primarily for the balloon-borne polarimeter, PoGOLite. The response calculation includes quenching effects due to low-energy recoil electrons and the position dependence of the light collection efficiency in a 20 cm long scintillator rod. The broadening of the pulse-height spectrum, presumably caused by light transportation processes inside the scintillator, as well as the generation and multiplication of photoelectrons in the photomultiplier tube, were studied experimentally and have also been taken into account. A Monte Carlo simulation based on the Geant4 toolkit was used to model photon interactions in the scintillators. When using the polarized Compton/Rayleigh scattering processes previously corrected by the authors, scintillator spectra and angular distributions of scattered polarized photons could clearly be reproduced, in agreement with the results obtained at a synchrotron beam test conducted at the KEK Photon Factory. Our simulation successfully reproduces the modulation factor, defined as the ratio of the amplitude to the mean of the distribution of the azimuthal scattering angles, within ∼ 5 % (relative). Although primarily developed for the PoGOLite mission, the method presented here is also relevant for other missions aiming to measure polarization from astronomical objects using plastic scintillator scatterers. © 2008 Elsevier B.V.

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    10
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  • SUZAKU OBSERVATIONS OF THE EXTREME MeV BLAZAR SWIFT J0746.3+2548

    Shin Watanabe, Rie Sato, Tadayuki Takahashi, Jun Kataoka, Greg Madejski, Marek Sikora, Fabrizio Tavecchio, Rita Sambruna, Roger Romani, Philip G. Edwards, Tapio Pursimo

    ASTROPHYSICAL JOURNAL   694 ( 1 ) 294 - 301  2009.03  [Refereed]

     View Summary

    We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in 2005 November. This object, which, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics and high signal-to-noise ratio spectrum, the Suzaku observation clearly confirms that J0746 has an extremely hard spectrum in the energy range of 0.3-24 keV, which is well represented by a single power-law with a photon index of Gamma(ph) similar or equal to 1.17 and Galactic absorption. The multiwavelength spectral energy distribution of J0746 shows two continuum components, and is well modeled assuming that the high-energy spectral component results from Comptonization of the broad-line region photons. In this paper, we search for the bulk Compton spectral features predicted to be produced in the soft X-ray band by scattering external optical/UV photons by cold electrons in a relativistic jet. We discuss and provide constraints on the pair content resulting from the apparent absence of such features.

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    8
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  • Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    A. A. Abdo, M. Ackermann, M. Arimoto, K. Asano, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, M. G. Baring, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, B. Berenji, P. N. Bhat, E. Bissaldi, R. D. Blandford, E. D. Bloom, G. Bogaert, J. R. Bogart, E. Bonamente, J. Bonnell, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. S. Briggs, M. Brigida, P. Bruel, T. H. Burnett, D. Burrows, G. Busetto, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, M. Ceccanti, C. Cecchi, A. Celotti, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, V. Connaughton, J. Conrad, L. Costamante, S. Cutini, M. DeKlotz, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, B. L. Dingus, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, P. A. Evans, D. Fabiani, C. Farnier, C. Favuzzi, J. Finke, G. Fishman, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, A. Goldstein, J. Granot, J. Greiner, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, G. Haller, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, J. A. Hernando Morata, A. Hoover, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, A. Kavelaars, N. Kawai, H. Kelly, J. Kennea, M. Kerr, R. M. Kippen, J. Knoedlseder, D. Kocevski, M. L. Kocian, N. Komin, C. Kouveliotou, F. Kuehn, M. Kuss, J. Lande, D. Landriu, S. Larsson, L. Latronico, C. Lavalley, B. Lee, S. -H. Lee, M. Lemoine-Goumard, G. G. Lichti, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, B. Marangelli, M. N. Mazziotta, S. McBreen, J. E. McEnery, S. McGlynn, C. Meegan, P. Meszaros, C. Meurer, P. F. Michelson, M. Minuti, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, D. Nelson, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, W. S. Paciesas, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Perri, M. Pesce-Rollins, V. Petrosian, M. Pinchera, F. Piron, T. A. Porter, R. Preece, S. Raino, E. Ramirez-Ruiz, R. Rando, E. Rapposelli, M. Razzano, S. Razzaque, N. Rea, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, K. N. Segal, C. Sgro, T. Shimokawabe, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, J. -L. Starck, F. W. Stecker, H. Steinle, T. E. Stephens, M. S. Strickman, D. J. Suson, G. Tagliaferri, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, M. Turri, S. Tuvi, T. L. Usher, A. J. van der Horst, L. Vigiani, N. Vilchez, V. Vitale, A. von Kienlin, A. P. Waite, D. A. Williams, C. Wilson-Hodge, B. L. Winer, K. S. Wood, X. F. Wu, R. Yamazaki, T. Ylinen, M. Ziegler

    SCIENCE   323 ( 5922 ) 1688 - 1693  2009.03  [Refereed]

     View Summary

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gamma-ray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

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  • Modelling the broad-band spectra of X-ray emitting GPS galaxies

    L. Ostorero, R. Moderski, Stawarz, M. C. Begelman, A. Diaferio, I. Kowalska, J. Kataoka, S. J. Wagner

    Astronomische Nachrichten   330 ( 2-3 ) 275 - 278  2009.02

     View Summary

    The study of the broad-band emission of GHz-Peaked-Spectrum (GPS) radio galaxies is a powerful tool to investigate the physical processes taking place in the central, kpc-sized region of their active hosts, where the jets propagate and the lobes expand, interacting with the surrounding interstellar medium (ISM). We recently developed a new dynamical-radiative model to describe the evolution of the GPS phenomenon (Stawarz et al. 2008): as the relativistic jets propagate through the ISM, gradually engulfing narrow-line emitting gas clouds along their way, the electron population of the expanding lobes evolves, emitting synchrotron light, as well as inverse-Compton radiation via up-scattering of the photon fields from the host galaxy and its active nucleus. The model, which successfully reproduces the key features of the GPS radio sources as a class, provides a description of the evolution of their spectral energy distribution (SED) with the lobes' expansion, predicting significant and complex X-ray to γ-ray emission. We apply here the model to the broad-band SED's of a sample of known, X-ray emitting GPS galaxies, and show that (i) the free-free absorption mechanism enables us to reproduce the radio continuum at frequencies below the turnover; (ii) the lobes' non-thermal, inverse-Compton emission can account for the observed X-ray spectra, providing a viable alternative to the thermal, accretion-dominated scenario. We also show that, in our sample, the relationship between the X-ray and radio hydrogen column densities, NH and NHI, is suggestive of a positive correlation, which, if confirmed, would support the scenario of high-energy emitting lobes. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.

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    5
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  • On-board and Ground Data Processing System of MAXI

    ISHIKAWA Masaki, TAKAHASHI Daiki, MATSUOKA Masaru, UENO Shiro, TOMIDA Hiroshi, KATAYAMA Haruyoshi, KAWASAKI Kazuyoshi, KOHAMA Mitsuhiro, SUZUKI Motoko, ADACHI Yasuki, MIHARA Tatehiro, ISOBE Naoki, TSUNEMI Hiroshi, MIYATA Emi, YOSHIDA Atsumasa, YAMAOKA Kazutaka, KAWAI Nobuyuki, KATAOKA Jun, NAKAJIMA Motoki, NEGORO Hiroshi, MORII Mikio

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN   7 ( ists26 ) Tf_43 - Tf_48  2009

     View Summary

    MAXI (Monitor of All sky X-ray Image) is the first X-ray observation payload to be installed to EF (Exposed Facility) of Kibo (JEM: Japanese Experiment Module) on ISS (International Space Station). One of the important missions of MAXI is to quickly release novae or transient information of X-ray sources through its alert system to the worldwide astronomers. For this purpose, MAXI is equipped with a unique data transfer system both for the ground and on-board handling, which fully utilizes the communication system of ISS. The uniqueness of the data transfer system of MAXI comes from the fact that it is a payload of ISS, and is not seen in the ordinary payloads on free flyers (satellites). MAXI analyzes the observation data automatically in real time, and an alert for the novae or transient sources can be distributed widely through internet based on the analysis result. Various restrictions are imposed to keep tight security even on the ground system of ISS payloads. This paper describes the data transmission process in each stage, namely that in MAXI, the ISS communication links between the ISS and ground, and the process in the MAXI ground system.

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  • Versatile APD-based PET Modules for High Resolution, Fast Medical Imaging

    J. Kataoka, H. Matsuda, M. Yoshino, T. Miura, F. Nishikido, M. Koizumi, T. Tanaka, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, S. Kishimoto, H. Kubo

    2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5     3542 - +  2009  [Refereed]

     View Summary

    We report on the development of versatile APD-based PET modules with time-of-flight capability. The module consists of a LYSO matrix optically coupled with a position-sensitive avalanche photodiode (APD) array, and front-end circuits (FEC) directly connected to the rear-end of the APD package. Each APD device has a monolithic 16x16 (or 8x8) pixel structure with an active area of 1.0 (or 4.0) mm(2) for each pixel. Time resolutions of 155 ps and 214 ps (FWHM) were obtained for 1.0 mm(2) and 4.0 mm(2) APD pixels, respectively, measured by the direct detection of 10 keV X-rays. The FEC carries two identical analog ASICs specifically designed for the APDs in TSMC 0.35 mu m CMOS technology. Each ASIC consists of 32-channel charge-sensitive amplifiers, band-pass filters, differentiators, pulse-height and timing discriminators, and two-channel time-to-amplitude converters. The noise characteristic of the ASIC, mounted in a low temperature co-fired ceramics (LTCC) package, is 560 +30 e(-)/pF with an electric timing resolution of 484 ps (rms). The overall dimension of the module (including APD-array, LYSO matrix and FEC) is 30x30x80 mm(3). The variation of signal amplitude was less than 20% among all pixels. The average energy resolutions of 11.7 +/- 0.7 % and 13.7 +/- 1.1 % were obtained for 662 key gamma-rays, measured with 8x8 and 16x16 arrays, respectively. An attainable spatial resolution is &lt; 0.8mm (FWHM) for 16x16 array in a reconstructed image. These results suggest the APD-based PET module can be a promising device for future applications, especially for high resolution MRI- and TOF-PET.

  • The Soft Gamma-Ray Detector for the ASTRO-H Mission

    T. Tanaka, R. Blandford, K. Doutsu, T. Endo, T. Enoto, Y. Fukazawa, K. Fukami, T. Fukuyama, Y. Hanabata, J. Harayama, K. Hayashi, K. Hiragi, S. Ishikawa, J. Kataoka, J. Katsuta, T. Kitaguchi, M. Kokubun, M. Koseki, T. Kozu, G. Madejski, K. Makishima, M. Matsuoka, T. Miura, T. Mizuno, S. Nakahira, K. Nakajima, K. Nakazawa, S. Nishino, H. Nishioka, H. Noda, H. Odaka, S. Saito, S. Sasaki, R. Sato, S. Sugimoto, H. Tajima, T. Takahashi, M. Tashiro, Y. Terada, S. Torii, Y. Uchiyama, Y. Umeki, S. Watanabe, Y. Yaji, S. Yamada, K. Yamaoka, M. Yoshino, T. Yuasa

    2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5     2140 - 2144  2009  [Refereed]

     View Summary

    The Soft Gamma-ray Detector (SGD) on board ASTRO-H (Japanese next high-energy astrophysics mission) is a Compton telescope with narrow field-of-view, which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) detectors. It can detect photons in a wide energy band (50-600 keV) at a background level 10 times better than that of the Suzaku Hard X-ray Detector, and is complimentary to the Hard X-ray Imager on board ASTRO-H with an energy coverage of 5-80 keV. Excellent energy resolution is the key feature of the SGD, allowing it to achieve good background rejection capability taking advantage of good angular resolution. An additional capability of the SGD, its ability to measure gamma-ray polarization, opens up a new window to study properties of gamma-ray emission processes. Here we describe the instrument design of the SGD, its expected performance, and its development status.

  • Beam, Test Results of the Polarized Gamma-Ray Observer, PoGOLite

    H. Takahashi, M. Matsuoka, Y. Umeki, H. Yoshida, T. Tanaka, T. Mizuno, Y. Fukazawa, T. Kamae, G. Madejski, H. Tajima, M. Kiss, W. Klamra, S. Larsson, C. Marini Bettolo, M. Pearce, F. Ryde, S. Rydstrom, K. Kurita, Y. Kanai, M. Arimoto, A. Ueno, J. Kataoka, N. Kawai, M. Axelsson, L. Hjalmarsdotter, G. Bogaert, S. Gunji, T. Takahashi, G. Varner, T. Yuasa

    2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9     13 - +  2009  [Refereed]

     View Summary

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy range 25-80 keV. During a beam test at KEK-PF in February 2008, 20 detector units were assembled, and a 50 keV X-ray beam with a polarization degree of similar to 90% was irradiated at the center unit. Signals from all 20 units were fed into flight-version electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 PDCs, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be similar to 34%. These results confirmed the capabilities of both detector and data-acquisition system for a pathfinder flight planned in 2010.

  • TSUBAME: toward the Frontier of X-ray/Gamma-ray Polarimetry in Astronomy

    TOIZUMI Takahiro, KATAOKA Jun, TSUBUKU Yoshihiro, KOBAYASHI Mitsuyoshi, YATSU Yoichi, ARIMOTO Makoto, SHIMOKAWABE Takashi, KAWAI Nobuyuki, OMAGARI Kuniyuki, FUJIWARA Ken, ASHIDA Hiroki, NISHIDA Junichi, FUJIHASHI Kota, INAGAWA Shinich, MIURA Yoshiyuki, MATSUNAGA Saburo

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN   7 ( 26 ) Tm_31 - Tm_35  2009

     View Summary

    "TSUBAME" is a university-built small satellite mission to measure polarization of hard X-ray photons (30-200 keV) from gamma-ray bursts (GRBs) using azimuthal anisotropy of Compton-scattered photons. Polarimetry in the hard X-ray and soft γ-ray bands should provide crucial information for understanding the high-energy emission mechanisms and the distribution of magnetic fields and radiation fields in the astrophysical sources. TSUBAME has two instruments: the Wide-field Burst Monitor (WBM) and the Hard X-ray Compton Polarimeter (HXCP). The WBM determines on board the direction of the burst occurrence with an accuracy of 10 degrees, then using a high speed attitude control device, the HXCP is pointed to the GRB within 15 seconds after the burst occurrence to promptly detect polarized X-ray photons from the GRB. We present an overview of the TSUBAME mission, its estimated scientific capability for detecting GRBs and measuring their X-ray polarization, development of multi-anode photomultiplier tubes that use ultra bi-alkali photocathodes, and the future plans of this mission.

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  • Discovery of pulsations from the pulsar J0205+6449 in SNR 3C 58 with the fermi gamma-ray space telescope

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, M. Dormody, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Espinoza, C. Farnier, C. Favuzzi, W. B. Focke, M. Frailis, P. C.C. Freire, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, G. Hobbs, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, V. M. Kaspi, H. Katagiri, J. Kataoka, N. Kawai, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M. N. Lovellette

    Astrophysical Journal   699 ( 2 PART 2 )  2009

     View Summary

    We report the discovery of γ-ray pulsations (≥0.1 GeV) from the young radio and X-ray pulsar PSR J0205 + 6449 located in the Galactic supernova remnant 3C 58. Data in the γ-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold γ-rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 ± 0.01 ± 0.01 cycles which are aligned with the X-ray peaks. The first γ-ray peak trails the radio pulse by 0.08 ± 0.01 ± 0.01, while its amplitude decreases with increasing energy as for the other γ-ray pulsars. Spectral analysis of the pulsed γ-ray emission suggests a simple power law of index -2.1 ± 0.1 ± 0.2 with an exponential cutoff at 3.0+1.1-0.7 ± 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral γ-ray photon flux above 0.1 GeV is (13.7 ± 1.4 ± 3.0) × 10-8cm-2s -1, which implies for a distance of 3.2kpc and assuming a broad fan-like beam a luminosity of 8.3 × 1034ergs-1 and an efficiency η of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 × 10-8cm-2s-1 for off-pulse emission from the object. © 2009. The American Astronomical Society. All rights reserved.

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  • Simultaneous multiwavelength observation of mkn 501 in a low state in 2006

    H. Anderhub, L. A. Antonelli, P. Antoranz, M. Backes, C. Baixeras, S. Balestra, J. A. Barrio, D. Bastieri, J. Becerra Gonzlez, J. K. Becker, W. Bednarek, K. Berger, E. Bernardini, A. Biland, R. K. Bock, G. Bonnoli, P. Bordas, D. Borla Tridon, V. Bosch-Ramon, D. Bose, I. Braun, T. Bretz, I. Britvitch, M. Camara, E. Carmona, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, S. Covino, V. Curtef, F. Dazzi, A. De Angelis, E. De Cea Del Pozo, R. De Los Reyes, B. De Lotto, M. De Maria, F. De Sabata, C. Delgado Mendez, A. Dominguez, D. Dorner, M. Doro, D. Elsaesser, M. Errando, D. Ferenc, E. Fernndez, R. Firpo, M. V. Fonseca, L. Font, N. Galante, R. J.García López, M. Garczarczyk, M. Gaug, F. Goebel, D. Hadasch, M. Hayashida, A. Herrero, D. Hildebrand, D. Höhne-Mönch, J. Hose, C. C. Hsu, T. Jogler, D. Kranich, A. La Barbera, A. Laille, E. Leonardo, E. Lindfors, S. Lombardi, F. Longo, M. López, E. Lorenz, P. Majumdar, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, D. Mazin, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, H. Miyamoto, J. Moldón, M. Moles, A. Moralejo, D. Nieto, K. Nilsson, J. Ninkovic, N. Otte, I. Oya, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. G. Pegna, M. A. Perez-Torres, M. Persic

    Astrophysical Journal   705 ( 2 ) 1624 - 1631  2009

     View Summary

    We present results of the multiwavelength campaign on the TeV blazar Mkn 501 performed in 2006 July, including MAGIC for the very-high-energy (VHE) γ-ray band and Suzaku for the X-ray band. A VHE γ-ray signal was clearly detected with an average flux above 200 GeV of 20% of the Crab Nebula flux, which indicates a low state of source activity in this energy range. No significant variability has been found during the campaign. The VHE γ-ray spectrum can be described by a simple power law from 80 GeV to 2 TeV with a photon index of 2.8 0.1, which corresponds to one of the steepest photon indices observed in this energy range so far for this object. The X-ray spectrum covers a wide range from 0.6 to 40 keV, and is well described by a broken power law, with photon indices of 2.257 0.004 and 2.420 0.012 below and above the break energy of 3.24+0.13-0.12 keV. No apparent high-energy cut-off is seen above the break energy. Although an increase of the flux of about 50% is observed in the X-ray band within the observation, the data indicate a consistently low state of activity for this source. Time-resolved spectra show an evidence for spectral hardening with a flux level. A homogeneous one-zone synchrotron self-Compton (SSC) model can adequately describe the spectral energy distribution (SED) from the X-ray to the VHE γ-ray bands with a magnetic field intensity B = 0.313 G and a Doppler beaming factor δ = 20, which are similar to the values in the past multiwavelength campaigns in high states. Based on our SSC parameters derived for the low state, we are able to reproduce the SED of the high state by just changing the Lorentz factor of the electrons corresponding to the break energy in the primary electron spectrum. This suggests that the variation of the injected electron population in the jet is responsible for the observed low-high state variation of the SED. © 2009 The American Astronomical Society. All rights reserved.

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  • The MAXI mission on the ISS: Science and instruments for monitoring All-sky X-ray Images

    Masaru Matsuoka, Kazuyoshi Kawasaki, Shiro Ueno, Hiroshi Tomida, Mitsuhiro Kohama, Motoko Suzuki, Yasuki Adachi, Masaki Ishikawa, Tatehiro Mihara, Mutsumi Sugizaki, Naoki Isobe, Yujin Nakagawa, Hiroshi Tsunemi, Emi Miyata, Nobuyuki Kawai, Jun Kataoka, Mikio Morii, Atsumasa Yoshida, Hitoshi Negoro, Motoki Nakajima, Yoshihiro Ueda, Hirotaka Chujo, Kazutaka Yamaoka, Osamu Yamazaki, Satoshi Nakahira, Tetsuya You, Ryoji Ishiwata, Sho Miyoshi, Satoshi Eguchi, Kazuo Hiroi, Haruyoshi Katayama, Ken Ebisawa

    Publications of the Astronomical Society of Japan   61 ( 5 ) 999 - 1010  2009

     View Summary

    The Monitor of All-sky X-ray Image (MAXI) mission is the first astronomical payload to be installed on the Japanese Experiment Module - Exposed Facility (JEM-EF or Kibo-EF) on the International Space Station. It has two types of X-ray slit cameras with wide FOVs and two kinds of X-ray detectors consisting of gas proportional counters covering the energy range of 2 to 30 keV and X-ray CCDs covering the energy range of 0.5 to 12 keV. MAXI will be more powerful than any previous X-ray All Sky Monitor payloads, being able to monitor hundreds of Active Galactic Nuclei. A realistic simulation under optimal observation conditions suggests that MAXI will provide all-sky images of X-ray sources of ∼20 mCrab (∼7 × 10-10ergcm-2s-1 in the energy band of 2-30 keV) from observations during one ISS orbit (90 min), ∼4.5 mCrab for one day, and ∼2 mCrab for one week. The final detectability of MAXI could be ∼0.2 mCrab for two years, which is comparable to the source confusion limit of the MAXI field of view (FOV). The MAXI objectives are: (1) to alert the community to X-ray novae and transient X-ray sources, (2) to monitor long-term variabilities of X-ray sources, (3) to stimulate multi-wavelength observations of variable objects, (4) to create unbiased X-ray source cataloges, and (5) to observe diffuse cosmic X-ray emissions, especially with better energy resolution for soft X-rays down to 0.5 keV. © 2009. Astronomical Society of Japan.

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  • Multiwavelength observations of 3C 454.3. II. the agile 2007 december campaign

    I. Donnarumma, G. Pucella, V. Vittorini, F. D'Ammando, S. Vercellone, C. M. Raiteri, M. Villata, M. Perri, W. P. Chen, R. L. Smart, J. Kataoka, N. Kawai, Y. Mori, G. Tosti, D. Impiombato, T. Takahashi, R. Sato, M. Tavani, A. Bulgarelli, A. W. Chen, A. Giuliani, F. Longo, L. Pacciani, A. Argan, G. Barbiellini, F. Boffelli, P. Caraveo, P. W. Cattaneo, V. Cocco, T. Contessi, E. Costa, E. Del Monte, G. De Paris, G. Di Cocco, Y. Evangelista, M. Feroci, A. Ferrari, M. Fiorini, T. Froysland, M. Frutti, F. Fuschino, M. Galli, F. Gianotti, C. Labanti, I. Lapshov, F. Lazzarotto, P. Lipari, M. Marisaldi, M. Mastropietro, S. Mereghetti, E. Morelli, E. Moretti, A. Morselli, A. Pellizzoni, F. Perotti, G. Piano, P. Picozza, M. Pilia, G. Porrovecchio, M. Prest, M. Rapisarda, A. Rappoldi, A. Rubini, S. Sabatini, E. Scalise, P. Soffitta, E. Striani, M. Trifoglio, A. Trois, E. Vallazza, A. Zambra, D. Zanello, C. Pittori, P. Santolamazza, F. Verrecchia, P. Giommi, L. A. Antonelli, S. Colafrancesco, L. Salotti

    Astrophysical Journal   707 ( 2 ) 1115 - 1123  2009

     View Summary

    We report on the second Astrorivelatore Gamma a Immagini Leggero (AGILE) multiwavelength campaign of the blazar 3C 454.3 during the first half of 2007 December. This campaign involved AGILE, Spitzer, Swift, Suzaku, the Whole Earth Blazar Telescope (WEBT) consortium, the Rapid Eye Mount (REM), and the Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME) telescopes, offering a broadband coverage that allowed for a simultaneous sampling of the synchrotron and inverse Compton (IC) emissions. The two-week AGILE monitoring was accompanied by radio to optical monitoring by WEBT and REM, and by sparse observations in mid-infrared and soft/hard X-ray energy bands performed by means of Target of Opportunity observations by Spitzer, Swift, and Suzaku, respectively. The source was detected with an average flux of ∼250 × 10-8photonscm-2s-1 above 100 MeV, typical of its flaring states. The simultaneous optical and γ-ray monitoring allowed us to study the time lag associated with the variability in the two energy bands, resulting in a possible ≲one-day delay of the γ-ray emission with respect to the optical one. From the simultaneous optical and γ-ray fast flare detected on December 12, we can constrain the delay between the γ-ray and optical emissions within 12 hr. Moreover, we obtain three spectral energy distributions (SEDs) with simultaneous data for 2007 December 5, 13, and 15, characterized by the widest multifrequency coverage. We found that a model with an external Compton on seed photons by a standard disk and reprocessed by the broad-line regions does not describe in a satisfactory way the SEDs of 2007 December 5, 13, and 15. An additional contribution, possibly from the hot corona with T = 106 K surrounding the jet, is required to account simultaneously for the softness of the synchrotron and the hardness of the IC emissions during those epochs. © 2009. The American Astronomical Society. All rights reserved.

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  • VERITAS upper limit on the very high energy emission from the radio galaxy NGC 1275

    V. A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Bautista, M. Beilicke, W. Benbow, D. Boltuch, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. Byrum, A. Cannon, O. Celik, A. Cesarini, L. Ciupik, P. Cogan, W. Cui, R. Dickherber, C. Duke, S. J. Fegan, J. P. Finley, P. Fortin, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, G. H. Gillanders, S. Godambe, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, D. Horan, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. Lebohec, G. Maier, A. McCann, M. McCutcheon, J. Millis, P. Moriarty, R. Mukherjee, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, M. Pohl, J. Quinn, K. Ragan, P. T. Reynolds, E. Roache, H. J. Rose, M. Schroedter, G. H. Sembroski, A. W. Smith, D. Steele, S. P. Swordy, M. Theiling, J. A. Toner, A. Varlotta, V. V. Vassiliev, S. Vincent, R. G. Wagner, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, S. Wissel, M. Wood, B. Zitzer, J. Kataoka, E. Cavazzuti, C. C. Cheung, B. Lott, D. J. Thompson, G. Tosti

    Astrophysical Journal   706 ( 2 PART 2 )  2009

     View Summary

    The recent detection by the Fermi γ-ray space telescope of high-energy γ-rays from the radio galaxy NGC1275 makes the observation of the very high energy (VHE: E>100GeV) part of its broadband spectrum particularly interesting, especially for the understanding of active galactic nuclei with misaligned multi-structured jets. The radio galaxy NGC 1275 was recently observed by VERITAS at energies above 100GeV for about 8hr. No VHE γ-ray emission was detected by VERITAS from NGC 1275. A 99% confidence level upper limit of 2.1% of the Crab Nebula flux level is obtained at the decorrelation energy of approximately 340GeV, corresponding to 19% of the power-law extrapolation of the Fermi Large Area Telescope result. © 2009. The American Astronomical Society. All rights reserved.

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  • Radio-loud narrow-line Seyfert 1 as a new class of gamma-ray active galactic nuclei

    A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, C. D. Dermer, F. De Palma, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, L. Foschini, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, L. Guillemot, S. Guiriec, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, G. Jóhannesson, A. S. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes

    Astrophysical Journal   707 ( 2 PART 2 )  2009

     View Summary

    We report the discovery with Fermi/LAT of γ-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z = 0.409), 1H 0323+342 (z = 0.061), and PKS 2004 - 447 (z = 0.24). In addition to PMN J0948+0022 (z = 0.585), the first source of this type to be detected in γ rays, they may form an emerging new class of γ-ray active galactic nuclei (AGNs). These findings can have strong implications on our knowledge about relativistic jets and the unified model of the AGN. © 2009. The American Astronomical Society.

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  • Fermi/lat observations of LS 5039

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Corbel, R. Corbet, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Docouto E Silva, P. S. Drell, R. Dubois, G. Dubus, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, A. B. Hill, D. Horan, R. E. Hughes, M. S. Jackson, G. Jóhannesson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. L. Kocian, F. Kuehn, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo

    Astrophysical Journal   706 ( 1 PART 2 )  2009

     View Summary

    The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 ± 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9 ± 0.5(stat) 1.8(syst) ×10-7 photon cm-2 s-1, with a cutoff at 2.1 ± 0.3(stat) 1.1(syst) GeV and photon index Γ = 1.9 ± 0.1(stat) 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi. © 2009. The American Astronomical Society. All rights reserved.

    DOI

    Scopus

    143
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    (Scopus)
  • Can the extragalactic gamma-ray background be explained by AGN?

    Tanja M. Kneiske, Karl Mannheim, Lukasz Stawarz, Jun Kataoka

    AIP Conference Proceedings   1085   510 - 513  2009

     View Summary

    Very high energy gamma-rays from blazars traversing cosmological distances through the meta-galactic radiation field can convert into electron-positron pairs in photon-photon collisions. The converted gamma-rays initiate electromagnetic cascades driven by inverse-Compton scattering with microwave background photons. Using a model for the time-dependent meta-galactic radiation field consistent with currently available far-infrared to optical data, the cascade contributions by faint, unresolved sources like blazars and FRI galaxies have been calculated. We come to the conclusion that depending on what is known so far about AGN, they are not able to produce the total extragalactic flux detected by EGRET. A test for the model will be the upcoming observations with FERMI. It would also be helpful to detect a signal above 100 GeV where the gamma-ray flux declines to 10-7GeV sr-1 cm-2 s-1. © 2009 American Institute of Physics.

    DOI

    Scopus

  • Chandra reveals twin X-ray jets in the powerful FR II radio galaxy 3C 353

    Jun Kataoka

    AIP Conference Proceedings   1085   435 - 438  2009

     View Summary

    We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-ray Observatory. 3C 353's two 4"-wide and 2'-long jets allow us to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the sub-arcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the jet and the counterjet, the terminal jet regions (hotspots), and one radio lobe. We show that the detection of the X-ray emission associated with the radio knots and counterknots, which is most likely non-thermal in origin, puts several crucial constraints on the X-ray emission mechanisms in powerful large-scale jets of quasars and FR II sources. In particular, we show that this detection is inconsistent with the inverse-Compton model proposed in the literature, and instead implies a synchrotron origin of the X-ray jet photons. We also find that the width of the X-ray counterjet is possibly narrower than that measured in radio bands, that the radio-to-X-ray flux ratio decreases systematically downstream along the jets, and that there are substantial (kpc-scale) offsets between the positions of the X-ray and radio intensity maxima within each knot, whose magnitudes increase away from the nucleus. We discuss all these findings in the wider context of the physics of extragalactic jets, proposing some particular though not definitive solutions or interpretations for each problem. In general, we find that the synchrotron X-ray emission of extragalactic large-scale jets is not only shaped by the global hydrodynamical configuration of the outflows, but is also likely to be very sensitive to the microscopic parameters of the jet plasma. A complete, self-consistent model for the X-ray emission of extragalactic jets still remains elusive. © 2009 American Institute of Physics.

    DOI

    Scopus

  • Status and expected perfomance of the MAXI mission for the JEM/ISS

    J. Kataoka, N. Kawai

    AIP Conference Proceedings   1085   830 - 833  2009

     View Summary

    MAXI (Monitor of All-sky X-ray Image) is the first payload to be attached on JEM-EF (Kibo exposed facility) of ISS. It provides an all sky X-ray image every ISS orbit. Only with a few weeks scan, MAXI is expected to make a milli-Crab X-ray all sky map excluding bright region around the sun. Thus, MAXI does not only inform X-ray novae and transients rapidly to world astronomers if once they occur, but also observes long-term variability of Galact ic and extra-Galactic X-ray sources. MAXI also provides an X-ray source catalogue at that time with diffuse cosmic X-ray background. MAXI consists of two kinds of detectors, position sensitive gas-proportional counters for 2-30 keV X-rays and CCD cameras for 0.5-10 keV X-rays. All instruments of MAXI are now in final phase of pre-launching tests of their flight modules. We are also carrying out performance tests for X-ray detectors and collimators. Data processing and analysis software including alert system on ground are being developed by mission team. In this paper we report an overview of final instruments of MAXI and capability of MAXI. © 2009 American Institute of Physics.

    DOI

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  • Development of wide-band X-ray/gamma-ray imagers using reach through APD arrays

    T. Nakamori, J. Kataoka, T. Toizumi, M. Koizumi, S. Tanaka, Y. Kanai, Y. Yatsu, N. Kawai, Y. Ishikawa, T. Kawai, N. Kawabata, Y. Matsunaga

    GAMMA-RAY BUSTS   1133   73 - +  2009  [Refereed]

     View Summary

    It is quite important to obtain wide band spectra of gamma-ray bursts (GRBs) at the same time in order to probe the emission processes or the structure of GRBs. An avalanche photo diode (APD) is a compact photon sensor with an internal gain of 100. We have developed an X-ray/gamma-ray detector using a back-illuminated reach-through APD (5x5mm(2)) optically coupled with a conventional CsI(Tl) scintillator, which covers typically from 1 keV to 1 MeV. Further, we developed a 1-dimensional array of the 8/16 APDs (net 16x20 mm(2)) for the purpose of an imaging photon detector to be used in future GRB missions. Here we present the current status and performance of our hybrid detector.

    DOI

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  • Versatile APD-based PET modules for high resolution, fast medical imaging

    J. Kataoka, H. Matsuda, M. Yoshino, T. Miura, F. Nishikido, M. Koizumi, T. Tanaka, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, S. Kishimoto, H. Kubo

    IEEE Nuclear Science Symposium Conference Record     3542 - 3545  2009  [Refereed]

     View Summary

    We report on the development of versatile APD-based PET modules with time-of-flight capability. The module consists of a LYSO matrix optically coupled with a position-sensitive avalanche photodiode (APD) array, and front-end circuits (FEC) directly connected to the rear-end of the APD package. Each APD device has a monolithic 16x16 (or 8x8) pixel structure with an active area of 1.0 (or 4.0) mm2 for each pixel. Time resolutions of 155 ps and 214 ps (FWHM) were obtained for 1.0 mm2 and 4.0 mm2 APD pixels, respectively, measured by the direct detection of 10 keV X-rays. The FEC carries two identical analog ASICs specifically designed for the APDs in TSMC 0.35 μm CMOS technology. Each ASIC consists of 32-channel charge-sensitive amplifiers, band-pass filters, differentiators, pulse-height and timing discriminators, and two-channel time-to-amplitude converters. The noise characteristic of the ASIC, mounted in a low temperature co-fired ceramics (LTCC) package, is 560 +30 e-/pF with an electric timing resolution of 484 ps (rms). The overall dimension of the module (including APD-array, LYSO matrix and FEC) is 30x30x80 mm3. The variation of signal amplitude was less than 20% among all pixels. The average energy resolutions of 11.7 ± 0.7 % and 13.7 ± 1.1 % were obtained for 662 keV gamma-rays, measured with 8x8 and 16x16 arrays, respectively. An attainable spatial resolution is < 0.8mm (FWHM) for 16x16 array in a reconstructed image. These results suggest the APD-based PET module can be a promising device for future applications, especially for high resolution MRI- and TOF-PET. ©2009 IEEE.

    DOI J-GLOBAL

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    (Scopus)
  • Development of the X-ray polarimetry small sattellite "TSUBAME"

    Toizumi T, Nakamori T, Kataoka J, Tsubuku Y, Yatsu Y, Shimokawabe T, Arimoto M, Kawai N, Omagari K, Ashida H, Matsunaga S

    GAMMA-RAY BUSTS   1133   85 - 87  2009

     View Summary

    TSUBAME is a university-built small satellite mission to measure polarization of hard X-ray photons (30-100 keV) from gamma-ray bursts using azimuthal angle anisotropy of Compton-scattered photons. Polarimetry in the hard X-ray and soft gamma-ray band should play a crucial role in the understanding of high energy emission mechanisms and the distribution of magnetic fields and radiation fields. TSUBAME has two instruments: the Wide-field Bust Monitor (WBM) and the Hard X-ray Compton Polarimeter (HXCP). The WBM detects a burst and determines on board the direction of the burst occurrence with an accuracy of 10 degrees. The spacecraft is then slewed to the GRB in 15 seconds from the trigger using CMG, a high speed attitude control device. HXCP will measure the polarized X-ray photons from the GRB while the spacecraft is slowly spinning around the bore sight. In this paper, we present an overview of the TSUBAME mission, its expected performance of X-ray polarization measurement based on Monte Carlo simulation, and the detectors. © 2009 American Institute of Physics.

    DOI

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  • The soft gamma-ray detector for the ASTRO-H mission

    T. Tanaka, R. Blandford, K. Doutsu, T. Endo, T. Enoto, Y. Fukazawa, K. Fukami, T. Fukuyama, Y. Hanabata, J. Harayama, K. Hayashi, K. Hiragi, S. Ishikawa, J. Kataoka, J. Katsuta, T. Kitaguchi, M. Kokubun, M. Koseki, T. Kozu, G. Madejski, K. Makishima, M. Matsuoka, T. Miura, T. Mizuno, S. Nakahira, K. Nakajima, K. Nakazawa, S. Nishino, H. Nishioka, H. Noda, H. Odaka, S. Saito, S. Sasaki, R. Sato, S. Sugimoto, H. Tajima, T. Takahashi, M. Tashiro, Y. Terada, S. Torii, Y. Uchiyama, Y. Umeki, S. Watanabe, Y. Yaji, S. Yamada, K. Yamaoka, M. Yoshino, T. Yuasa

    IEEE Nuclear Science Symposium Conference Record     2140 - 2144  2009  [Refereed]

     View Summary

    The Soft Gamma-ray Detector (SGD) on board ASTRO-H (Japanese next high-energy astrophysics mission) is a Compton telescope with narrow field-of-view, which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) detectors. It can detect photons in a wide energy band (50-600 keV) at a background level 10 times better than that of the Suzaku Hard X-ray Detector, and is complimentary to the Hard X-ray Imager on board ASTRO-H with an energy coverage of 5-80 keV. Excellent energy resolution is the key feature of the SGD, allowing it to achieve good background rejection capability taking advantage of good angular resolution. An additional capability of the SGD, its ability to measure gamma-ray polarization, opens up a new window to study properties of gamma-ray emission processes. Here we describe the instrument design of the SGD, its expected performance, and its development status. ©2009 IEEE.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Suzaku observation of TeV blazar the 1ES 1218+304: clues on particle acceleration in an extreme TeV blazar

    R. Sato, J. Kataoka, T. Takahashi, G. M. Medejski, S. Ruegamer, S. J. Wagner

    HIGH ENERGY GAMMA-RAY ASTRONOMY   1085   447 - +  2009  [Refereed]

     View Summary

    We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of similar to 2 on a timescale of 5 x 10(4) s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft X-rays, with the maximum lag of 2.3X10(4) s observed between the 0.3-1 keV and 5-10 keV bands, Furthermore we discovered that the temporal profile of the flare clearly changes with energy, being more symmetric at higher energies. From the spectral fitting of multi-wavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B similar to 0.047 G, an emission region size R = 3.0 x 10(16) cm for an appropriate beaming with a Doppler factor of delta = 20. This value of B is in good agreement with an independent estimate through the model fit to the observed time lag ascribing the energy-dependent variability to differential acceleration timescale of relativistic electrons provided that the gyro-factor xi is 10(5).

    DOI

    Scopus

  • Suzaku Observations of Tycho's Supernova Remnant

    Toru Tamagawa, Asami Hayato, Satoshi Nakamura, Yukikatsu Terada, Aya Bamba, Junko S. Hiraga, John P. Hughes, Una Hwang, Jun Kataoka, Kenzo Kinugasa, Hideyo Kunieda, Takaaki Tanaka, Hiroshi Tsunemi, Masaru Ueno, Stephen S. Holt, Motohide Kokubun, Emi Miyata, Andrew Szymkowiak, Tadayuki Takahashi, Keisuke Tamura, Daisuke Ueno, Kazuo Makishima

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   61 ( SUPPL. 1 ) S167 - S174  2009.01  [Refereed]

     View Summary

    Tycho's supernova remnant was observed by the XIS and HXD instruments onboard the Suzaku satellite on 2006 June 26-29 for 92 ks. The spectrum up to 30 keV was well fitted with a two-component model, consisting of a power-law with a photon index of 2.7 and a thermal bremsstrahlung model with a temperature of 4.7 keV. The former component can alternatively be modeled as synchrotron emission from a population of relativistic electrons with an estimated roll-off energy of around 1 keV. In the XIS spectra, in addition to the prominent Fe K alpha line (6.445 keV), we observed for the first time significant K alpha line emission from trace species Cr and Mn at energies of 5.48 keV and 5.95 keV, respectively. Faint K beta lines from Ca (4.56 keV) and Fe (7.11 keV) were also seen. The ionization states of Cr and Mn, based on their line centroids, Lire estimated to be similar to that of Fe K alpha (Fe XV or XVI).

    DOI

  • Study of nonthermal emission from SNR RX J1713.7-3946 with Suzaku

    Takaaki Tanaka, Yasunobu Uchiyama, Felix A. Aharonian, Tadayuki Takahashi, Aya Bamba, Junko S. Hiraga, Jun Kataoka, Tetsuichi Kishishita, Motohide Kokubun, Koji Mori, Kazuhiro Nakazawa, Robert Petre, Hiroyasu Tajima, Shin Watanabe

    ASTROPHYSICAL JOURNAL   685 ( 2 ) 988 - 1004  2008.10  [Refereed]

     View Summary

    We present results obtained from a series of observations of the supernova remnant RX J1713.7-3946 by Suzaku. Hard X-rays have been detected up to similar to 40 keV. The hard X-ray spectra are described by a power law with photon indices of similar to 3.0, which is larger than those below 10 keV. The combination of the spatially integrated XIS and HXD spectra clearly reveals a spectral cutoff which is linked to the maximum energy of accelerated electrons. The broad-band coverage of Suzaku allows us to derive, for the first time, the energy spectrum of parent electrons in the cutoff region. The cutoff energy in the X-ray spectrum indicates that the electron acceleration in the remnant proceeds close to the Bohm diffusion limit. We discuss the implications of the spectral and morphological properties of the Suzaku data in the context of the origin of nonthermal emission. The Suzaku X-ray and H.E.S.S. gamma-ray data together hardly can be explained within a pure leptonic scenario. Moreover, the leptonic models require a weak magnetic field, which is inconsistent with the recently discovered X-ray filamentary structures and their short-term variability. The hadronic models with strong magnetic fields provide reasonable fits to the observed spectra, but require special arrangements of parameters to explain the lack of thermal X-ray emission. For morphology studies, we compare the X-ray and TeV gamma-ray surface brightness. We confirm the previously reported strong correlation between X-rays and TeV gamma rays. At the same time, the Suzaku data reveal a deviation from the general tendency, namely, the X-ray emission in the western rims appears brighter than expected from the average X-ray to gamma-ray ratio.

    DOI

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    132
    Citation
    (Scopus)
  • Chandra reveals twin X-ray jets in the powerful FR II radio galaxy 3C 353

    J. Kataoka, L. Stawarz, D. E. Harris, A. Siemiginowska, M. Ostrowski, M. R. Swain, M. J. Hardcastle, J. L. Goodger, K. Iwasawa, P. G. Edwards

    ASTROPHYSICAL JOURNAL   685 ( 2 ) 839 - 857  2008.10  [Refereed]

     View Summary

    We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-Ray Observatory. Due to 3C 353's two 4 '' wide and 2' long jets we are able to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the subarcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the jet and the counterjet, the terminal jet regions (hot spots), and one radio lobe. We show that the detection of the X-ray emission associated with the radio knots and counterknots, which is most likely nonthermal in origin, puts several crucial constraints on the X-ray emission mechanisms in powerful large-scale jets of quasars and FR II sources. In particular, we show that this detection is inconsistent with the inverse-Compton model proposed in the literature and instead implies a synchrotron origin of the X-ray jet photons. We also find that the width of the X-ray counterjet is possibly narrower than that measured in radio bands, that the radio to X-ray flux ratio decreases systematically downstream along the jets, and that there are substantial (kpc-scale) offsets between the positions of the X-ray and radio intensity maxima within each knot, whose magnitudes increase away from the nucleus. We discuss all these findings in the wider context of the physics of extragalactic jets, proposing some particular although not definitive solutions or interpretations for each problem. In general, we find that the synchrotron X-ray emission of extragalactic large-scale jets is not only shaped by the global hydrodynamical configuration of the outflows, but is also likely to be very sensitive to the microscopic parameters of the jet plasma. A complete, self-consistent model for the X-ray emission of extragalactic jets still remains elusive.

    DOI

    Scopus

    36
    Citation
    (Scopus)
  • Suzaku view of powerful gamma-ray quasars

    Jun Kataoka

    International Journal of Modern Physics D   17 ( 9 ) 1483 - 1489  2008.09

     View Summary

    We present the results from multiwavelength campaigns of three powerful gamma-ray quasars, PKS 1510-089, RBS 315 and Swift J0746.3+2548, recently organized with Suzaku. The Suzaku observation provided one of the highest S/N X-ray spectra ever reported between 0.3 and 50 keV. For these quasars, the X-ray spectrum is well represented by an extremely hard power-law with photon index Γ ≃ 1.2, but is augmented by an additional soft component apparently below 1 keV for PKS 1510-089, whereas a strong deficit of soft photons is observed in RBS 315. We model the broadband spectra of these powerful quasars and argue that the power of the jet is dominated by protons but with the number of electrons/positrons exceeding the number of protons by a factor ≃ 10. We also argue that an extremely hard X-ray spectra may result from a double power-law form of the injected electrons, with the break energy γbr ≃ 1000 corresponding to the anticipated threshold of diffusive shock acceleration. © 2008 World Scientific Publishing Company.

    DOI

    Scopus

  • PoGOLite - A high sensitivity balloon-borne soft gamma-ray polarimeter

    Tuneyoshi Kamae, Viktor Andersson, Makoto Arimoto, Magnus Axelsson, Cecilia Marini Bettolo, Claes-Ingvar Bjornsson, Gilles Bogaert, Per Carlson, William Craig, Tomas Ekeberg, Olle Engdegdrd, Yasushi Fukazawa, Shuichi Gunji, Linnea Hjalmarsdotter, Bianca Iwan, Yoshikazu Kanai, Jun Kataoka, Nobuyuki Kawai, Jaroslav Kazejev, Mozsi Kiss, Wlodzimierz Klamra, Stefan Larsson, Grzegorz Madejski, Tsunefumi Mizuno, Johnny Ng, Mark Pearce, Felix Ryde, Markus Suhonen, Hiroyasu TaJima, Hiromitsu Takahashi, Tadayuki Takahashi, Takuya Tanaka, Timothy Thurston, Masaru Ueno, Gary Varneri, Kazuhide Yamamoto, Yuichiro Yamashita, Tomi Ylinen, Hiroaki Yoshida

    ASTROPARTICLE PHYSICS   30 ( 2 ) 72 - 84  2008.09  [Refereed]

     View Summary

    We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200 mCrab point-like sources between 25 and 80 keV in one 6-h flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. Synchrotron radiation, inverse Compton scattering and propagation through high magnetic fields are likely to produce high degrees of polarisation in the energy band of the instrument. We demonstrate, through tests at accelerators, with radioactive sources and through computer simulations, that PoGOLite will be able to detect degrees of polarisation as predicted by models for several classes of high energy sources. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles while securing a large effective area has been the greatest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow Held of view (FWHM = 1.25 msr, 2.0 deg x 2.0 deg) obtained with detector cells and the use of thick background shields warrant a large effective area for polarisation measurements (similar to 228 cm(2) at E = 40 keV) without sacrificing the signal-to-noise ratio. Simulation studies for an atmospheric overburden of 3-4 g/cm(2) indicate that neutrons and gamma-rays entering the PDC assembly through the shields are dominant backgrounds. Off-line event selection based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a similar to 100 mCrab source between 25 and 50 keV. A 6-h observation of the Crab pulsar will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma significance; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. Long-duration flights will measure the dependence of the polarisation across the cyclotron absorption line in Hercules X-1. A scaled-down instrument will be flown as a pathfinder mission from the north of Sweden in 2010. The first science flight is planned to take place shortly thereafter. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

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    46
    Citation
    (Scopus)
  • Suzaku observation of the TeV blazar 1Es 1218+304: Clues on particle acceleration in an extreme TeV blazar

    R. Sato, J. Kataoka, T. Takahashi, G. M. Madejski, S. Ruegamer, S. J. Wagner

    ASTROPHYSICAL JOURNAL LETTERS   680 ( 1 ) L9 - L12  2008.06

     View Summary

    We observed the TeV blazar 1ES 1218 + 304 with the X-ray astronomy satellite Suzaku in 2006 May. At the beginning of the 2 day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of similar to 2 on a timescale of 5 x 10(4) s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft X-rays, with the maximum lag of 2.3 x 10(4) s observed between the 0.3-1 keV and 5-10 keV bands. Furthermore, we discovered that the temporal profile of the flare clearly changes with energy, being more symmetric at higher energies. From the spectral fitting of multiwavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B similar to 0.047 G and an emission region size R = 3.0 x 10(16) cm for an appropriate beaming with a Doppler factor of delta = 20. This value of B is in good agreement with an independent estimate through the model fit to the observed time lag ascribing the energy-dependent variability to the differential acceleration timescale of relativistic electrons provided that the gyrofactor xi is 10(5).

    DOI

    Scopus

    26
    Citation
    (Scopus)
  • Evolution of and high-energy emission from GHz-peaked spectrum sources

    L. Stawarz, L. Ostorero, M. C. Begelman, R. Moderski, J. Kataoka, S. Wagner

    ASTROPHYSICAL JOURNAL   680 ( 2 ) 911 - 925  2008.06  [Refereed]

     View Summary

    Here we discuss evolution and broadband emission of compact (&lt; kpc) lobes in young radio sources. We propose a simple dynamical description for these objects, consisting of a relativistic jet propagating into a uniform gaseous medium in the central parts of an elliptical host. In the framework of the proposed model we follow the evolution of ultra-relativistic electrons injected from a terminal hot spot of a jet to expanding lobes, taking into account their adiabatic energy losses, as well as radiative cooling. This allows us to discuss the broadband lobe emission of young radio sources. In particular, we argue that the observed spectral turnover in the radio synchrotron spectra of these objects cannot originate from the synchrotron self-absorption process but is most likely due to free-free absorption effects connected with neutral clouds of interstellar medium engulfed by the expanding lobes and photoionized by active centers. We also find a relatively strong and complex high-energy emission component produced by inverse Compton upscattering of various surrounding photon fields by the lobes' electrons. We argue that such high-energy radiation is strong enough to account for several observed properties of GHz-peaked spectrum (GPS) radio galaxies at UV- and X-ray frequencies. In addition, this emission is expected to extend up to GeV (or possibly even TeV) photon energies and can thus be probed by several modern gamma-ray instruments. In particular, we suggest that GPS radio galaxies should constitute a relatively numerous class of extragalactic sources detected by GLAST.

    DOI

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    106
    Citation
    (Scopus)
  • Measuring the broad-band X-ray spectrum from 400 eV to 40 keV in the southwest part of the supernova remnant RX J1713.7-3946

    Tadayuki Takahashi, Takaaki Tanaka, Yasunobu Uchiyama, Junko S. Hiraga, Kazuhiro Nakazawa, Shin Watanabe, Aya Bamba, John P. Hughes, Hideaki Katagiri, Jun Kataoka, Motohide Kokubun, Katsuji Koyama, Koji Mori, Robert Petre, Hiromitsu Takahashi, Yoko Tsuboi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   60 ( SPEC. ISS. 1 ) S131 - S140  2008.02  [Refereed]

     View Summary

    We report on results from Suzaku broadband X-ray observations of the southwest part of the galactic supernova remnant (SNR) RX J1713.7-3946 with an energy coverage of 0.4-40keV. The X-ray spectrum, presumably of synchrotron origin, is known to be completely lineless, making this SNR ideally suited for a detailed study of the X-ray spectral shape formed through efficient particle acceleration at high-speed shocks. With a sensitive hard X-ray measurement from the HXD PIN aboard Suzaku, we determined the hard X-ray spectrum in the 12-40 keV range to be described by a power law with photon index of Gamma = 3.2 +/- 0.2, significantly steeper than the soft X-ray index of Gamma = 2.4 +/- 0.05 measured previously with ASCA and other missions. We find that a simple power law fails to describe the full spectral range of 0.4-40 keV, and instead a power-law with an exponential cutoff with a hard index of Gamma = 1.50 +/- 0.09 and a high-energy cutoff of epsilon(c) = 1.2 +/- 0.3 keV formally provides an excellent fit over the full bandpass. If we use the so-called SRCUT model, as an alternative model, it gives a best-fit rolloff energy of epsilon(roll) = 0.95 +/- 0.04 keV. Together with the TeV gamma-ray spectrum, ranging from 0.3 to 100 TeV, recently obtained by HESS observations, our Suzaku observations of RX J1713.7-3946 provide stringent constraints on the highest-energy particles accelerated in a supernova shock.

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  • Development status and simulation study of monitor of all-sky x-ray image (MAXI) mission

    Hiroshi Tomida, Masaru Matsuoka, Kazuyoshi Kawasaki, Shiro Ueno, Yasuki Adachi, Mitsuhiro Kohama, Motoko Suzuki, Masaki Ishikawa, Haruyoshi Katayama, Tatehiro Mihara, Mutsumi Sugizaki, Naoki Isobe, Hiroshi Tsunemi, Emi Miyata, Nobuyuki Kawai, Jun Kataoka, Atsumasa Yoshida, Kazutaka Yamaoka, Hitoshi Negoro, Motoki Nakajima, Yoshihiro Ueda, Satochi Eguchi, Mikio Morii

    Proceedings of SPIE - The International Society for Optical Engineering   7011  2008

     View Summary

    MAXI (Monitor of All-sky X-ray Image) is a payload on board the International Space Station, and will be launched on April 2009. We report on the current development status on MAXI, in particular on the two types of X-ray camera (GSC and SSC), and the simulation results of the MAXI observation. SSC is a CCD camera. The moderate energy resolution enables us to detect the various emission peak including 0.5 keV oxygen line. The averaged energy resolution at the CCD temperature of -70 deg is 144.5 eV (FWHM) for 5.9 keV X-ray. GSC includes proportional gas counters, which have large X-ray detection area (5350cm2). The averaged position resolution of 1.1mm at 8 keV enable us to determined the celestial position of bright sources within the accuracy of 0.1 degree. The simulation study involving the results of performance test exhibits the high sensitivity of MAXI as designed.

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  • Characterizing X-ray variability of TeV blazars

    Jun Kataoka

    Proceedings of Science   63  2008

     View Summary

    In this review, I will discuss how to characterize synchrotron X-ray variability of TeV blazars by using the observed/simulated light curves. Apparently, temporal studies provide independent and complementary information to the spectral studies, but surprisingly little attention has been paid especially for the blazar study. Only exception is a classical argument for presence of “time lag”, which may (or may not) reflect the diffrence of synchrotron cooling timescale. Also very recently, it was suggested that the X-ray variability of TeV blazars indicates a strong red-noise, compared to a fractal, flickering-noise of Seyfert galaxies. Various temporal techniques are proposed in literature, e.g., the power spectrum density (PSD), the structure function (SF), and the discrete correlation function (DCF) and other analysis tools, but special care must be taken if the data are not well sampled and observation is relatively short compared to a characteristic timescale of the system. Also, the situation is being more complicated for low-Earth orbit satellites, e.g., ASCA, RXTE and BeppoSAX, since the light curve inevitably contains “periodic gap” due to the Earth occultation (every 6ksec). I will present detailed approaches to see how the "gap" and the "finite length" of the data affects the results of temporal analysis, and to what extent we can believe in our results. Finally, I will briefly comment on the high-sensitivity X-ray observations with MAXI, that may shed new light on the forthcoming GLAST era.

  • A study of rapid expanding H II region RCW 89

    Y. Yatsu, N. Kawai, J. Kataoka, W. Brinkmann

    AIP Conference Proceedings   983   219 - 221  2008

     View Summary

    In this paper, we present a study of the expanding HII region RCW 89 which is thought to be a part of the radio supernova remnant MSH 15-52 and its associated young 150 ms pulsar B1509-58. We had measured the proper motion of each of the plasma clouds in RCW 89, revealing that these plasma clouds have moved outwards from the SNR center. In order to resolve what is moving at a velocity of ∼5600km/s, we performed spectroscopic analysis of each of the plasma clouds using XMM-Newton and found that each plasma cloud has significantly different redshift. This result strongly suggests that the X-ray emission in RCW 89 comes from the fast expanding SN ejecta. © 2008 American Institute of Physics.

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  • High energy observations of AGN jets and their future prospects

    Jun Kataoka

    AIP Conference Proceedings   1040   191 - 205  2008

     View Summary

    In next five years, dramatic progress is anticipated for the AGN studies, as we have two important missions to observe celestial sources in the high energy regime: GLAST and Suzaku. In this talk, I will summarize recent highlights in studies of AGN jets, focusing on the high-sensitivity X-ray observations that may shed new light on the forthcoming GLAST era. I will especially present some examples from most recent Suzaku observations of blazars, which provides important hints for the shock acceleration in sub-pc scale jets, as well as particle content in jets. Then I will focus on the neutral iron-line feature observed in some broad line radio galaxies, as a probe of jet launching and/or the disk-jet connection. Finally, I will discuss new results of large scale (kpc to Mpc) jets recently resolved with Chandra X-ray observatory. Simultaneous monitoring observations in various wavelengths will be particularly valuable for variable blazar sources, allowing the cross correlations of time series as well as detailed modeling of the spectral evolution between the X-ray and gammaray energy bands. Possible impacts of these new observations across the electromagnetic spectrum on various spatial scales are discussed to challenge the long-standing mystery of AGN jet sources. © 2008 American Institute of Physics.

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  • Beam test results of the polarized gamma-ray observer, PoGOLite

    H. Takahashi, M. Matsuoka, Y. Umeki, H. Yoshida, T. Tanaka, T. Mizuno, Y. Fukazawa, T. Kamae, G. Madejski, H. Tajima, M. Kiss, W. KIamra, S. Larsson, C. Marini Bettolo, M. Pearce, F. Ryde, S. Rydström, K. Kurita, Y. Kanai, M. Arimoto, M. Veno, J. Kataoka, N. Kawai, M. Axelsson, L. Hjalmarsdotter, G. Bogaert, S. Gunji, T. Takahashi, G. Varner, T. Yuasa

    IEEE Nuclear Science Symposium Conference Record     732 - 736  2008

     View Summary

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy range 25-80 keY. During a beam test at KEK-PF in February 2008, 20 detector units were assembled, and a 50 keY X-ray beam with a polarization degree of ∼90% was irradiated at the center unit. Signals from all 20 units were fed into flightversion electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 PDCs, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be ∼34%. These results confirmed the capabilities of both detector and data-acquisition system for a pathfinder flight planned in 2010. ©2008 IEEE.

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  • The MAXI mission operation plan

    Shiro Ueno, Masaru Matsuoka, Kazuyoshi Kawasaki, Hiroshi Tomida, Yasuki Adachi, Mitsuhiro Kohama, Motoko Suzuki, Masaki Ishikawa, Haruyoshi Katayama, Tatehiro Mihara, Mutsumi Sugizaki, Naoki Isobe, Hiroshi Tsunemi, Emi Miyata, Nobuyuki Kawai, Jun Kataoka, Atsumasa Yoshida, Kazutaka Yamaoka, Hitoshi Negoro, Motoki Nakajima, Mikio Morii, Yoshihiro Ueda, Satoshi Eguchi

    Proceedings of SPIE - The International Society for Optical Engineering   7011  2008

     View Summary

    Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky monitor, which will be delivered to the International Space Station (ISS) by a space shuttle crew in early 2009, to scan almost the entire sky once every 96 minutes for a mission life of two to five years. The detection sensitivity will be 5 mCrab (5σ level) for a one-day MAXI operation, 2 mCrab for one week, and 1 mCrab for one month, reaching a source confusion limit of 0.2 mCrab in two years. In this paper, brief descriptions are presented for the MAXI mission and payload, and three operation phases, 1) the launch-to-docking phase, 2) the initial in-orbit calibration phase, and 3) the routine operation phase. We also describes the MAXI data product and its release plan for public users.

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  • Shallow decay phase of X-ray afterglows

    R. Sato, K. Ioka, K. Toma, T. Nakamura, J. Kataoka, N. Kawai, T. Takahashi

    AIP Conference Proceedings   1000   32 - 35  2008

     View Summary

    We investigated the characteristics of the shallow decay phase in the early X-ray afterglows of GRBs observed by Swift X-Ray Telescope (XRT) during the period of January 2005 to December 2006. We found that the intrinsic break time at the shallow-to-normal decay transition in the X-ray light curve T brk0 is moderately well correlated with the isotropic X-ray luminosity in the end of the shallow decay phase (LX,end) as Tbrk0=(9.39±0.64)×103s(L X,end/1047ergsṡs-1) -0.71±0.03. Using Tbrk0-L X,end relation we have determined the pseudo redshifts of 33 GRBs. We compared the pseudo redshifts of 11 GRBs with measured redshifts and found the rms error to be 0.17 in logz. From this pseudo redshift, we estimate that ∼15% of the Swift GRBs have z>5. The advantages of this distance indicator is that (1) it requires only X-ray afterglow data while other methods such as Amati and Yonetoku correlations require the peak energy (Ep) of the prompt emission, (2) the redshift is uniquely determined without redshift degeneracies unlike the Amati correlation, and (3) the redshift is estimated in advance of deep follow-ups so that possible high redshift GRBs might be selected for detailed observations. © 2008 American Institute of Physics.

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  • Performance and current status of Monitor of All-sky X-ray Image on the International Space Station

    M. Suzuki, M. Matsuoka, K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa, H. Katayama, T. Mihara, N. Isobe, H. Tsunemi, E. Miyata, H. Negoro, M. Nakajima, N. Kawai, J. Kataoka, A. Yoshida, K. Yamaoka, M. Morii

    AIP Conference Proceedings   1000   592 - 595  2008

     View Summary

    Monitor of All-sky X-ray Image (MAXI) will be launched and attached on the International Space Station (ISS) next year. MAXI scans the sky while ISS goes around the Earth and provides an all sky X-ray image every orbit. MAXI has two types of X-ray instruments: gas-proportional counters for 2-30 keV and CCD cameras for 0.5-10 keV. MAXI will be able to transmit alerts to the Internet on X-ray transients including bright X-ray afterglows. © 2008 American Institute of Physics.

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  • X-ray polarimetry small satellite TSUBAME

    Arimoto Makoto, Tsubuku Yoshihiro, Toizumi Takahiro, Kobayashi Mitsuyoshi, Yatsu Yoichi, Shimokawabe Takashi, Kataoka Jun, Kawai Nobuyuki, Omagari Kuniyuki, Fujiwara Ken, Konda Yasumi, Tanaka Yohei, Maeno Masaki, Yamanaka Tomio, Ashida Hiroki, Nishida Junichi, Fujihashi Kouta, Ikeda Takuro, Inagawa Shinichi, Miura Yoshiyuki, Matunaga Saburo

    GAMMA-RAY BURSTS 2007   1000   607 - +  2008

     View Summary

    TSUBAME is a university-built small satellite mission to measure polarization of hard X-ray photons (30-100 keV) from Gamma-ray bursts (GRBs) using azimuthal angle anisotropy of Compton-scattered photons. Polarimetry in the hard X-ray and soft γ-ray band plays a crucial role in the understanding of high energy emission mechanisms and the distribution of magnetic fields and radiation fields. TSUBAME has two instruments: the Wide-field Bust Monitor (WBM) and the Hard X-ray Compton Polarimeter (HXCP). The WBM determines on board the direction of the burst occurrence with an accuracy of 10 degrees, then using a high speed attitude control device, the HXCP is pointed to the GRB within 10 seconds after the burst occurrence to promptly detect polarized X-ray photons from the GRB. We present a TSUBAME mission overview, results of a Monte Carlo simulation of the X-ray polarization measurement and the plans for the future of this mission. © 2008 American Institute of Physics.

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  • The PoGOLite balloon-borne soft gamma-ray polarimeter

    Kiss M, Larsson S, Arimoto M, Axelsson A, Bettolo C. Marini, Bogaert G, Floren H. -G, Fukazawa Y, Gunji S, Hjalmarsdotter L, Kamae T, Kanai Y, Kataoka J, Kawai N, Klamra W, Kurita K, Madejski G, Mizuno T, Olofsson G, Pearce M, Ryde F, Rydstrom S, Tajima H, Takahashi H, Takahashi T, Tanaka T, Ueno M, Umeki Y, Varner G, Yoshida H

    COOL DISCS, HOT FLOWS: THE VARYING FACES OF ACCRETING COMPACT OBJECTS   1054   225 - +  2008

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    Linearly polarized radiation in the hard X-ray/soft gamma-ray band is expected from a large variety of astronomical sources. We discuss the importance of polarimetric studies for several classes of sources-pulsars, accreting black holes, magnetic neutron stars and jets from active galaxies-and then describe PoGOLite, a balloon-borne instrument which is currently under construction and will be able to measure the polarization of electromagnetic radiation from such extra-solar objects in the energy range 25-80 keV. © 2008 American Institute of Physics.

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  • Hard X-ray Imager (HXI) for the NeXT mission

    Motohide Kokubun, Kazuhiro Nakazawa, Shin Watanabe, Yasushi Fukazawa, Jun Kataoka, Hideaki Katagiri, Tsunefumi Mizuno, Kazuo Makishima, Masanori Ohno, Goro Sato, Rie Sato, Hiroyasu Tajima, Tadayuki Takahashi, Toru Tamagawa, Takaaki Ta Na Ka, Makoto Tashiro, Hiromitsu Takahashi, Yukikatsu Terada, Yasunobu Uchiyama, Yuji Urata, Kazutaka Yamaoka, Shin'ichiro Takeda, Tetsuichi Kishishita, Masayoshi Ushio, Jun'ichiro Katsuta, Shin'nosuke Ishikawa, Hirokazu Odaka, Hiroyuki Aono, Souichiro Sugimoto, Yuu Koseki, Takao Kitaguchi, Teruaki Enoto, Shin'ya Yamada, Takayuki Yuasa, Tsuyoshi Ueda, Yuichi Uehara, Sho Okuyama, Hajimu Yasuda, Sho Nishino, Yudai Umeki, Katsuhiro Hayashi, Masayuki Matsuoka, Yuki Ikejiri, Akira Endo, Yuichi Yaji, Natsuki Kodaka, Wataru Iwakiri, Tomomi Kouzu, Takako Sugasawara, Atsushi Harayama, Satoshi Nakahira

    Proceedings of SPIE - The International Society for Optical Engineering   7011  2008  [Refereed]

     View Summary

    The Hard X-ray Imager (HXI) is one of three focal plane detectors on board the NeXT (New exploration X-ray Telescope) mission, which is scheduled to be launched in 2013. By use of the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride strip detector, it fully covers the energy range of photons collected with the hard X-ray telescope up to 80 keV with a high quantum efficiency. High spatial resolutions of 400 micron pitch and energy resolutions of 1-2 keV (FWMH) are at the same time achieved with low noise front-end ASICs. In addition, thick BGO active shields compactly surrounding the main detection part, as a heritage of the successful performance of the Hard X-ray Detector (HXD) on board Suzaku satellite, enable to achive an extremely high background reduction for the cosmic-ray particle background and in-orbit activation. The current status of hardware development including the design requirement, expected performance, and technical readinesses of key technologies are summarized.

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  • Multiwavelength observations of the powerful gamma-ray quasar PKS 1510-089: Clues on the jet composition

    J. Kataoka, G. Madejski, M. Sikora, P. Roming, M. M. Chester, D. Grupe, Y. Tsubuku, R. Sato, N. Kawai, G. Tosti, D. Impiombato, Y. Y. Kovalev, Y. A. Kovalev, P. G. Edwards, S. J. Wagner, R. Moderski, L. Stawarz, T. Takahashi, S. Watanabe

    ASTROPHYSICAL JOURNAL   672 ( 2 ) 787 - 799  2008.01

     View Summary

    We present the results from a multiwavelength campaign conducted in 2006 August of the powerful gamma-ray quasar PKS 1510-089 (z = 0.361). This campaign commenced with a deep Suzaku observation lasting 3 days for a total exposure time of 120 ks and continued with Swift monitoring over 18 days. Besides Swift observations, the campaign included ground-based optical and radio data and yielded a quasi-simultaneous broadband spectrum from 10(9) to 10(19) Hz. The Suzaku observation provided a high signal-to-noise ratio X-ray spectrum, which is well represented by an extremely hard power law with a photon index of Gamma similar or equal to 1.2, augmented by a soft component apparent below 1 keV, which is well described by a blackbody model with a temperature of kT similar or equal to 0.2 keV. Monitoring by Suzaku revealed temporal variability that differs between the low- and high-energy bands, again suggesting the presence of a second, variable component in addition to the primary power-law emission. We model the broadband spectrum, assuming that the high-energy spectral component results from Comptonization of infrared radiation produced by hot dust located in the surrounding molecular torus. The adopted internal shock scenario implies that the power of the jet is dominated by protons, but with a number of electrons and/or positrons that exceeds the number of protons by a factor of similar to 10. We also find that inhomogeneities responsible for the shock formation prior to the collision may produce bulk Compton radiation, which can explain the observed soft X-ray excess and possible excess at similar to 18 keV. We note, however, that the bulk Compton interpretation is not unique, as discussed briefly in the text.

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  • Oxygen line mapping of SN 1006 with Suzaku

    Aya Bamba, Hiroya Yamaguchi, KatsuJi Koyama, Junko S. Hiraga, Steve Holt, John P. Hughes, Hideaki Katagiri, Jun Kataoka, Satoru Katsuda, Shunji Kitamoto, Motohide Kokubun, Hironori Matsumoto, Emi Miyata, Koji Mori, Hiroshi Nakajima, Masanobu Ozaki, Rob Petre, Akiko Sekiguchi, Tadayuki Takahashi, Takaaki Tanaka, Yukikatsu Terada, Hiroshi Tomida, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Yasunobu Uchiyama, Masaru Ueno, Shin Watanabe

    ADVANCES IN SPACE RESEARCH   41 ( 3 ) 411 - 415  2008  [Refereed]

     View Summary

    SN 1006 is one of the supernova remnants (SNRs) with relatively low-temperature electrons, considering the young age of just 1000 years. We carried out SN 1006 mapping observations with the X-ray Imaging Spectrometers (XIS) and the Hard X-ray Detector (HXD) onboard Suzaku, the fifth Japanese X-ray satellite. Thanks to the excellent spectral resolution of XIS in the soft X-ray band, H-like and He-like oxygen emission lines were clearly detected, and we could make a map of the line intensity, and as well as a flux and the photon index of nonthermal component. We found that these parameters have spatial dependences from region to region in the SNR; the north region is bright in nonthermal, while dim in thermal; the east region is bright in both nonthermal and thermal; the inner region shows dim nonthermal and bright thermal emission. The photon index is the smallest in the north region. (C) 2007 Published by Elsevier Ltd on behalf of COSPAR.

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  • Environmental tests of the flight GLAST LAT tracker towers

    R. Bagagli, L. Baldini, R. Bellazzini, G. Barblellini, F. Belli, T. Borden, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, J. Goodman, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, J. Ku, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, B. Marangelli, F. Marcucci, M. Marchetti, M. M. Massai, M. N. Mazziotta, M. Minori, M. Minuti, N. Mirizzi, M. Mongelli, C. Monte, A. Morselli, D. Nelson, M. Nordby, N. Omodei, M. Pepe, M. Pesce-Rollins, S. Raino, R. Rando, M. Razzano, D. Rich, G. Scolieri, C. Sgro, G. Spandre, P. Spinelli, M. Sugizaki, H. Takahashi, A. Tenze, C. Young

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   584 ( 2-3 ) 358 - 373  2008.01  [Refereed]

     View Summary

    The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance. (C) 2007 Elsevier B.V. All rights reserved.

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  • In-flight status of the X-ray observatory Suzaku

    T. Dotani, K. Mitsuda, M. Bautz, H. Inoue, R. L. Kelley, K. Koyama, H. Kunieda, K. Makishima, Y. Ogawara, R. Petre, T. Takahashi, H. Tsunemi, N. E. White, N. Anabuki, L. Angelini, K. Arnaud, H. Awaki, A. Bamba, K. Boyce, G. V. Brown, K. W. Chan, J. Cottam, J. Doty, K. Ebisawa, Y. Ezoe, A. C. Fabian, E. Figueroa, R. Fujimoto, Y. Fukazawa, T. Furusho, A. Furuzawa, K. Gendreau, R. E. Griffiths, Y. Haba, K. Hamaguchi, I. Harrus, G. Hasinger, I. Hatsukade, K. Hayashida, P. J. Henry, J. S. Hiraga, S. S. Holt, A. Hornschemeier, J. P. Hughes, U. Hwang, M. Ishida, Y. Ishisaki, N. Isobe, M. Itoh, N. Iyomoto, S. M. Kahn, T. Kamae, H. Katagiri, J. Kataoka, H. Katayama, N. Kawai, M. Kawaharada, C. Kilbourne, K. Kinugasa, S. Kissel, S. Kitamoto, M. Kohama, T. Kohmura, M. Kokubun, T. Kotani, J. Kotoku, A. Kubota, G. M. Madejski, Y. Maeda, F. Makino, A. Markowitz, C. Matsumoto, H. Matsumoto, M. Matsuoka, K. Matsushita, D. McCammon, T. Mihara, K. Misaki, E. Miyata, T. Mizuno, K. Mori, H. Mori, M. Morii, H. Moseley, K. Mukai, H. Murakami, T. Murakami, R. Mushotzky, F. Nagase, M. Namiki, H. Negoro, K. Nakazawa, J. A. Nousek, T. Okajima, Y. Ogasaka, T. Ohashi, T. Oshima, N. Ota, M. Ozaki, H. Ozawa

    IEEE Nuclear Science Symposium Conference Record   4   2526 - 2531  2007.12  [Refereed]

     View Summary

    We report in-flight status of the X-ray detectors on board the Suzaku observatory, the 5th X-ray astronomy satellite of Japan launched on July 10, 2005. Suzaku is equipped with two types of Instruments: one is the X-ray Imaging Spectrometers (XISs) and the other is Hard X-ray Detector (HXD). XIS utilizes the X-ray CCD camera in combination with the grazing-incidence X-ray telescope. HXD is a non-imaging, hybrid detector utilizing Si PIN diodes and GSO/BGO phoswich counters. Suzaku takes a low-earth, circular orbit with an altitude of 560 km and an inclination of 31 deg. This means that Suzaku goes through the south atlantic anomaly about 1/3 of its revolutions. This has a large impact on the in-flight performance of XIS and HXD, which is reported in detail in the present paper. © 2007 IEEE.

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  • Temperature effects in reverse-type avalanche photodiodes

    Mitsuhiro Sato, Takayuki Yanagida, Akira Yoshikawa, Yoichi Yatsu, Jun Kataoka, Fumio Saito

    IEEE Nuclear Science Symposium Conference Record   2   1491 - 1493  2007.12

     View Summary

    These The present paper shows ionization coefficient ratios, k-values, k1and keff, of reverse-type Si avalanche photodiode. Both of keffand k1, tend to increase when APDs are cooled down. The results for keffare 0.0023 ± 0.0002 at 20 °C, 0.0027 ± 0.0003 at 0 °C, and 0.0049 ±0.0007 at -20 °C. With the result of k1, temperature dependency of k-values Indicates mean free paths of the carriers for phonon scattering shows different temperature dependency, which is considered to reflect the inner structure of APDs. © 2007 IEEE.

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  • Hole multiplication in a reverse-type avalanche photodiode

    Mitsuhiro Sato, Takayuki Yanagida, Akira Yoshikawa, Yoichi Yatsu, Jun Kataoka, Fumio Saito

    IEEE Nuclear Science Symposium Conference Record   2   1486 - 1490  2007.12

     View Summary

    This paper reports on hole multiplication processes, detected in a reverse-type avalanche photodiode (APD), Hamamatsu Photonics type S8664-55, which has a light sensitive area of 5 × 5 mm and a depletion layer thickness of ∼ 40 μm. When the APD was irradiated from a Am isotope, the 13.9 keV and 17.6 keV X-rays produced spectral peaks, whose pulse height depended strongly on the bias voltage, whereas 57.5 keV photons produced another peak, whose the pulse height was much less bias sensitive. The former are identified with electron multiplication signals, whereas the latter with those due to hole multiplication. By measuring the electron and hole multiplication gains as a function of the bias voltage, the ratio of hole and electron ionization probabilities was determined as 0.0130 ± 0.0010 at 20 °C, and 0.0153 ±0.0010 at -20 °C. © 2007 IEEE.

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  • Reverse-type avalanche photodiode for scintillation detection and intrinsic energy resolution of BGO and GSO:Ce

    Mitsuhiro Sato, Takayuki Yanagida, Akira Yoshikawa, Yousuke Yatsu, Jun Kataoka, Yoshitaka Ishikawa, Fumio Saito

    IEEE Nuclear Science Symposium Conference Record   3   2023 - 2032  2007.12

     View Summary

    In this paper we present a summary of a study of reverse-type avalanche photodiodes (APDs) used as scintillation detectors for X- and γ-ray spectroscopy. The energy resolution of the APDs was evaluated by varying the avalanche gain, M, in the range from 1 to 200. The best energy resolution recorded for the 662 keV137Cs γ-ray photoabsorption peak was 8.3 ± 0.5 % using a 5 × 5 × 5 mm3BGO crystal coupled to a S8664-55 APD with a 5 × 5 mm2light sensitive window, manufactured by Hamamatsu Photonics, Inc. The measurement was made with a gain of 20 and at a temperature of -20 °C. The main advantage of this method is that an accurate value for the intrinsic resolution of the crystal can be easily obtained by subtracting the contribution to the energy resolution from circuit noise and the electron-hole pair statistics. The intrinsic energy resolution of the BGO crystal sample at 662 keV was found to be 6.5 ± 0.5%. The observed intrinsic energy resolution of BGO as a function of energy shows the same relationship as that shown in other published works. With this method the intrinsic energy resolution of GSO (Ce 0.5 % mol) was also measured. While the intrinsic energy resolution of BGO shows an energy dependence proportional to E-1/2, GSO has a step-like characteristic, with the energy resolution increasing from ∼100 keV up to ∼500 keV. © 2007 IEEE.s.

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  • Performance assessment study of the balloon-borne astronomical soft gamma-ray polarimeter PoGOLite

    Arimoto M, Kanai Y, Ueno M, Kataoka J, Kawai N, Tanaka T, Yamamoto K, Takahashi H, Mizuno T, Fukazawa Y, Axelsson M, Kiss M, Bettolo C. Marini, Carlson P, Klamra W, Pearce M, Chen P, Craig B, Kamae T, Madejski G, Ng J. S. T, Rogers R, Tajima H, Thurston T. S, Saito Y, Takahashi T, Gunji S, Bjornsson Ca, Larsson S, Ryde F, Bogaert G, Varner G

    PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES   40 ( 2 ) 438 - 441  2007.12  [Refereed]

     View Summary

    Measurements of polarization play a crucial role in the understanding of the dominant emission mechanism of astronomical sources. Polarized Gamma-ray Observer-Light version (PoGOLite) is a balloon-borne astronomical soft gamma-ray polarimeter at the 25-80 keV band. The PoGOLite detector consists of a hexagonal close-packed array of 217 Phoswich detector cells (PDCs) and side anti-coincidence shields (SASs) made of BGO crystals surrounding PDCs. Each PDC consists of a slow hollow scintillator, a fast scintillator and a BGO crystal that connects to a photomultiplier tube at the end. To examine the PoGOLite's capability and estimate the performance, we conducted experiments with the PDC using radioisotope 241Am. In addition, we compared this result with performance expected by Monte Carlo simulation with Geant4. As a result, we found that the actual PDC has the capability to detect a 100 m Crab source until 80 keV. © 2007 Elsevier B.V. All rights reserved.

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  • Design and initial tests of the Tracker-converter of the Gamma-ray Large Area Space Telescope

    W. B. Atwood, R. Bagagli, L. Baldini, R. Bellazzini, G. Barbiellini, F. Belli, T. Borden, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, R. Giannitrapani, N. Giglietto, F. Giordano, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, M. M. Massai, M. N. Mazziotta, M. Minuti, T. Mizuno, A. Morselli, D. Nelson, M. Nordby, T. Ohsugi, N. Omodei, M. Ozaki, M. Pepe, S. Raino, R. Rando, M. Razzano, D. Rich, H. F. -W. Sadrozinski, G. Scolieri, C. Sgro, G. Spandre, P. Spinelli, M. Sugizaki, H. Tajima, H. Takahashi, T. Takahashi, S. Yoshida, C. Young, M. Ziegler

    ASTROPARTICLE PHYSICS   28 ( 4-5 ) 422 - 434  2007.12  [Refereed]

     View Summary

    The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. It is the largest silicon-strip detector system ever built for launch into space, and its aggressive design emphasizes very low power consumption, passive cooling, low noise, high efficiency, minimal dead area, and a structure that is highly transparent to charged particles. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements. It is now installed in the completed LAT, which is being prepared for launch in early 2008. (c) 2007 Elsevier B.V. All rights reserved.

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  • Construction, test and calibration of the GLAST silicon tracker

    C. Sgro, W. B. Atwood, L. Baldini, G. Barbiellini, R. Bellazzini, F. Belli, E. Bonamente, T. Borden, J. Bregeon, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, M. M. Massai, M. N. Mazziotta, M. Minuti, T. Mizuno, A. Morselli, D. Nelson, M. Nordby, T. Ohsugi, N. Omodei, M. Ozaki, M. Pepe, S. Raino, R. Rando, M. Razzano, D. Rich, H. F. -W. Sadrozinski, G. Scolieri, G. Spandre, P. Spinelli, M. Sugizaki, H. Tajima, H. Takahashi, T. Takahashi, S. Yoshida, C. Young, M. Ziegler

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   583 ( 1 ) 9 - 13  2007.12  [Refereed]

     View Summary

    The Gamma-ray Large Area Space Telescope represents a great advance in space application of silicon detectors. With a surface of 80 m(2) and about 1 M readout channels it is the largest silicon tracker ever built for a space experiment.
    GLAST is an astro-particle mission that will study the mostly unexplored, high energy (20 MeV-300 GeV) spectrum coming from active sources or diffused in the Universe. The detector integration and test phase is complete. The full instrument underwent environmental testing and the spacecraft integration phase has just started: the launch is foreseen in late 2007. In the meanwhile the spare modules are being used for instrument calibration and performance verification employing the CERN accelerator complex. A Calibration Unit has been exposed to photon, electron and hadron beams from a few GeV up to 300 GeV. We report on the status of the instrument and on the calibration campaign. (C) 2007 Elsevier B.V. All rights reserved.

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    3
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  • Measuring energy dependent polarization in soft gamma-rays using compton scattering in PoGOLite

    M. Axelsson, O. Engdegard, F. Ryde, S. Larsson, M. Pearce, L. Hjalmarsdotter, M. Kiss, C. Marini Bettolo, M. Arimoto, C. -I. Bjornsson, P. Carlson, Y. Fukazawa, T. Kamae, Y. Kanai, J. Kataoka, N. Kawal, W. Klamra, G. Madejski, T. Mizuno, J. Ng, H. Tajima, T. Takahashi, T. Tanaka, M. Ueno, G. Varner, K. Yamamoto

    ASTROPARTICLE PHYSICS   28 ( 3 ) 327 - 337  2007.11  [Refereed]

     View Summary

    Linear polarization in X-and gamma-rays is an important diagnostic of many astrophysical sources, foremost giving information about their geometry, magnetic fields, and radiation mechanisms. However, very few X-ray polarization measurements have been made, and then only mono-energetic detections, whilst several objects are assumed to have energy dependent polarization signatures. In this paper, we investigate whether detection of energy dependent polarization from cosmic sources is possible using the Compton technique, in particular with the proposed PoGOLite balloon-experiment, in the 25-100 keV range. We use Geant4 simulations of a PoGOLite model and input photon spectra based on Cygnus X-1 and accreting magnetic pulsars (100 mCrab). Effective observing times of 6 and 35 h were simulated, corresponding to a standard and a long duration flight, respectively. Both smooth and sharp energy variations of the polarization are investigated and compared to constant polarization signals using chi-square statistics. We can reject constant polarization, with energy, for the Cygnus X-1 spectrum (in the hard state), if the reflected component is assumed to be completely polarized, whereas the distinction cannot be made for weaker polarization. For the accreting pulsar, constant polarization can be rejected in the case of polarization in a narrow energy band with at least 50% polarization, and similarly for a negative step distribution from 30% to 0% polarization. (c) 2007 Elsevier B.V. All rights reserved.

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    6
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  • Development of wideband X-ray and gamma-ray spectrometer using transmission-type, large-area APD

    S. Tanaka, J. Kataoka, Y. Kanai, Y. Yatsu, M. Arimoto, M. Koizumi, N. Kawai, Y. Ishikawa, S. Kawai, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   582 ( 2 ) 562 - 568  2007.11  [Refereed]

     View Summary

    The avalanche photodiode (APD) is a high-performance and compact light sensor recently applied in various fields of experimental physics. Among several types of APDs, the reach-through APD offers an advantage in direct X-ray detection, thanks to its thick depletion layer (&gt;= 100 mu m) in front of the amplification region. This type of APD is also sensitive to weak scintillation light from gamma ray scintillators with a high quantum efficiency of similar to 80% (at lambda similar or equal to 500 nm). In this paper, we propose a novel design of a compact X-rayto-gamma-ray detector widely applicable between 1 keV and several hundreds of keV. The prototype consists of a reach-through APD (transmission type) optically coupled with a cubic CsI(T1) crystal 4 x 4 x 4mm(3) in size. By applying the pulse shape discrimination technique to the APD output, we successfully discriminated the X-ray signals directly detected within the APD (1-40 keV), and gamma ray signals absorbed in a CsI(T1) scintillator (10-800 keV) located immediately behind the APD. Optimum FWHM energy resolutions of 15.1 +/- 0.2%, 6.6 +/- 0.4%, and 7.6 +/- 0.1% were obtained for 5.9 keV X-rays, 32 keV X-rays, and 662 keV gamma rays, respectively, measured at +20 degrees C. This stacked configuration is viable for various future applications in space science and nuclear medicine. (c) 2007 Elsevier B.V. All rights reserved.

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    11
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  • The Suzaku observation of the nucleus of the radio-loud active galaxy Centaurus A: Constraints on abundances of the accreting material

    A. Markowitz, T. Takahashi, S. Watanabe, K. Nakazawa, Y. Fukazawa, M. Kokubun, K. Makishima, H. Awaki, A. Bamba, N. Isobe, J. Kataoka, G. Madejski, R. Mushotzky, T. Okajima, A. Ptak, J. N. Reeves, Y. Ueda, T. Yamasaki, T. Yaqoob

    ASTROPHYSICAL JOURNAL   665 ( 1 ) 209 - 224  2007.08  [Refereed]

     View Summary

    A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3-250 keV. The net exposure times after screening were 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X- ray Detector (HXD) PIN, and 17.1 ks for the HXD GSO. The hard X- rays are fit by two power laws of the same slope, absorbed by columns of 1.5 and 7 x 10(23) cm(-2), respectively. The spectrum is consistent with previous suggestions that the power-law components are X- ray emission from the subparsec VLBI jet and from Bondi accretion at the core, but it is also consistent with a partial-covering interpretation. The soft band is dominated by thermal emission from the diffuse plasma and is fit well by a two-temperature VAPEC model, plus a third power-law component to account for scattered nuclear emission, jet emission, and emission from X- ray binaries and other point sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca, and Ni are detected. The Fe K proportional to line width yields a 200 lt-day lower limit on the distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell absorption edges are detected. Elemental abundances are constrained via absorption edge depths and strengths of the fluorescent and diffuse plasma emission lines. The high metallicity ([Fe/H] = +0.1) of the circumnuclear material suggests that it could not have originated in the relatively metal-poor outer halo unless enrichment by local star formation has occurred. Relative abundances are consistent with enrichment from Type II and Ia supernovae.

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  • Low-energy cutoffs and hard X-ray spectra in high-z radio-loud quasars: The Suzaku view of RBS 315

    F. Tavecchio, L. Maraschi, G. Ghisellini, J. Kataoka, L. Foschini, R. M. Sambruna, G. Tagliaferri

    ASTROPHYSICAL JOURNAL   665 ( 2 ) 980 - 989  2007.08  [Refereed]

     View Summary

    We present the results from the Suzaku observation of the powerful radio-loud quasar RBS 315 (z = 2.69), for which a previous XMM-Newton observation showed an extremely flat X-ray continuum up to 10 keV ( photon index Gamma = 1.26) and indications of strong intrinsic absorption (N-H similar to 10(22) cm(-2), assuming neutral gas). The instrument for hard X-rays, HXD/PIN, allows us a detection of the source up to 50 keV. The broadband continuum (0.5-50 keV) can be well modeled with a power law with slope Gamma = 1.5 (definitively softer than the continuum measured by XMM-Newton) above 1 keV with strong deficit of soft photons. The low-energy cutoff can be well fitted, either with intrinsic absorption ( with column density N-H similar to 10(22) cm(-2) in the quasar rest frame) or with a break in the continuum, with an extremely hard (Gamma = 0.7) power law below 1 keV. We construct the spectral energy distribution of the source, using also optical-UV measurements obtained through a quasi-simultaneous observation with UVOT on board Swift observation. The shape of the SED is similar to that of other flat-spectrumradio quasars (FSRQs) with similar power, making this source an excellent candidate for the detection in gamma-rays by the Gamma-Ray Large Area Space Telescope ( GLAST). We model the SED with the synchrotron inverse Compton model usually applied to FSRQs, showing that the deficit of soft photons can be naturally interpreted as due to an intrinsic curvature of the spectrum near the low-energy end of the IC component, rather than to intrinsic absorption, although the latter possibility cannot be ruled out. We propose that in at least a fraction of the radio-loud QSOs at high redshift, the cutoff in the soft X-ray band can be explained in a similar way. Further studies are required to distinguish between the two alternatives.

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    50
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  • Probing the disk-jet connection of the radio galaxy 3C 120 observed with Suzaku

    Jun Kataoka, James N. Reeves, Kazushi Iwasawa, Alex G. Markowitz, Richard F. Mushotzky, Makoto Arimoto, Tadayuki Takahashi, Yoshihiro Tsubuku, Masayoshi Ushio, Shin Watanabe, Luigi C. Gallo, Greg M. Madejski, Yuichi Terashima, Naoki Isobe, Makoto S. Tashiro, Takayoshi Kohmura

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 2 ) 279 - 297  2007.04  [Refereed]

     View Summary

    We report on deep (40 ks x 4) observations of the bright broad line radio galaxy 3C 120 using Suzaku. The observations were spaced one week apart, and sampled a range of continuum fluxes. An excellent broadband spectrum was obtained over two decades of frequency (0.6 to 50 keV) within each 40 ks exposure. We clearly resolved the iron K emission-line complex, finding that it consists of a narrow K alpha core (sigma similar or equal to 110 eV or an EW of 60 eV), a 6.9 keV line, and an underlying broad iron line. Our confirmation of the broad line contrasts with the XMM-Newton observation in 2003, where the broad line was not required. The most natural interpretation of the broadline is iron Kline emission from a face-on accretion disk that is truncated at similar to 10 r(g). Above 10 keV, a relatively weak Compton hump was detected (reflection fraction of R similar or equal to 0.6), superposed on the primary X-ray continuum of Gamma similar or equal to 1.75. Thanks to the good photon statistics and low background of the Suzaku data, we clearly confirm the spectral evolution of 3C 120, whereby the variability amplitude decreases with increasing energy. More strikingly, we discovered that the variability is caused by a steep power-law component of Gamma similar or equal to 2.7, possibly related to non-thermal jet emission. We discuss our findings in the context of similarities and differences between radio-loud/quiet objects.

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  • 22pZJ-14 Development of softwares of GSC on Monitor of All-sky X-ray Image

    Suzuki Motoko, Matsuoka Masaru, Kawasaki Kazuyoshi, Ueno Shiro, Tomida Hiroshi, Ishikawa Masaki, Kohama Mitsuhiro, Miyakawa Takehiro, Mihara Tatehiro, Isobe Naoki, Kawai Nobuyuki, Kataoka Jun, Tanaka Satoshi, Yoshida Atsumasa, Negoro Hitoshi, Nakajima Motoki, Morii Mikio

    Meeting Abstracts of the Physical Society of Japan   62.2.1   111  2007

    DOI CiNii

  • A Suzaku observation of the low-ionization Fe-line emission from RCW 86

    Masaru Ueno, Rie Sato, Jun Kataoka, Ilana Harrus, Robert Petre

    Progress of Theoretical Physics Supplement   ( 169 ) 84 - 87  2007

     View Summary

    The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant (SNR) RCW 86 in February 2006 to study the nature of the 6.4 keV emission line. The new data localize it for the first time; most of the line emission is adjacent and interior to the forward shock and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line that we interpret as the Kβ emission from low-ionization iron. The Fe-K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with net > 109 cm-3 s and kTe ∼ 5 keV. This combination of low net and high kTe suggests collisionless electron heating in an SNR shock. The Fe Ka line shows evidence for intrinsic broadening, with a width of 47 (34-59) eV (99% error region). The difference of the spatial distributions of the hard continuum above 3 keV and the Fe-K line emission support a synchrotron origin for the hard continuum.

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  • Millenium study of SN 1006 with Suzaku

    Aya Bamba, Hiroya Yamaguchi, Katsuji Koyama, Junko S. Hiraga, Steve Holt, John P. Hughes, Hideaki Katagiri, Jun Kataoka, Shunji Kitamoto, Motohide Kokubun, Hironori Matumoto, Emi Miyata, Koji Mori, Hiroshi Nakajima, Masanobu Ozaki, Robert Petre, Akiko Sekiguchi, Tadayuki Takahashi, Takaaki Tanaka, Yukikatsu Terada, Hiroshi Tomida, Hiroshi Tsunemi, Yohko Tsuboi, Masahiro Tsujimoto, Yasunobu Uchiyama, Masaru Ueno, Shin Watanabe

    Progress of Theoretical Physics Supplement   ( 169 ) 142 - 145  2007

     View Summary

    SN 1006 is the milestone of understanding the acceleration mechanism of cosmic rays, and this year is the millennium year for the remnant. We carried out SN 1006 mapping observations with the X-ray Imaging Spectrometers (XIS) onboard Suzaku satellite. Thanks to the excellent spectral response of XIS, K emission lines from highly ionized oxygen were clearly resolved. The intensity maps of these lines have been made additional to the intensity and photon index maps of the nonthermal component. We discovered that regions with strong and hard nonthermal component has weak thermal emission. The north rim of the SNR has the hardest nonthermal component. These facts might have information of efficient cosmic ray acceleration and background plasma.

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  • Wide-range multiwavelength observations of northern TeV blazars with MAGIC/HESS, Suzaku and KVA

    M. Hayashida, S. Rügamer, D. Mazin, R. Firpo, K. Mannheim, F. Tavecchio, M. Teshima, D. Horns, L. Costamante, S. Schwarzburg, S. Wagner, T. Takahashi, J. Kataoka, G. Madejski, R. Sato, M. Ushio

    Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007   3 ( OG PART 2 ) 1029 - 1032  2007

     View Summary

    We conducted multiwavelength observations of the northern TeV blazars, Mkn501 and Mkn421, employing the ground-based γ-ray telescopes MAGIC and HESS, the Suzaku X-ray satellite and the KVA optical telescope. The observations for Mkn501 were performed in July 2006. The source showed one of the lowest fluxes both in very high energy (VHE) γ-ray and X-ray. No significant flux variability could be found in the VHE band while an overall increase of about 50% on a 1-day time scale could be seen in the light curve of the X-ray flux. A one-zone synchrotron self-Compton model can well describe our simultaneous spectral data of the VHE γ-ray and the X-ray emissions of Mkn501 in the quiescent state. The simultaneous observations of Mkn421 were carried out in April 2006. The source was clearly detected in all observations and showed a high state of activity both in VHE γ-ray and X-ray.

  • An overview of MAXI onboard JEM-EF of the international space station

    M. Matsuoka, K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa, H. Katayama, M. Suzuki, T. Miyakawa, T. Mihara, N. Isobe, H. Tsunemi, E. Miyata, H. Negoro, M. Nakajima, N. Kawai, J. Kataoka, A. Yoshida, K. Yamaoka, M. Morii

    Proceedings of SPIE - The International Society for Optical Engineering   6686  2007

     View Summary

    MAXI is the first payload to be attached on JEM-EF (Kibo exposed facility) of ISS. It provides an all sky X-ray image every ISS orbit. If MAXI scans the sky during one week, it could make a milli-Crab X-ray all sky map excluding bright region around the sun. Thus, MAXI does not only inform X-ray novae and transients rapidly to world astronomers if once they occur, but also observes long-term variability of Galactic and extra-Galactic X-ray sources. MAXI also provides an X-ray source catalogue at that time with diffuse cosmic X-ray background. MAXI consists of two kinds of detectors, position sensitive gas-proportional counters for 2-30 keV X-rays and CCD cameras for 0.5-10 keV X-rays. All instruments of MAXI are now in final phase of pre-launching tests of their flight modules. We are also carrying out performance tests for X-ray detectors and collimators. Data processing and analysis software including alert system on ground are being developed by mission team. In this paper we report an overview of final instruments of MAXI and capability of MAXI.

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  • High sensitivity all sky X-ray monitor and survey with MAXI

    N. Isobe, T. Mihara, M. Kohama, M. Suzuki, M. Matsuoka, S. Ueno, H. Tomida, N. Kawai, J. Kataoka, A. Yoshida, K. Yamaoka, H. Tsunemi, E. Miyata, H. Negoro, M. Nakajima, M. Morii

    AIP Conference Proceedings   921   440 - 441  2007

     View Summary

    MAXI is an all sky X-ray monitor to be mounted on the Japanese Experimental Module in the International Space Station (ISS). It scans almost all over the sky every 96 minutes, in the course of the orbital motion of the ISS. MAXI is designed to have a sensitivity, significantly higher than the previous X-ray monitors, and then, to detect X-ray sources as faint as 1 mCrab in a week observation. Therefore, MAXI is expected to create a novel catalogue of not only the stable X-ray sources but also the highly variable ones in the sky, especially active galactic nuclei for the first time. If MAXI detects X-ray phenomena, alerts will be quickly made through the Internet. © 2007 American Institute of Physics.

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  • Suzaku observations of AGN and synergy with GLAST

    Jun Kataoka, Tad Takahashi, Greg Madejski

    AIP Conference Proceedings   921   89 - 91  2007

     View Summary

    In next five years, dramatic progress is anticipated for the AGN studies, as we have two important missions to observe celestial sources in the high energy regime: GLAST and Suzaku. Suzaku is the 5th Japanese X-ray astronomy satellite which was successfully launched in July 2005. It carries four X-ray sensitive imaging CCD cameras (0.2-12 keV) located in the focal planes of X-ray telescope, and a non-imaging, collimated hard X-ray detector, which extends the bandpass of the observatory to include the 10-600 keV range. Simultaneous monitoring observations by the two instruments (GLAST and Suzaku) will be particularly valuable for variable radio-loud AGN, allowing the cross-correlations of time series as well as detailed modeling of the spectral evolution between the X-ray and gamma-ray energy bands. In this paper, we show early highlights from Suzaku observations of radio-loud AGNs, and discuss what we can do with GLAST in forthcoming years. © 2007 American Institute of Physics.

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  • Direct and reprocessed gamma-ray emission of kpc-scale jets in FR I radio galaxies

    L. Stawarz, T. M. Kneiske, J. Kataoka

    FIRST GLAST SYMPOSIUM   921   363 - +  2007  [Refereed]

     View Summary

    We discuss the contribution of kiloparsec-scale jets in FR I radio galaxies to the diffuse gamma-ray background radiation. The analyzed gamma-ray emission comes from inverse-Compton scattering of starlight photon fields by the ultrarelativistic electrons whose synchrotron radiation is detected from such sources at radio, optical and X-ray energies. We find that these objects, under the minimum-power hypothesis (corresponding to a magnetic field of 300 mu G in the brightest knots of these jets), can contribute about one percent to the extragalactic gamma-ray background measured by EGRET. We point out that this result already indicates that the magnetic fields in kpc-scale jets of low-power radio galaxies are not likely to be smaller than 10 mu G on average, as otherwise the extragalactic gamma-ray background would be overproduced.

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  • High sensitivity balloon-borne hard X-ray/soft gamma-ray polarimeter PoGOLite

    T. Mizuno, M. Arimoto, M. Axelsson, C. -I. Bjornsson, G. Bogaert, P. Carlson, W. Craig, Y. Fukazawa, S. Gunji, L. Hjalmarsdotter, T. Kamae, Y. Kanai, J. Kataoka, J. Katsuta, N. Kawai, M. Kiss, W. Klamra, S. Larsson, G. Madejski, C. Marini Bettolo, J. Ng M. Pearce, F. Ryde, H. Tajima, H. Takahashi, T. Tanaka, T. Thurston, M. Ueno, G. Varner, H. Yoshida

    2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11   4   2538 - +  2007

     View Summary

    The Polarized Gamma-ray Observer - Lightweight Version (PoGOLite) is a new balloon experiment capable of detecting 10% polarization from a 200 mCrab source in the 25-80 keV energy range in a single 6-hour flight for the first time. Polarization measurements of hard X-rays and soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms as well as source geometries. PoGOLite uses Compton scattering and photo-absorption to measure polarization in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators. The adoption of a well-type phoswich counter concept and a thick polyethylene neutron shield provides a narrow field-of-view (1.25 msr), a large effective area ( &gt;= 250 cm(2) at 40-50 keV), a high modulation factor (more than 25 %) and the low background (- 100 mCrab) required to conduct high-sensitivity polarization measurements. Through tests in laboratories and accelerator facilities of a scaled-down prototype with the front-end electronics of flight design and an extensive study by Monte-Carlo simulation, we have demonstrated high instrument performance. PoGOLite Will be ready for a first engineering flight in 2009 and a science flight in 2010, during which polarization signals from the Crab Nebula/pulsar, Cygnus X-1 and other objects will be observed.

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  • Data acquisition system for the PoGOLite astronomical hard X-ray polarimeter

    T. Tanaka, M. Arimoto, M. Axelsson, C. -I. Bjornsson, G. Bogaert, P. Carlson, M. Cooney, W. Craig, O. Engdegard, Y. Fukazawa, S. Gunji, L. Hjalmarsdotter, T. Kamae, Y. Kanai, J. Kataoka, J. Katsuta, N. Kawai, J. Kazejev, M. Kiss, W. Klamra, S. Larsson, G. Madejski, C. Marini Bettolo, T. Mizuno, J. Ng, M. Nomachi, H. Odaka, M. Pearce, L. Ruckman, F. Ryde, H. Tajima, H. Takahashi, T. Takahashi, T. Thurston, M. Ueno, G. Varner, T. Ylinen, H. Yoshida, T. Yuasa

    2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11   1   445 - 449  2007

     View Summary

    The PoGOLite is a new balloon-borne instrument to measure the polarization of hard X-rays/soft gamma-rays in the 25-80 keV energy range for the first time. In order to detect the polarization, PoGOLite measures the azimuthal angle asymmetry of Compton scattering and the subsequent photo-absorption in an array of detectors. This array consists of 217 well-type phoswich detector cells (PDCs) surrounded by a side anti-coincidence shield (SAS) composed of 54 segments of BGO crystals. At balloon altitude, the intensity of backgrounds due to cosmic-ray charged particles, atmospheric gamma-rays and neutrons is extremely high, typically a few hundred Hz per unit. Hence the data acquisition (DAQ) system of PoGOLite is required to handle more than 270 signals simultaneously, and detect weak signals from astrophysical objects (100mCrab, 1.5 cs(-1) in 25-80 keV) under such a severe environment. We have developed a new DAQ system consisting of front-end electronics, waveform digitizer, Field Programmable Gate Array (FPGA) and a microprocessor. In this system, all output signals of PDC / SAS are fed into individual charge-sensitive amplifier and then digitized to 12 bit accuracy at 24 MSa/s by pipelined analog to digital converters. A DAQ board for the PDC records waveforms which will be examined in an off-line analysis to distinguish signals from the background events and measure the energy spectrum and polarization of targets. A board for the SAS records hit pattern to be used for background rejection. It also continuously records a pulse-height analysis (PHA) histogram to monitor incident background flux. These basic functions of the DAQ system were verified in a series of beam tests.

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  • Reverse-type avalanche photodiode for scintillation detection and intrinsic energy resolution of BGO and GSO : Ce

    Sato Mitsuhiro, Yanagida Takayuki, Yoshikawa Akira, Yatsu Yousuke, Kataoka Jun, Ishikawa Yoshitaka, Saito Fumio, IEEE

    2007 Ieee Nuclear Science Symposium Conference Record, Vols 1-11     2023 - 2032  2007  [Refereed]

  • Suzaku observation of TeV SNR RX J1713.7-3946

    Takahashi T, Tanaka T, Uchiyama Y, Hiraga J.S, Nakazawa K, Watanabe S, Bamba A, Hughes J.P, Katagiri H, Kataoka J, Kokubun M, Koyama K, Mori K, Petre R, Takahashi H, Tsuboi Y

    Progress of Theoretical Physics Supplement   ( 169 ) 157 - 161  2007  [Refereed]

     View Summary

    We report on results from Suzaku broadband X-ray observations of the Galactic supernova remnant (SNR) RX J1713.7-3946 with an energy coverage of 0.4-40 keV. With a sensitive hard X-ray measurement from the HXD PIN on board Suzaku, we determine the hard X-ray spectrum in the 12-40 keV range to be described by a power law with photon index Γ = 3.2 ± 0.2, significantly steeper than the soft X-ray index of Γ = 2.4 ± 0.05 measured previously with ASCA and other missions. We find that a simple power law fails to describe the full spectral range of 0.4-40 keV and instead a cutoff power law with hard index Γ = 1.96 ± 0.05 and high energy cutoff εc = 9 ± 1 keV provides an excellent fit over the full bandpass.

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  • Wide Range Multifrequency Observations of Northern TeV Blazars

    Rugamer

    Astronomische Nachrichten   328   623  2007

  • The X-ray observatory Suzaku

    Kazuhisa Mitsuda, Mark Bautz, Hajime Inoue, Richard L. Kelley, Katsuji Koyama, Hideyo Kunieda, Kazuo Makshima, Yoshiaki Ogawara, Robert Petre, Tadayuki Takahashi, Hiroshi Tsunemi, Nicholas E. White, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Hisamitsu Awaki, Aya Bamba, Kevin Boyce, Gregory V. Brown, Kai-Wing Chan, Jean Cottam, Tadayasu Dotanli, John Doty, Ken Ebisawa, Yuichiro Ezoe, Andrew C. Fabian, Enectali Figueroa, Ryuichi Fujimoto, Yasushi Fukazawa, Tae Furusho, Akihiro Furuzawa, Keith Gendreau, Richard E. Griffiths, Yoshito Haba, Kenji Hamaguchi, Ilana Harrus, Gunther Hasinger, Isamu Hatsukade, Kiyoshi Hayashida, Patrick J. Henry, Junko S. Hiraga, Stephen S. Holt, Ann Hornschemeier, John P. Hughes, Una Hwang, Manabu Ishida, Yoshitaka Ishisaki, Naoki Isobe, Masayuki Itoh, Naoko Iyomoto, Steven M. Kahn, Tuneyoshi Kamae, Hideaki Katagiri, Jun Kataoka, Haruyoshi Katayama, Nobuyuki Kawai, Caroline Kilbourne, Kenzo Kinugasa, Steve Kissel, Shunji Kitamoto, Mitsuhiro Kohama, Takayoshi Kohmura, Motohide Kokubun, Taro Kotani, Jun'ichi Kotoku, Aya Kubota, Greg M. Madejski, Yoshitomo Maeda, Fumiyoshi Makino, Alex Markowitz, Chiho Matsumoto, Hironori Matsumoto, Masaru Matsuoka, Kyoko Matsushita, Dan McCammon, Tatehiko Mihara, Kazutami Misaki, Emi Miyata, Tsunefumi Mizuno, Koji Mori, Hideyuki Mori, Mikio Morii, Harvey Moseley, Koji Mukai, Hiroshi Murakami, Toshio Murakami, Richard Mushotzky, Fumiaki Nagase, Masaaki Namiki, Hitoshi Negoro, Kazubiro Nakazawa, John A. Nousek, Takashi Okajima, Yasushi Ogasaka, Takaya Ohashi, Tai Oshima, Naomi Ota, Masanobu Ozaki, Hideki Ozawa, Arvind N. Parmar, William D. Pence, F. Scott Porter, James N. Reeves, George R. Ricker, Ikuya Sakurai, Wilton T. Sanders, Atsushi Senda, Peter Serlemitsos, Ryo Shibata, Yang Soong, Randall Smith, Motoko Suzuki, Andrew E. Szymkowiak, Hiromitsu Takahashi, Torn Tamagawa, Keisuke Tamura, Takayuki Tamura, Yasuo Tanaka, Makoto Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Hiroshi Tomida, Ken'ichi Torii, Yohko Tsuboi, Masahiro Tsujimoto, Takeshi Go Tsuru, Martin J. L. Turner, Yoshihiro Ueda, Shiro Ueno, Masaru Ueno, Shin'ichiro Uno, Yuji Urata, Shin Watanabe, Norimasa Yamamoto, Kazutaka Yamaoka, Noriko Y. Yamasaki, Koujun Yamashita, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Daisuke Yonetoku, Atsumasa Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S1 - S7  2007.01  [Refereed]

     View Summary

    High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

    DOI

  • Suzaku observations of HESS J1616-508: Evidence for a dark particle accelerator

    Hironori Matsumoto, Masaru Ueno, Aya Bamba, Yoshiaki Hyodo, Hideyuki Mori, Hideki Uchiyama, Takeshi Go Tsuru, Katsuji Koyama, Jun Kataoka, Hideaki Katagiri, Tadayuki Takahashi, Junko Hiraga, Shigeo Yamauchi, John P. Hughes, Atsushi Senda, Motohide Kokubun, Takayoshi Kohmura, Frederick S. Porter

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S199 - S208  2007.01  [Refereed]

     View Summary

    We observed the bright unidentified TeV gamma-ray source HESS J1616-508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of 3.1 x 10(-13) erg s(-1) cm(-2) in the 2-10 keV band, which is some 60-times below the gamma-ray flux in the 1-10 TeV band. This object is bright in TeV gamma-rays, but very dim in the X-ray band, and thus is one of the best examples in the Galaxy of a "dark particle accelerator." We also detected soft thermal emission with kT similar to 0.3-0.6 keV near the location of HESS J1616-508. This may be due to a dust-grain scattering halo from the nearby bright supernova remnant RCW 103.

    DOI

  • Iron and nickel line diagnostics for the Galactic Center diffuse emission

    Katsuji Koyama, Yoshiaki Hyodo, Tatsuya Inui, Hiroshi Nakajima, Hironori Matsumoto, Takeshi Go Tsuru, Tadayuki Takahashi, Yoshitomo Maeda, Noriko Y. Yamazaki, Hiroshi Murakami, Shigeo Yamauchi, Yohko Tsuboi, Atsushi Senda, Jun Kataoka, Hiromitsu Takahashi, Stephen S. Holt, Gregory V. Brown

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 1 SPEC. ISS. ) S245 - S255  2007.01  [Refereed]

     View Summary

    We have observed the diffuse X-ray emission from the Galactic Center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provided excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are Fe I K alpha at 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (Fe XXV K alpha) and hydrogenic (Fe XXVI Ly alpha) ions of iron. In addition, K alpha lines from neutral or low ionization nickel (Ni I K alpha) and He-like nickel (Ni XXVII K alpha), Fe I K beta, Fe XXV K beta, Fe XXVI Ly beta, Fe XXV K gamma, and Fe XXVI Ly gamma were detected for the first time. The line center energies and widths of Fe XXV K alpha and Fe XXVI Ly alpha favor a collisional excitation plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of Fe XXV K alpha/Fe XXV K beta is similar to the ionization temperature determined from that of Fe XXV K alpha/Fe XXVI Ly alpha. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic, in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar abundance.

    DOI

  • Hard X-ray Detector (HXD) on board Suzaku

    Tadayuki Takahashi, Keiichi Abe, Manabu Endo, Yasuhiko Endo, Yuuichiro Ezoe, Yasushi Fukazawa, Masahito Hamaya, Shinya Hirakuri, Soojing Hong, Michihiro Horii, Hokuto Inoue, Naoki Isobe, Takeshi Itoh, Naoko Iyomoto, Tuneyoshi Kamae, Daisuke Kasama, Jun Kataoka, Hiroshi Kato, Madoka Kawaharada, Naomi Kawano, Kengo Kawashima, Satoshi Kawasoe, Tetsuichi Kishishita, Takao Kitaguch, Yoshihito Kobayashi, Motohide Kokubun, Jun'ichi Kotoku, Manabu Kouda, Aya Kubota, Yoshikatsu Kuroda, Greg Madejski, Kazuo Makishima, Kazunori Masukama, Yukari Matsumoto, Takefumi Mitani, Ryohei Miyawaki, Tsunefumi Mizuno, Kunishiro Mori, Masanori Mori, Mio Murashima, Toshio Murakami, Kazuhiro Nakazawa, Hisako Niko, Masaharu Nomachi, Yuu Okada, Masanori Ohno, Kousuke Oonuki, Naomi Ota, Hideki Ozawa, Goro Sato, Shingo Shinoda, Masahiko Sugiho, Masaya Suzuki, Koji Taguchi, Hiromitsu Takahashi, Isao Takahashi, Shin'ichiro Takeda, Ken-ichi Tamura, Takayuki Tamura, Takaaki Tanaka, Chiharu Tanihata, Makoto Tashiro, Yukikatsu Terada, Shin'ya Tominaga, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Takayuki Yanagida, Daisuke Yonetoku

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 1 SPEC. ISS. ) S35 - S51  2007.01  [Refereed]

     View Summary

    The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by the combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of a well-type active shield counter. With an effective area of 142 cm(2) at 20 keV and 273 cm(2) at 150 keV, the background level at sea level reached similar to 1 X 10(-5) cts s(-1) cm(-2) keV(-1) at 30 keV for the PIN diodes, and similar to 2 X 10(-5) cts s(-1) cm(-2) keV(-1) at 100 keV, and similar to 7 X 10(-6) cts s(-1) cm(-2) keV(-1) at 200 keV for the phoswich counter. Tight active shielding of the HXD results in a large array of guard counters surrounding the main detector parts. These anti-coincidence counters, made of similar to 4 cm thick BGO crystals, have a large effective area for sub-MeV to MeV gamma-rays. They work as an excellent gamma-ray burst monitor with limited angular resolution (similar to 5 degrees). The on-board signal-processing system and the data transmitted to the ground are also described.

    DOI

  • A Suzaku observation of the low-ionization Fe-Line emission from RCW 86

    Masaru Ueno, Rie Sato, Jun Kataoka, Aya Bamba, Ilana Harrus, Junko Hiraga, John P. Hughes, Caroline A. Kilbourne, Katsuji Koyama, Motohide Kokubun, Hiroshi Nakajima, Masanobu Ozaki, Robert Petre, Tadayuki Takahashi, Takaaki Tanaka, Hiroshi Tomida, Hiroya Yaniaguchi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S171 - S176  2007.01  [Refereed]

     View Summary

    The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant RCW 86 in 2006 February to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock, and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line, which we interpret as K beta emission from low-ionization iron. The Fe K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with n(e)t less than or similar to 10(9) cm(-3) s and kT(e) similar to 5 keV. This combination of low n(e)t and high kT(e) suggests collisionless electron heating in an SNR shock. The Fe K alpha line shows evidence for intrinsic broadening, with a width of 47 (34-59) eV (99% error region). The difference in the spatial distributions of the hard continuum above 3 keV and the Fe K line emission supports a synchrotron origin for the hard continuum.

    DOI

  • Pre-flight performance and radiation hardness of the Tokyo Tech pico-satellite Cute-1.7

    J. Kotoku, J. Kataoka, Y. Kuramoto, Y. Tsubuku, Y. Yatsu, R. Sato, T. Ikagawa, T. Saito, N. Kawai, K. Konoue, N. Miyashita, M. Iai, K. Omagari, M. Kashiwa, H. Yabe, K. Imai, Miyamoto, K. Fujiwara, S. Masumoto, T. Usuda, T. Iljic, A. Konda, S. Sugita, T. Yamanaka, D. Matsuura, T. Sagami, S. Kajiwara, Y. Funaki, S. Matsunaga, T. Shima, S. Kishimoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   565 ( 2 ) 677 - 685  2006.09  [Refereed]

     View Summary

    The Cute-1.7 was launched successfully in February 2006 as a piggyback satellite of the Astro-F mission. The Cute-1.7 dimensions are 10 x 10 x 20 cm(3) box with a total mass of 3.6kg. It is the second pico-satellite to have been developed completely by students of the Tokyo Institute of Technology (Tokyo Tech.) after the successful launch of the CUTE-I in June 2003. The goals of the Cute-1.7 mission are two-fold: (1) to validate high-performance, commercially available products for the first time in space. We particularly use personal digital assistants (PDAs) as a main computer in orbit (2) to demonstrate new potential uses for small satellites in various space studies, as proposed by the "satellite-core" concept. For the Cute-1.7 mission, we will carry avalanche photo diodes (APDs) as a high-count particle monitor in low-Earth orbit. Here we present details of various ground tests and pre-flight performance of the Cute-1.7 immediately before the launch. Results of the Cute-1.7 mission will provide quick feedback for space applications of APDs in Japan's future X-ray astronomy mission NeXT. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

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  • Study of avalanche photodiodes for soft X-ray detection below 20 keV

    Y. Yatsu, Y. Kuramoto, J. Kataoka, J. Kotoku, T. Saito, T. Ikagawa, R. Sato, N. Kawai, S. Kishimoto, K. Mori, T. Kamae, Y. Ishikawa, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   564 ( 1 ) 134 - 143  2006.08  [Refereed]

     View Summary

    The performance of the large area reach-through avalanche photodiode (APD), manufactured by Hamamatsu Photonics, K.K. as a high resolution X-ray detector is presented. The mentioned APD has an area of 3 mm 0, a fast time response for signal carrier collection and its thick depletion layer of 130 pm shows a potential to be used as an effective X-ray absorber below 20 keV. Having a capacitance of similar to 10 pF and a low dark current of 5 nA for a gain of 15, at room temperature, this APD had demonstrated one of the best energy resolutions within this kind of devices: 6.4% (FWHM) for 5.9 keV photons with a minimum detectable energy of 0.3 keV, measured at -20 degrees C. The experiments for the timing property were made in a synchrotron beam facility using an 8 keV X-ray beam; the reached count rate was above 108 counts/s, corresponding to a very short dead time of 4.5 ns/pulse. In order to test the radiation hardness of the APD, the device was irradiated at a Ring Cyclotron Facility with a 53.5 MeV proton beam. The total dose was of 11.3 krad and no fatal damage was found in the APD, although the dark current of the APD had shown an increase of one order of magnitude. Finally, the obtained results allow us to affirm that the reach-through APD has the potential to become an excellent X-ray detector, especially in the space mission application. (c) 2006 Elsevier B.V. All rights reserved.

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  • Dynamics and high-energy emission of the flaring HST-1 knot in the M 87 jet

    L. Stawarz, F. Aharonian, J. Kataoka, M. Ostrowski, A. Siemiginowska, M. Sikora

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   370 ( 2 ) 981 - 992  2006.08  [Refereed]

     View Summary

    Stimulated by recent observations of a giant radio-to-X-ray synchrotron flare from Hubble Space Telescope (HST)-1, the innermost knot of the M 87 jet, as well as by the detection of a very high energy gamma-ray emission from M 87, we investigated the dynamics and multiwavelength emission of the HST-1 region. We study thermal pressure of the hot interstellar medium in M 87 and argue for the presence of a gaseous condensation in its central parts. We postulate that this additional feature is linked to the observed central stellar cusp of the elliptical host. Interaction of the jet with such a feature is likely to result in the formation of a stationary converging/diverging reconfinement/reflected shock structure in the innermost parts of the M 87 jet. We show that for a realistic set of the outflow parameters, a stationary and a flaring part of the HST-1 knot located similar to 100 pc away from the active centre can be associated with the decelerated portion of the jet matter placed immediately downstream of the point where the reconfinement shock reaches the jet axis. We discuss a possible scenario explaining a broad-band brightening of the HST-1 region related to the variable activity of the central core. In particular, we show that assuming a previous epoch of the high central black hole activity resulting in ejection of excess particles and photons down along the jet, one may first expect a high-energy flare of HST-1 due to inverse-Comptonization of the nuclear radiation, followed after a few years by an increase in the synchrotron continuum of this region. The synchrotron flare itself could be accompanied by a subsequent inverse-Compton brightening due to upscattering of the ambient (mostly starlight) photons. If this is the case, then the recently observed order-of-magnitude increase in the knot luminosity in all spectral bands could be regarded as an unusual echo of the order-of-magnitude outburst that had happened previously (and could be eventually observed some similar to 40 yr ago) in the highly relativistic active core of the M 87 radio galaxy. We show that very high energy gamma-ray fluxes expected in a framework of the proposed scenario are consistent with the observed ones.

    DOI

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    134
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  • An active gain-control system for avalanche photo-diodes under moderate temperature variations

    J. Kataoka, R. Sato, T. Ikagawa, J. Kotoku, Y. Kuramoto, Y. Tsubuku, T. Saito, Y. Yatsu, N. Kawai, Y. Ishikawa, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   564 ( 1 ) 300 - 307  2006.08  [Refereed]

     View Summary

    Avalanche photodiodes (APDs) are a promising light sensor for various fields of experimental physics. It has been argued, however, that variation of APD gain with temperature could be a serious problem preventing APDs from replacing traditional photomultiplier tubes (PMTs) in some applications. Here we develop an active gain-control system to keep the APD gain stable under moderate temperature variations. As a performance demonstration of the proposed system, we have tested the response of a scintillation photon detector consisting of a 5 x 5 mm 2 reverse-type APD optically coupled with a CsI(Tl) crystal. We show that the APD gain was successfully controlled under a temperature variation of Delta T = 20 degrees C, within a time-cycle of 6000 s. The best FWHM energy resolution of 6.1 +/- 0.2 % was obtained for 662 keV gamma-rays, and the energy threshold was as low as 6.5 keV, by integrating data from +20 degrees C-0 degrees C cycles. The corresponding values for -20 degrees C-0 degrees C cycles were 6.9 +/- 0.2% and 5.2 keV, respectively. These results are comparable, or only slightly worse than that obtained at a fixed temperature. Our results suggest new potential uses for APDs in various space researches and nuclear physics. As examples, we briefly introduce the NeXT and Cute-1.7 satellite missions that will carry the APDs as scientific instruments for the first time. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

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  • The spectral energy distribution of PKS 2004-447: a compact steep-spectrum source and possible radio-loud narrow-line Seyfert 1 galaxy

    L. C. Gallo, P. G. Edwards, E. Ferrero, J. Kataoka, D. R. Lewis, S. P. Ellingsen, Z. Misanovic, W. F. Welsh, M. Whiting, Th. Boller, W. Brinkmann, J. Greenhill, A. Oshlack

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   370 ( 1 ) 245 - 254  2006.07  [Refereed]

     View Summary

    An investigation of the spectral energy distribution ( SED) of the compact steep-spectrum (CSS) source and possible radio-loud narrow-line Seyfert 1 galaxy (NLS1), PKS 2004-447, is presented. Five out of six well-studied radio-loud NLS1 share this dual classification [optically defined as an NLS1 with radio definition of a CSS or gigahertz-peaked spectrum (GPS) source], suggesting that the connection could have a physical origin. The SED is created from simultaneous observations (within 24 h) at radio (from Australia Telescope Compact Array), optical/near-infrared (NIR) (from Siding Spring) and UV/X-ray (from XMM-Newton) wave-lengths. The X-ray data show evidence of short-term variability (primarily a similar to 30 per cent increase in the final 4 ks of the observation), a possible soft excess and negligible absorption. Together with the rest of the SED, the X-ray emission is excessive in comparison to synchrotron plus synchrotron self-Compton (SSC) models. The SED can be described with a two-component model consisting of extended synchrotron/SSC emission with Comptonization in the X-rays, though SSC models with a very high electron-to-magnetic energy density ratio cannot be excluded either. The peak emission in the SED appears to be in the NIR, which can be attributed to thermal emission (T approximate to 1000 K) from a dusty torus. Analysis of a. non-contemporaneous, low-resolution optical spectrum suggests that the narrow-line region (NLR) is much more reddened than the X-ray emitting region suggesting that the gas-to-dust ratio in PKS 2004-447 may be very different than in our own Galaxy. This could be achieved if the radio jets in PKS 2004-447 deposits material from the nucleus into the NLR. Long-term radio monitoring of PKS 2004-447 shows a rather constant light curve over nearly a six-month period with the exception of one outburst when the 6.65-GHz flux increased by similar to 35 per cent over 19 d. It is not possible to differentiate between intrinsic or extrinsic (i.e. interstellar scintillation) origins for this outburst, but the detection of the rare event demonstrates the importance of intensive monitoring campaigns. In comparison to general samples of GPS sources, which appear to be X-ray weak, NLS1-CSS/GPS sources possess stronger X-ray emission relative to radio ( comparable to normal radio-loud AGN). In addition, NLS1-CSS/GPS sources also exhibit lower intrinsic absorption than GPS sources of similar X-ray luminosity. This is consistent with the additional X-ray component required for PKS 2004-447, but larger samples of NLS1-CSS/GPS are needed before any conclusive remarks can be made.

    DOI

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    64
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  • The X-ray jet in Centaurus A: Clues to the jet structure and particle acceleration

    J Kataoka, L Stawarz, F Aharonian, F Takahara, M Ostrowski, PG Edwards

    ASTROPHYSICAL JOURNAL   641 ( 1 ) 158 - 168  2006.04  [Refereed]

     View Summary

    We report detailed studies of the X-ray emission from the kiloparsec-scale jet in the nearest active galaxy, Centaurus A. By analyzing the highest quality X-ray data obtained with the Chandra ACIS-S, 41 compact sources (mostly bright jet knots) were found within the jet on angular scales less than 400, 13 of which were newly identified. We construct the luminosity function for the detected jet knots and argue that the remaining emission is most likely to be truly diffuse, rather than resulting from the sum of many unresolved fainter knots. We subtracted the contributions of the bright knots from the total X-ray jet flux, and show that the remaining extended emission has a relatively flat-topped intensity profile in the transverse jet direction, with the intensity peaking at the jet boundaries between 5000 and 17000. We note that limb-brightened morphologies have been observed previously at radio frequencies in a few FR I and FR II jet sources, but never so clearly at higher photon energies. Our result therefore supports a stratified jet model, consisting of a relativistic outflow including a boundary layer with a velocity shear. In addition, we found that the X-ray spectrum of the diffuse component is almost uniform across and along the jet, with an X-ray energy spectral index of alpha(X)approximate to 1, similar to those observed in the compact knots. We discuss this spectral behavior within a framework of shock and stochastic particle acceleration processes, connected with the turbulent, supersonic, and nonsteady nature of the relativistic outflow. We note some evidence for a possible spectral hardening at the outer sheath of the jet, and manifesting itself in observed X-ray spectra of alpha(X)&lt; 0.5 in the most extreme cases. Due to the limited photon statistics of the present data, further deep observations of Centaurus A are required to determine the reality of this finding; however, we note that the existence of the hard X-ray features at outer jet boundaries would provide an important challenge to theories for the evolution of ultrarelativistic particles within extragalactic jets.

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    46
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  • The parsec-scale jet of PKS 0637-752

    Philip G. Edwards, B. Glenn Piner, Steven J. Tingay, James E. J. Lovell, Jun Kataoka, Roopesh Ojha, Yasuhiro Murata

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   58 ( 2 ) 233 - 241  2006.04  [Refereed]

     View Summary

    Chandra observations of the quasar PKS 0637-752 during its checkout phase resulted in the unexpected detection of a luminous kiloparsec-scale X-ray jet. The apparent superluminal speed of this jet on the parsec-scale, based on two VSOP and four ground-based observations, has proven crucial to understanding the X-ray production in the arcsec-scale jet. We present here for the first time the full details of the ground-based observations used to determine the parsec-scale jet speed, describe the results of a third VSOP observation, and examine the reported jet speed in the light of more recent ground-based VLBI observations. We find some evidence of increased source activity coincident with extrapolated epochs of jet component ejection, although the monitoring of the source is relatively sparse and the ejection epochs are not tightly constrained. We also construct the spectral energy distribution for the nucleus of PKS 0637-752 and show that it can be modelled well in terms of a one-zone synchrotron self-Compton model of an electron-positron jet with a Doppler factor of similar to 10, consistent with the results of the VLBI observations.

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    9
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  • Kiloparsec-scale jets in FR I radio galaxies and the gamma-ray background

    L Stawarz, TM Kneiske, J Kataoka

    ASTROPHYSICAL JOURNAL   637 ( 2 ) 693 - 698  2006.02  [Refereed]

     View Summary

    We discuss the contribution of kiloparsec- scale jets in FR I radio galaxies to the diffuse gamma- ray background radiation. The analyzed gamma- ray emission comes from inverse- Compton scattering of starlight photon fields by the ultrarelativistic electrons whose synchrotron radiation is detected from such sources at radio, optical, and X- ray energies. We find that these objects, under the minimum- power hypothesis ( corresponding to a magnetic field of 300 mu G in the brightest knots of these jets), can contribute about one percent to the extragalactic gamma- ray background measured by EGRET. We point out that this result already indicates that the magnetic fields in kiloparsec- scale jets of low- power radio galaxies are not likely to be smaller than 10 mu G on average, as otherwise the extragalactic gamma- ray background would be overproduced.

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  • Hard X-ray Imager for the NeXT Mission

    Kazuhiro Nakazawa, Yasushi Fukazawa, Tuneyoshi Kamae, Jun Kataoka, Motohide Kokubun, Kazuo Makishima, Tsunefumi Mizuno, Toshio Murakami, Masaharu Nomachi, Hiroyasu Tajima, Tadayuki Takahashi, Makoto Tashiro, Toru Tamagawa, Yukikatsu Terada, Shin Watanabe, Kazutaka Yamaoka, Daisuke Yonetoku

    SPACE TELESCOPES AND INSTRUMENTATION II: ULTRAVIOLET TO GAMMA RAY, PTS 1 AND 2   6266  2006  [Refereed]

     View Summary

    The hard X-ray imager (HXI) is the primary detector of the NeXT mission, proposed to explore high-energy non-thermal phenomena in the universe. Combined with a novel hard X-ray mirror optics, the HXI is designed to provide better than arc-minutes imaging capability with 1 keV level spectroscopy, and more than 30 times higher sensitivity compared with any existing hard X-ray instruments. The base-line design of the HXI is improving to secure high sensitivity. The key is to reduce the detector background as far as possible. Based on the experience of the Suzaku satellite launched in July 2005, the current design has a well-type tight active shield and multi layered, multi material imaging detector made of Si and CdTe. Technology has been under development for a few years so that we have reached the level where a basic detector performance is satisfied. Design tuning to further improve the sensitivity and reliability is on-going.

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    15
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  • Chandra observation of RCW 89 at two epochs

    Y. Yatsu, N. Kawai, J. Kataoka, T. Tamura, W. Brinkmann

    European Space Agency, (Special Publication) ESA SP   1 ( 604 ) 379 - 380  2006

     View Summary

    We presented a Chandra observation of the HII region RCW 89 in Dec 2004. RCW 89 is part of the radio shell supernova remnant MSH 15-52 which contains a 150 ms young pulsar PSR B1509-58. Comparing with the X-ray image taken by Chandra in Aug 2000, we found that each plasma clouds in RCW 89 have moved outward from the SNR center. The velocity of the radial motion is 5800 ± 2300 km s-1. This result agrees with the scenario in which the plasma clouds in RCW 89 are the SN ejecta from the progenitor of the pulsar.

  • Development of the collimator response of gas slit camera of MAXI

    Mikio Morii, Masaru Matsuoka, Shiro Ueno, Hiroshi Tomida, Haruyoshi Katayama, Kazuyoshi Kawasaki, Takao Yokota, Naoyuki Kuramata, Tatehiro Mihara, Mitsuhiro Kohama, Naoki Isobe, Motoki Nakajima, Hiroshi Tsunemi, Emi Miyata, Atsumasa Yoshida, Kazutaka Yamaoka, Yuichiro Tsuchiya, Takehiro Miyakawa, Nobuyuki Kawai, Jun Kataoka, Satoshi Tanaka, Hitoshi Negoro

    Proceedings of SPIE - The International Society for Optical Engineering   6266 II  2006

     View Summary

    Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky scanner, which will be attached on Exposed Facility of Japanese Experiment Module dubbed "Kibo" of International Space Station (ISS). MAXI will be launched by the Space Shuttle or the Japanese H-IIA Transfer Vehicle (HTV) in 2008. MAXI carries two types of X-ray cameras: Solid-state Slit Camera (SSC) for 0.5 - 10 keV and Gas Slit Camera (GSC) for 2-30 keV bands. Both have long narrow fields of view (FOV) made by a slit and orthogonally arranged collimator plates (slats). The FOV will sweep almost the whole sky once every 96 minutes by utilizing the orbital motion of ISS. Then the light curve of an X-ray point source become triangular shape in one transit. In this paper, we present the actual triangular response of the GSC collimator, obtained by our calibration. In fact they are deformed by gaps between the slats, leaning angle of the slats, and the effective width of the slats. We are measuring these sizes by shooting X-ray beams into the detector behind the collimator. We summarize the calibration and present the first compilation of the data to make the GSC collimator response, which will be useful for public users.

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    4
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  • X-ray emission properties of large scale jets, hotspots and lobes in active galactic nuclei

    J Kataoka, L Stawarz

    PROCEEDINGS OF THE X-RAY UNIVERSE 2005, VOLS 1 AND 2   604 ( 604 ) 633 - +  2006  [Refereed]

     View Summary

    We examine a systematic comparison of jet-knots, hotspots and radio lobes recently observed with Chandra and ASCA. The data was compiled at radio (5 GHz) and X-ray frequencies (1 keV) for more than 40 radio galaxies. We examined three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC) and external Compton on CMB photons (EC). For the SYN sources, X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, a simple formulation of calculating the "expected" SSC or EC fluxes under an equipartition hypothesis is presented. We confirmed that the observed X-ray fluxes are close to the expected ones for non-relativistic emitting plasma velocities in the case of radio lobes and majority of hotspots, whereas considerable fraction of jet-knots is too bright at X-rays to be explained in this way. We concluded, if the inverse-Compton model is the case, the X-ray bright jet-knots are most likely far from the minimum-power condition. We however prefer the other possibility, namely that the observed X-ray emission from all of the jet-knots is synchrotron in origin.

  • 超小型衛星Cute1.7+APD 搭載のAPD センサー技術

    片岡 淳

    OplusE 特集 ~宇宙における光学~   10月号 ( vol.28 ) 1037  2006

  • Suzaku observations of iron lines and reflection in AGN

    J. N. Reeves, A. C. Fabian, J. Kataoka, H. Kunieda, A. Markowitz, G. Miniutti, T. Okajima, P. Serlemitsos, T. Takahashi, Y. Terashima, T. Yaqoob

    ASTRONOMISCHE NACHRICHTEN   327 ( 10 ) 1079 - 1086  2006  [Refereed]

     View Summary

    Initial results on the iron K-shell line and reflection component in several AGN observed as part of the Suzaku Guaranteed Time program are reviewed. This paper discusses a small sample of Compton-thin Seyferts observed to date with Suzaku; namely MCG-5-23-16, MCG-6-30-15, NGC4051, NGC3516, NGC2110, 3C120 and NGC2992. The broad iron K alpha emission line appears to be present in all but one of these Seyfert galaxies, while the narrow core of the line from distant matter is ubiquitous in all the observations. The iron line in MCG-6-30-15 shows the most extreme relativistic blurring of all the objects, the red-wing of the line requires the inner accretion disk to extend inwards to within 2.2R(g) of the black hole, in agreement with the XMM-Newton observations. Strong excess emission in the Hard X-ray Detector (HXD) above 10 keV is observed in many of these Seyfert galaxies, consistent with the presence of a reflection component from reprocessing in Compton-thick matter (e.g. the accretion disk). Only one Seyfert galaxy (NGC 2110) shows neither a broad iron line nor a reflection component. The spectral variability of MCG-6-30-15, MCG-5-23-16 and NGC 4051 is also discussed. In all 3 cases, the spectra appear harder when the source is fainter, while there is little variability of the iron line or reflection component with source flux. This agrees with a simple two component spectral model, whereby the variable emission is the primary power-law, while the iron line and reflection component remain relatively constant. (c) 2006 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim.

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  • Development of 2cm-square Hamamatsu avalanche photodiodes for high-resolution X-rays and gamma-rays detection

    R Sato, J Kataoka, Y Kanai, Y Ishikawa, N Kawabata, T Ikagawa, T Saito, Y Kuramoto, N Kawai

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   556 ( 2 ) 535 - 542  2006.01  [Refereed]

     View Summary

    The avalanche photodiodes (APDs) have attracted considerable attention in various field of experimental physics, but their uses are still limited in only a few experiments, possibly due to their small surface areas. Here, we report the development of the large-area (similar to 20 mm square) APDs, for future applications to high-resolution X-rays and gamma-rays detection. We have made two prototypes of reverse-type APDs based on different concepts, one consists of a 2 x 2 array of 10 x 10 mm(2) pixels (APD1) and the other is a monolithic pixel of 19 x 19mm(2) size (APD2) to achieve a large effective area. By comparing the dark current and gain characteristics at room temperature (+20 degrees C) and lightly cooled environment (-20 degrees C), we quantitatively discussed the origin of predominant noise source at different temperatures. As a performance demonstration of newly developed APDs. we made a scintillation gamma-ray detector consisting of a 20 x 20 x 5mm(3) CsI(Tl) crystal and a 2cm-square APD. The best FWHM energy resolution of 8.5 +/- 0.2% were obtained for 662 keV gamma-rays at room temperature. Similarly, the best FWHM energy resolution of 8.5 0.2% were obtained for 122 keV gamma-rays at lightly cooled environment. We showed that the minimum detectable energy for scintillation light was 15 keV at 20 degrees C and less than 5 keV at -20 degrees C. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Beam test of a prototype phoswich detector assembly for the PoGOLite astronomical soft

    Kanai et

    Nuclear Instruments and Method section-A   570   61  2006

  • HETE-2 localization and observations of the gamma-ray burst GRB 020813

    Sato R, Sakamoto T, Kataoka J, Yoshida A, Suzuki M, Kotoku J, Urata Y, Yamamoto Y, Arimoto M, Tamagawa T, Shirasaki Y, Torii K, Matsuoka M, Nakagawa Y, Yamazaki T, Tanaka K, Maetou M, Yamauchi M, Takagishi K, Lamb DQ, Atteia JL, Vanderspek R, Graziani C, Prigozhin G, Villasenor J, Jernigan JG, Crew GB, Hurley K, Ricker GR, Woosley SE, Butler N, Levine A, Doty JP, Donaghy TQ, Fenimore EE, Galassi M, Boer M, Dezalay JP, Olive JF, Braga J, Manchanda R, Pizzichini G, Kawai N

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   57 ( 6 ) 1031 - 1039  2005.12  [Refereed]

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    5
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  • Design and development of Tokyo Tech pico-satellite Cute-1.7

    Jun'ichi Kotoku, Jun Kataoka, Yusuke Kuramoto, Yoichi Yatsu, Tomoko Ikagawa, Takao Saito, Nobuyuki Kawai, Naoki Miyashita, Masafumi Iai, Kuniyuki Omagari, Ken Fujiwara, Yusuke Funaki, Hideyuki Yabe, Saburo Matunaga, Tatsushi Shima

    Proceedings of SPIE - The International Society for Optical Engineering   5898   1 - 10  2005.12  [Refereed]

     View Summary

    Cute-1.7 is a pico-satellite mainly developed by students at Tokyo Institute of Technology (Tokyo Tech). This will be the second satellite built at Tokyo Tech after the first one, CUTE-I, which was launched in June 2003. The configuration of Cute-1.7 is a 10 cm × 10 cm × 20 cm box with a mass of 2 kg. The engineering objective of Cute-1.7 is to validate commercially available products such as Personal Digital Assistances ( PDAs) in the space environment, and to demonstrate a &quot;satellite core concept&quot; which is dividing a satellite into a bus component and a mission component to adopt various missions. The scientific objective is to demonstrate the performance of avalanche photo diodes (APDs) as future X-ray detectors used in the space environment. Results of this mission will provide the first feedback for a space application of APD such as Japan&#039;s future X-ray astronomy mission NeXT.

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    6
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  • Design and performance of the soft gamma-ray detector for the NeXT mission

    H Tajima, T Kamae, G Madejski, Mitani, I, K Nakazawa, T Tanaka, T Takahashi, S Watanabe, Y Fukazawa, T Ikagawa, J Kataoka, M Kokubun, K Makishima, Y Terada, M Nomachi, M Tashiro

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   52 ( 6 ) 2749 - 2757  2005.12  [Refereed]

     View Summary

    The soft gamma-ray detector (SGD) onboard the Japanese future high energy astrophysics mission (NeXT) is a Compton telescope with narrow field of view, which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor gamma-ray detector which consists of silicon and cadmium telluride (CdTe) detectors. It can detect photons in a wide energy band (0.05-1 MeV) at a background level of 5 x 10(-7) counts/s/cm(2) /keV; the silicon layers are required to improve the performance at a lower energy band (&lt; 0.3 MeV). Excellent energy resolution is the key feature of the SGD, allowing it to achieve both high angular resolution and good background rejection capability. An additional capability of the SGD, its ability to measure gamma-ray polarization, opens up a new window to study properties of astronomical objects. We will present the development of key technologies to realize the SGD: high quality CdTe, low noise front-end application-specific integrated circuit, and bump bonding technology. Energy resolutions of 1.7 keV (full-width at half-maximum) for CdTe pixel detectors and 1.1 keV for Si strip detectors have been measured. We also present the validation of Monte Carlo simulation used to evaluate the performance of the SGD.

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    25
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  • Chandra observation of the interaction between the hot plasma nebula RCW 89 and the pulsar jet of PSR B1509-58

    Y Yatsu, N Kawai, J Kataoka, T Kotani, K Tamura, W Brinkmann

    ASTROPHYSICAL JOURNAL   631 ( 1 ) 312 - 319  2005.09  [Refereed]

     View Summary

    We present a Chandra observation of the H (II) region RCW 89. The nebula lies 10' north from the central pulsar PSR B1509-58, and it has been suggested that the nebula is irradiated by the pulsar jet. We performed a spectral analysis of the seven brightest emitting regions aligned in a "horseshoe'' shape and found that the temperature of the knots increases along the horseshoe in the clockwise direction, while, in contrast, the ionization parameter net decreases. This strongly supports a picture of energy transfer via the precessing pulsar jet. We examined the energy budget assuming that RCW 89 is powered by the pulsar jet and confirmed that the pulsar rotational energy loss is sufficient to drive the nebula. The rate of energy injection into RCW 89 by the jet was estimated from the synchrotron radiation flux. We obtained a heating timescale of 1400 yr, which is consistent with the pulsar characteristic age of 1700 yr. To explain the temperature gradient, we discuss the cooling process for plasma clouds in RCW 89. We argue that the plasma clouds can be cooled down by the adiabatic expansion within 70 yr and form the temperature gradient reflecting the sequential heating by the precessing pulsar jet. We also determined the velocities of the individual plasma clouds by spectral fitting. The plasma clouds in RCW 89 are moving away at 240-860 km s(-1), which constrains the inclination angle of the pulsar spin axis i &gt; 50 degrees and the expanding velocity of the shell as nu(shell) &gt; 1100 km s(-1).

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  • MITSuME - Multicolor Imaging Telescopes for Survey and Monstrous Explosions

    Kotani T, Kawai N, Yanagisawa K, Watanabe J, Arimoto M, Fukushima H, Hattori T, Inata M, Izumiura H, Kataoka J, Koyano H, Kubota K, Kuroda D, Mori J, Nagayama S, Ohta K, Okada T, Okita K, Sato R, Serino Y, Shimizu Y, Shimokawabe T, Suzuki M, Toda H, Ushiyama T, Yatsu Y, Yoshida A, Yoshida M

    NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-COLLOQUIA ON PHYSICS   28 ( 4-5 ) 755 - 758  2005.07

    DOI

  • X-ray emission properties of large-scale jets, hot spots, and lobes in active galactic nuclei

    J Kataoka, L Stawarz

    ASTROPHYSICAL JOURNAL   622 ( 2 ) 797 - 810  2005.04  [Refereed]

     View Summary

    We examine a systematic comparison of jet knots, hot spots, and radio lobes recently observed with Chandra and ASCA. This report discusses the origin of their X-ray emissions and investigates the dynamics of the jets. The data were compiled at well-sampled radio (5 GHz) and X-ray (1 keV) frequencies for more than 40 radio galaxies. We examine three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC), and external Compton (EC) on cosmic microwave background (CMB) photons. For the SYN sources-mostly jet knots in nearby low-luminosity radio galaxies-X-ray photons are produced by ultrarelativistic electrons with energies 10 100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the "expected'' X-ray fluxes under an equipartition hypothesis is presented. We confirm that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and the majority of hot spots, whereas a considerable fraction of jet knots are too bright in X-rays to be explained in this way. We examine two possibilities to account for the discrepancy in a framework of the inverse Compton model: ( 1) the magnetic field is much smaller than the equipartition value, and ( 2) the jets are highly relativistic on kiloparsec and megaparsec scales. We conclude that if the inverse Compton model is the case, the X-ray-bright jet knots are most likely far from the minimum-power condition. We also briefly discuss the other possibility, namely, that the observed X-ray emission from all the jet knots is synchrotron in origin.

    DOI

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  • Recent progress of avalanche photodiodes in high-resoution X-rays and gamma-rays detection

    J Kataoka, T Saito, Y Kuramoto, T Ikagawa, Y Yatsu, J Kotoku, M Arimoto, N Kawai, Y Ishikawa, N Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   541 ( 1-2 ) 398 - 404  2005.04  [Refereed]

     View Summary

    We have studied the performance of large area avalanche photodiodes (APDs) recently developed by Hamamatsu Photonics K.K, in high-resolution X-rays and gamma-rays detections. We show that reach-through APD can be an excellent soft X-ray detector operating at room temperature or moderately cooled environment. We obtain the best energy resolution ever achieved with APDs, 6.4% for 5.9 keV X-rays, and obtain the energy threshold as low as 0.5 keV measured at -20 degrees C. Thanks to its fast timing response, signal carriers in the APD device are collected within a short time interval of 1.9 ns (FWHM). This type of APDs can therefore be used as a low-energy, high-counting particle monitor onboard the forthcoming Pico-satellite Cute1.7. As a scintillation photon detector, reverse-type APDs have a good advantage of reducing the dark noise significantly. The best FWHM energy resolutions of 9.4 +/- 0.3% and 4.9 +/- 0.2% were obtained for 59.5 and 662 keV gamma-rays, respectively, as measured with a CsI(T1) crystal. Combination of APDs with various other scintillators (BGO, GSO, and YAP) also showed better results than that obtained with a photomultiplier tube (PMT). These results suggest that APD could be a promising device for replacing traditional PMT usage in some applications. In particular 2-dim, APD array, which we present in this paper, will be a promising device for a wide-band X-ray and x-ray imaging detector in future space research and nuclear medicine. (c) 2005 Elsevier B.V. All rights reserved.

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    72
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  • Application of CdTe for the NeXT mission

    T Takahashi, K Nakazawa, S Watanabe, G Sato, T Mitani, T Tanaka, K Oonuki, K Tamura, H Tajima, T Kamae, G Madejski, M Nomachi, Y Fukazawa, K Makishima, M Kokubun, Y Terada, J Kataoka, M Tashiro

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   541 ( 1-2 ) 332 - 341  2005.04  [Refereed]

     View Summary

    Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and gamma-ray detection. The high-atomic number of the materials (Z(Cd) = 48, Z(Te) = 52) gives a high quantum efficiency in comparison with Si. The large band-gap energy (E-g = 1.5 eV) allows to operate the detector at room temperature. Based on recent achievements in high-resolution CdTe detectors, in the technology of ASICs and in bump-bonding, we have proposed the novel hard X-ray and gamma-ray detectors for the NeXT mission in Japan. The high-energy response of the super mirror onboard NeXT will enable us to perform the first sensitive imaging observations up to 80keV. The focal plane detector, which combines a fully depleted X-ray CCD and a pixellated CdTe detector, will provide spectra and images in the wide energy range from 0.5 to 80keV. In the soft gamma-ray band up to similar to 1 MeV, a narrow field-of-view Compton gamma-ray telescope utilizing several tens of layers of thin Si or CdTe detector will provide precise spectra with much higher sensitivity than present instruments. The continuum sensitivity will reach several x 10(-8) photons(-1) keV(-1) cm(-1) in the hard X-ray region and a few X 10(-7) photons(-1) keV(-1) cm(-2) in the soft gamma-ray region. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Study of large area Hamamatsu avalanche photodiode in a gamma-ray scintillation detector

    T Ikagawa, J Kataoka, Y Yatsu, T Saita, Y Kuramoto, N Kawai, M Kokubun, T Kamae, Y Ishikawa, N Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   538 ( 1-3 ) 640 - 650  2005.02  [Refereed]

     View Summary

    We have carried out study of a large area (10 x 10 mm(2)), reverse-type avalanche photodiode (APD) recently developed by Hamamatsu photonics. It has low dark current of 3 nA at room temperature, and the gain stability was almost the same as prototypical APDs reported in our previous paper. We studied the performance as a gamma-ray detector with four scintillators, CsI(Tl), BGO, GSO(Ce), and YAP(Ce) crystals. For example we obtained the best energy resolution of 4.9 +/- 0.2 % (FWHM) for 662 keV gamma-rays, as measured with a 10 x 10 x 10 mm 3 CsI(Tl) crystal. The minimum detectable energy was as low as 10 keV at 20degreesC and 3.1 keV at -20degreesC. Thanks to its large effective area, this APD can effectively read out photons from larger size scintillators. When coupling to a 300 x 48 mm(2) BGO plate of 3 mm thickness, an FWHM energy resolution of 20.9 +/- 0.2% was obtained for 662 keV gamma-rays, with the minimum detectable energy of about 60 keV at -15degreesC. These results suggest that our prototype APD can be a promising device for various applications replacing traditional PMTs such as use in space for Japan's future X-ray astronomy mission NeXT. (C) 2004 Elsevier B.V. All rights reserved.

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  • 大学小型衛星Cute-1.7の開発現状(1)

    古徳 純一, 倉本 祐輔, 片岡 淳

    宇宙科学シンポジウム   5   384 - 387  2005.01

    CiNii

  • 24pXK-8 学生主導の小型衛星開発 : 大学小型衛星Cuteの開発現状(X線衛星装置開発,宇宙線・宇宙物理)

    古徳 純一, 片岡 淳, 河合 誠之, 倉本 祐介, 谷津 陽一, 五十川 知子, 齊藤 孝男

    日本物理学会講演概要集   60.1.1   90  2005

    DOI CiNii

  • BGO readout with photodiodes as a soft gamma-ray detector at -30 °C

    T. Nakamoto, Y. Fukazawa, T. Ohsugi, T. Kamae, J. Kataoka

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   536 ( 1-2 ) 136 - 145  2005.01

     View Summary

    BGO is expected to be plausible devices for soft gamma-ray detectors, because of a high detection efficiency for soft gamma-rays. Here we report on the good performance of BGO readout with PIN-photodiode or avalanche photodiode as a soft gamma-ray detector. We confirmed that the signal output of BGO becomes comparable to that of GSO when it is readout with photodiodes due to better matching between emission wavelength of BGO and quantum efficiency of photodiode. The energy resolution of 6.2% and 3.4% for 662 and 1836 keV, respectively, gamma-rays at -30 °C is obtained with the combination of the 5 x 5 x 5mm3 cube BGO and the Hamamatsu avalanche photodiode (APD) S8664-55. In this combination, the lowest detectable energy is found to be ∼ l0keV. These performances are better than that obtained with Photomultiplier tube (PMT), and our results increase many possible applications of BGO readout with photodiodes as soft gamma-ray detectors. © 2004 Elsevier B.V. All rights reserved.

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    8
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  • MITSuME - Multicolor imaging telescopes for survey and monstrous explosions

    T. Kotani, N. Kawai, K. Yanagisawa, J. Watanabe, M. Arimoto, H. Fukushima, T. Hattori, M. Inata, H. Izumiura, J. Kataoka, H. Koyano, K. Kubota, D. Kuroda, M. Mori, S. Nagayama, K. Ohta, T. Okada, K. Okita, R. Sato, Y. Serino, Y. Shimizu, T. Shimokawabe, M. Suzuki, H. Toda, T. Ushiyama, Y. Yatsu, A. Yoshida, M. Yoshida

    Nuovo Cimento della Societa Italiana di Fisica C   28 ( 4-5 ) 755 - 758  2005

     View Summary

    Development of MITSuME is reported. Two 50- cm optical telescopes have been built at Akeno in Yamanashi prefecture and at Okayama Astrophysical Observatory (OAO) in Okayama prefecture. Three CCD cameras for simultaneous g′RcIc photometry are to be mounted on each focal plane, covering a wide FOV of about 30″ × 30″. The limiting magnitude at V is fainter than 18. In addition to these two optical telescopes, a 91-cm IR telescope with a 1° × 1° field of view is being built at OAO, which performs photometry in Y J H K bands. These robotic telescopes can start the observation of counterparts of a GRB within a minute from an alert. We aim to obtain photometric redshifts exceeding 10 with these telescopes. The performance and the current construction status of the telescopes are presented. © Società Italiana di Fisica.

  • Detection of nonthermal X-ray structures near the galactic center with Chandra

    Atsushi Senda, Katsuji Koyama, Ken Ebisawa, Jun Kataoka, Yoshiaki Sofue, Bosch-Ramon, Pietsch

    Proceedings of the International Astronomical Union   1 ( S230 ) 24 - 28  2005

     View Summary

    We have discovered a number of nonthermal X-ray features within central 40 pc region of the Galactic center by analysing 600-ksec observations of Chandra archival data. Most of the detected X-ray structures exhibit small-scale knot-like morphologies and their spectra are well reproduced by single hard power-law with photon indices of 1-2. Among them, the most outstanding features are the three X-ray knots which are aligned on a straight line from the potition of Sgr A* to north-northwest direction. The X-ray properties of these knots lead us to suspect that they are X-ray jets ejected from Sgr A* in the recent past. In addition, we have obtained an indication that the summed flux of nonthermal diffuse X-rays within 30 pc of the GC seems to be smoothly connected to the 20-100 keV flux detected with INTEGRAL IBIS/ISGRI. These results suggest that the origin of GC hard X-rays (or High energy Gamma-rays) is not (or partly) from the Galactic nucleus. © 2006 International Astronomical Union.

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  • Detector response of GSC/MAXI and its expected performance in orbit

    Y. Tsuchiya, A. Yoshida, K. Yamaoka, T. Arakuni, T. Miyakawa, M. Matsuoka, S. Ueno, H. Tomida, T. Yokota, K. Kawasaki, N. Kuramata, H. Katayama, M. Morii, T. Mihara, M. Nakajima, N. Isobe, M. Kohama, H. Tsunemi, E. Miyata, N. Kawai, J. Kataoka, H. Negoro

    Proceedings of SPIE - The International Society for Optical Engineering   5898   1 - 10  2005

     View Summary

    Monitor of All-sky X-ray Image(MAXI) is an X-ray all sky monitor, which will be attached to the Japanese Experiment Module (JEM) on the International Space Station (ISS) around the year 2008. MAXI carries two types of scientific instruments. The Gas Slit Camera(GSC) consists of twelve Xe filled one-dimensional position sensitive gas proportional counters sensitive to X-ray in 2-30 keV band. The Solid-state Slit Camera (SSC) is a set of X-ray CCD arrays sensitive to 0.5-10 keV photons. Both detectors are utilized in combination with a slit and orthogonally arranged collimator plates to produce one-dimensional X-ray images along sky great circles. The instruments are now under fabrication and preflight testing. A detector response matrix (DRM) of GSC is also under development phase based on flight model calibration tests for counters and collimators. MAXI's overall performance depends on not only hardware characteristics but on the fact that the field-of-view changes in time even during observations. To study this complicated situation, we are developing a software, DRM builder, and also a simulation software to evaluate "realistic" performance of GSC in ISS orbits.

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  • Unifying X-ray emission properties of large scale jets, hotspots and lobes in AGN

    J Kataoka, L Stawarz

    High Energy Gamma-Ray Astronomy   745   522 - 527  2005  [Refereed]

     View Summary

    We examine a systematic comparison of jet-knots, hotspots and radio lobes recently observed with Chandra and ASCA. This report will discuss the origin of their X-ray emissions and investigate the dynamics of the jets. The data was compiled at well sampled radio (5 GHz) and X-ray frequencies (1keV) for more than 40 radio galaxies. We examined three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC) and external Compton on CMB photons (EC). For the SYN sources - mostly jet-knots in nearby low-luminosity radio galaxies - X-ray photons are produced by ultrarelativistic electrons with energies 10- 100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the '' expected '' X-ray fluxes under an equipartition hypothesis is presented. We confirmed that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and majority of hotspots, whereas considerable fraction of jet-knots is too bright at X-rays to be explained in this way. We examined two possibilities to account for the discrepancy in a framework of the inverse-Compton model: (1) magnetic field is much smaller than the equipartition value, and (2) the jets are highly relativistic on kpc/Mpc scales. We also briefly discuss the other possibility, namely that the observed X-ray emission from all of the jet-knots is synchrotron in origin.

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  • 活動銀河核の大規模ジェット:X線で探る構造とダイナミクス

    片岡 淳

    天文月報   10月号 ( vol.98 ) 680 - 687  2005

    CiNii

  • Near-infrared, optical, and X-ray observations of the anomalous X-ray pulsar 4U 0142+61

    M Morii, N Kawai, J Kataoka, Y Yatsu, N Kobayashi, H Terada

    YOUNG NEUTRON STARS AND SUPERNOVA REMNANTS   35 ( 6 ) 1177 - 1180  2005  [Refereed]

     View Summary

    We present results from the simultaneous observations of an anomalous X-ray pulsar (AXP) 4U 0142 + 61 on Sep. 2003. We used RXTE, Subaru, and UH88 telescopes to cover X-ray, near-infrared (NIR) (JHK'), and optical (BVRI) bands, respectively. We obtained a simultaneous broadband spectrum for the first time among AXPs. We found NIR excess in the spectrum, which may be another component different from the optical one. We also found a R band dip. We discuss the broadband spectrum covering the optical and X-ray bands in the framework of a self absorbed synchrotron emission from the magnetosphere of magnetar. We also discuss about the R band dip feature, which could put a restriction on the emission models of magnetars. (c) 2005 Published by Elsevier Ltd on behalf of COSPAR.

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  • Low energy response of a prototype detector array for the PoGO astronomical hard X-ray polarimeter

    J. Kataoka, M. Kanal, T. Arimoto, T. Ikagawa, M. Saito, N. Ueno, R. Kawai, P. Blandford, T. Chen, G. Kamae, T. Madejski, J. Mizuno, H. Ng, T. Tajima, L. Thurston, A. Barbier, J. Harding, S. Krizmanic, J. Hunter, R. Mitchell, E. Streitmatter, R. Groth, D. Fernholtz, Y. Marlow, T. Saito, S. Takahashi, H. Gunji, Y. Sakurai, V. Fukazawa, P. Anderson, W. Carlson, M. Klamra, M. Pearce, S. Suhonen, F. Larsson, C. I. Ryde, G. Bjornsson, S. Bogaert, Kishimoto

    Proceedings of SPIE - The International Society for Optical Engineering   5898   1 - 11  2005

     View Summary

    The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from astrophysical objects in the 30-200 keV range. It is under development for the first flight anticipated in 2008. PoGO is designed to minimize the background by an improved phoswich configuration, which enables a detection of 10 % polarization in a 100 mCrab source in a 6-8 hour observation. To achieve such high sensitivity, low energy response of the detector is important because the source count rate is generally dominated by the lowest energy photons. We have developed new PMT assemblies specifically designed for PoGO to read-out weak scintillation light of one photoelectron (1 p.e.) level. A beam test of a prototype detector array was conducted at the KEK Photon Factory, Tsukuba in Japan. The experimental data confirm that PoGO can detect polarization of 80-85 % polarized beam down to 30 keV with a modulation factor 0.25 ± 0.05.

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  • Chandra Observation of the Interaction between the Hot Plasma Nebula RCW 89 and the Pulsar Jet of PSR B1509-58

    Yatsu et a

    Advance in Space Research   35   1066  2005

  • BGO readout with photodiodes as a soft gamma-ray detector at -30 deg

    Nakamoto et

    Nuclear Instruments and Method section-A   2005   536 - 136  2005

  • HETE-2 localization and observations of the gamma-ray burst GRB 020813

    Rie Sato, Takanori Sakamoto, Jun Kataoka, Atsumasa Yoshida, Motoko Suzuki, Junichi Kotoku, Yuji Urata, Yoshihisa Yamamoto, Makoto Arimoto, Toru Tamagawa, Yuji Shirasaki, Ken'ichi Torii, Masaru Matsuoka, Yujin Nakagawa, Toru Yamazaki, Kaoru Tanaka, Miki Maetou, Makoto Yamauchi, Kunio Takagishi, Donald Q. Lamb, Jean-Luc Atteia, Roland Vanderspek, Carlo Graziani, Gregory Prigozhin, Joel Villasenor, J. Garrett Jernigan, Geoffrey B. Crew, Kevin Hurley, George R. Ricker, Stanford E. Woosley, Nat Butler, Al Levine, John P. Doty, Timothy Q. Donaghy, Edward E. Fenimore, Mark Galassi, Michel Boer, Jean-Pascal Dezalay, Jean-François Olive, Joao Braga, Ravi Manchanda, Graziella Pizzichini, Nobuyuki Kawai

    Publications of the Astronomical Society of Japan   57 ( 6 ) 1031 - 1039  2005

     View Summary

    A bright, long gamma-ray burst (GRB) was detected and localized by the instruments on board the High Energy Transient Explorer 2 satellite (HETE-2) at 02:44:19.17 UTC (9859.17 s UT) on 2002 August 13. The location was reported to the GRB Coordinates Network (GCN) about 4 min after the burst. In the prompt emission, the burst had a duration of approximately 125 s, and more than four peaks. We analyzed the time-resolved 2-400 keV energy spectra of the prompt emission of GRB 020813 using the Wide Field X-Ray Monitor (WXM) and the French Gamma Telescope (FREGATE) in detail. We found that the early part of the burst (17-52 s after the burst trigger) shows a depletion of low-energy photons below about 50 keV. It is difficult to explain the depletion by either synchrotron self-absorption or Comptonization. One possibility is that the low-energy depletion may be understood as a mixture of "jitter" radiation with the usual synchrotron radiation component. © 2005. Astronomical Society of Japan.

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  • Evolution of the synchrotron spectrum in Markarian 421 during the 1998 campaign

    C Tanihata, J Kataoka, T Takahashi, GM Madejski

    ASTROPHYSICAL JOURNAL   601 ( 2 ) 759 - 770  2004.02  [Refereed]

     View Summary

    The uninterrupted 7 day ASCA observations of the TeV blazar Mrk 421 in 1998 have clearly revealed that X-ray flares occur repeatedly. In this paper, we present the results of the time-resolved spectral analysis of the combined data taken by ASCA, RXTE, BeppoSAX, and the Extreme Ultraviolet Explorer (EUVE). In this object-and in many other TeV blazars-the precise measurement of the shape of the X-ray spectrum, which reflects the high-energy portion of the synchrotron component, is crucial in determining the high-energy cutoff of the accelerated electrons in the jet. Thanks to the simultaneous broadband coverage, we measured the 0.1-25 keV spectrum resolved on timescales as short as several hours, providing a great opportunity to investigate the detailed spectral evolution at the flares. By analyzing the time-subdivided observations, we parameterize the evolution of the synchrotron peak, where the radiation power dominates, by fitting the combined spectra with a quadratic form [where the nuF(nu) flux at the energy E obeys log nuF(nu)( E)=log (nuF(nu), (peak))-const(log E-log E-peak)(2)]. In this case, we show that there is an overall trend that the peak energy E-peak and peak flux nuF(nu,pea)k increase or decrease together. The relation of the two parameters is best described as E-peak proportional to nuF(nu,peak)(0.7) for the 1998 campaign. Similar results were derived for the 1997 observations, while the relation gave a smaller index when both 1997 and 1998 data were included. On the other hand, we show that this relation, and also the detailed spectral variations, differs from flare to flare within the 1998 campaign. We suggest that the observed features are consistent with the idea that flares are due to the appearance of a new spectral component. With the availability of the simultaneous TeV data, we also show that there exists a clear correlation between the synchrotron peak flux and the TeV flux.

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  • Development of large area avalanche photodiode for future space research

    Tomoko Ikagawa, Jun Kataoka, Nobuyuki Kawai

    Progress of Theoretical Physics Supplement   155   345 - 346  2004

     View Summary

    We report on the performance of recent avalanche photodiodes (APDs) produced by Hamamatsu photonics as a new X-ray and γ-ray detector. An FWHM energy resolution of 6.5% was obtained for direct detection of 5.9 keV X-rays, whereas 9.4% was obtained for 59.5 keV γ-rays measured with a CsI crystal. Because of their small volumes and low operating bias voltage, APDs are promising devices for future space research. We are planning to use them for our small satellites, CUTE-1.7 and Hu-ring.

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  • Particle acceleration and energy transport in the relativistic jets

    Jun Kataoka

    Progress of Theoretical Physics Supplement   155   351 - 352  2004

     View Summary

    The vast bulk of cosmic-ray (CR) nuclei and electrons are thought to be accelerated in the shock waves of SNRs. The location of strong shocks and more extended structures than SNRs can potentially accelerate particles above 100 TeV. The Chandra X-ray Observatory has now resolved the X-ray spatial structure along jets, from kpc to Mpc, of more than a dozen of radio galaxies. These observations have established that particles are accelerated efficiently in radio galaxies, up to energies of 10-100 TeV. I present recent progress in the Chandra observation of AGN jets and discuss the energy transport from the vicinity of the central black hole to the kpc scale jets.

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  • The observational response of MAXI onboard ISS

    Naoki Isobe, Masaru Matsuoka, Shiro Ueno, Hiroshi Tomida, Kazuyoshi Kawasaki, Haruyoshi Katayama, Tatehiro Mihara, Mitsuhiro Kohama, Ikuya Sakurai, Motoki Nakajima, Nobuyuki Kawai, Jun Kataoka, Atsumasa Yoshida, Daiki Takahashi, Masami Uzawa, Hiroshi Tsunemi, Emi Miyata, Isao Tanaka

    Proceedings of SPIE - The International Society for Optical Engineering   5165   354 - 365  2004

     View Summary

    The current status is reported of the development of Monitor of All-sky X-ray Image and the measurement of its observational response. MAXI is a scanning X-ray camera to be attached to the Japanese Experiment Module of the International Space Station in 2008. MAXI is mainly composed of two kinds of instruments, GSC which is sensitive to the 2 - 30 keV photons, and SSC to the 0.5 - 10 keV ones. As an X-ray all-sky monitor, MAXI has an unprecedented sensitivity of 7 mCrab in one orbit scan, and 1 mCrab in one week. Using the engineering mode of the proportional counter and of the collimator for GSC, the observational response of GSC is extensively measured. The acceptable performances are obtained as a whole for both the collimator and the counter. The engineering models of the other part of MAXI are also constructed and the measurement of their performance is ongoing.

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  • Hu-ring: A small university satellite for gamma-ray burst

    N. Kawai, H. Okada, N. Miyashita, T. Urabe, M. Kashiwa, T. Tachikawa, N. Yamaguchi, K. Omagari, I. Morita, Y. Yamamoto, Y. Yatsu, T. Ikagawa, J. Kataoka, S. Matunaga

    Proceedings of SPIE - The International Society for Optical Engineering   5488 ( PART 2 ) 967 - 976  2004

     View Summary

    We propose a university-class micro-satellite "Hu-ring" to localize and study gamma-ray bursts. The primary mission of Hu-ring is to localize gamma-ray bursts with an 10́ accuracy in real time, and transmit promptly the coordinates to the ground. Although many of its mission concepts are modeled after HETE-2, use of avalanche photodiodes (APDs), innovative photon detector device, make it possible to further reduce the size and the mass of the satellite. We designed Hu-ring within a size of 50 cm cube and a weight limit of 50 kg, so that it can be launched as a piggy-back payload of the Japanese H-IIA Launch Vehicle. The satellite is spin-stabilized, and has a half-sky field of view centered on the anti-sun direction. A set of scintillation counters equipped with rotation modulation collimators are employed for localization of GRBs. We also measure the soft/medium X-ray spectra of GRBs using APDs as a direct X-ray photon detectors. These two kinds of instruments cover the 0.5-200 keV energy range. The satellite bus is designed mostly with commercially available components in order to reduce the cost and the lead time. Following the HETE-2 model, in order to receive the prompt burst alerts it is designed to rely on a global network of receive-only low-cost ground stations, which may be hosted at research instutions with a small footprint. We performed analyses in many aspects: mechanical and thermal design of the satellite bus, attitude control simulations, power budget, ground contact schedule and downlink capacity, etc. We verified that the mission goal can be achieved with this proposed design philosophy.

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    2
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  • Development status and performance estimation of MAXI

    Shiro Ueno, Hiroshi Tomida, Naoki Isobe, Haruyoshi Katayama, Kazuyoshi Kawasaki, Takao Yokota, Naoyuki Kuramata, Masaru Matsuoka, Tatehiro Mihara, Ikuya Sakurai, Motoki Nakajima, Mitsuhiro Kohama, Hiroshi Tsunemi, Emi Miyata, Nobuyuki Kawai, Jun Kataoka, Yuuri Serino, Yoshihisa Yamamoto, Atsumasa Yoshida, Hitoshi Negor

    Proceedings of SPIE - The International Society for Optical Engineering   5488 ( PART 1 ) 197 - 208  2004

     View Summary

    Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky monitor, which will be delivered to the International Space Station (ISS) in 2008, to scan almost the whole sky once every 96 minutes for a mission life of two years. The detection sensitivity will be 7 mCrab (5σ level) in one scan, and 1 mCrab for one-week accumulation. At previous SPIE meetings, we presented the development status of the MAXI payload, in particular its X-ray detectors. In this paper, we present the whole picture of the MAXI system, including the downlink path and the MAXI ground system. We also examine the MAXI system components other than X-ray detectors from the point of view of the overall performance of the mission. The engineering model test of the MAXI X-ray slit collimator shows that we can achieve the position determination accuracy of <0.1 degrees, required for the ease of follow-up observations. Assessing the downlink paths, we currently estimates that the MAXI ground system receive more than 50% of the observational data in "real time" (with time delay of a few to ten seconds), and the rest of data with delay of 20 minutes to a few hours from detection, depending on the timing of downlink. The data will be processed in easily-utilised formats, and made open to public users through the Internet.

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  • Robotic telescope for rapid gamma-ray burst follow-up observations

    R. Sato, N. Kawai, M. Suzuki, Y. Yatsu, J. Kataoka

    Proceedings of SPIE - The International Society for Optical Engineering   5492 ( PART 2 ) 859 - 870  2004

     View Summary

    We have developed a robotic telescope at Tokyo Institute of Technology (Tokyo Tech) to perform rapid follow-up observations of early optical afterglows of gamma-ray bursts (GRBs). Our system was primarily designed to respond quickly to the GRB locations notified by the High Energy Transient Explorer 2 (HETE-2) satellite, but it can also respond to all the notifications provided by the GRB Coordinates Network (GCN). In order to cover the error circle of the HETE-2, wide-field and thermo-electrically cooled CCD camera is equipped on the focus of a small 30cm telescope. A field of view of our system is 44 arcminutes which can cover the most error circles of the HETE-2. The rapid response (less than 15 sec after the notice) and slew speeds (6 deg / sec) make our system appropriate for observing GRB afterglows. Using this convenient system, we detected the optical afterglow of GRB 030329. Observation was started 67 minutes after the burst, which was one of the earliest detection in the world. We report the performance of our telescope coupled to CCD camera, and estimate the limiting magnitude of our system. Although our system is located in a region affected by strong city lights, the limiting magnitude is approximately 17.3 mag.

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  • Large-area balloon-borne polarized gamma ray observer (PoGO)

    R Blanford, P Chen, T Kamae, G Madejski, J Ng, T Mizuno, H Tajima, T Thurston, L Barbier, P Bloser, T Cline, S Hunter, A Harding, J Krizmanic, J Mitchell, R Streitmatter, J Tueller, E Groth, R Fernholz, D Marlow, G Bogaert, S Gunji, H Sakurai, Y Saito, T Takahashi, J Kataoka, N Kawai, Y Fukazawa, P Carlson, W Klamra, M Pearce, CI Bjornsson, C Fransson, S Larsson, F Ryde

    2003 IEEE NUCLEAR SCIENCE SYMPOSIUM, CONFERENCE RECORD, VOLS 1-5     1708 - 1713  2004  [Refereed]

     View Summary

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (25-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO will detect 10% polarization in 100m Crab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter technology used in balloon-borne experiments (Welcome-1) and AstroE2 Hard X-ray Detector. PoGO consists of close-packed array of 397 hexagonal well-type phoswich counters. Each unit is composed of a long thin tube (well) of slow plastic scintillator, a solid rod of fast plastic scintillator, and a short BGO at the base. A photomultiplier coupled to the end of the BGO detects light from all 3 scintillators.
    The rods with decay times &lt; 10 ns, are used as the active elements; while the wells and BGOs, with decay times similar to 250 ns are used as active anti-coincidence. The fast and slow signals are separated out electronically.
    When gamma rays entering the field-of-view (fwhmsimilar to 3deg(2)) strike a fast scintillator, some are Compton scattered. A fraction of the scattered photons are absorbed in another rod (or undergo a second scatter). A valid evnet requires one clean fast signal of pulse-height compatible with photo-absorption (&gt; 20keV) and one or more compatible with Compton scattering (&lt; 10keV). Studies based on EGS4 (with polarization features) and Geant4 predict excellent background rejection and high sensitivity.

  • The next gamma-ray satellite GLAST for BLAZAR observations

    Fukazawa, Y, Obsugi, T, Yoshida, S, Kamae, T, Mizuno, T, Takahashi, T, Ozaki, M, Kawai, N, Kataoka, J

    PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT   155 ( 155 ) 327 - 328  2004  [Refereed]

     View Summary

    The next gamma-ray satellite GLAST will be launched in 2007, under the cooperation of the USA, Japan, Italy, France, Sweden, and so on. GLAST sensitivity is several tens times higher than the EGRET, thanks to good position determination, large effective area, and wide field of view. The key technology to achieve these capabilities is low-noise silicon-strip-detector&quot; (SSD), developed and designed by Hiroshima University and Hamamatsu Photonics. Most of the GLAST SSD has been produced, and found to be very high-quality devices with quite a low rate of dead channels of &lt; 0.01%. The detector assembly has started, and soon one tower will become built for various environmental tests. GLAST will detect several thousands of BLAZARs, and thus enable us to probe the jet mechanisms and evolution of massive black holes. Good position accuracy will in addition increase an identification. The high-sensitivity, wide-energy-band, and continuous-long-time observations of BLAZARs with GLAST LAT will be hoped to open a new epoch of massive black-hole observations. Especially, the flare history is very important to consider the jet mechanims and particle acceleration.&quot;

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  • Design and performance of soft gamma-ray detector for NeXT mission

    Tajima H, Kamae T, Madejski G, Mitani T, Nakazawa K, Tanaka T, Takahashi T, Watanabe S, Fukazawa Y, Ikagawa T, Kataoka J, Kokubun M, Makishima K, Terada Y, Nomachi M, Tashiro M

    2004 IEEE Nuclear Science Symposium Conference Record, Vols 1-7     314 - 321  2004  [Refereed]

  • Wide band X-ray Imager (WXI) and Soft Gamma-ray Detector (SGD) for the NeXT Mission

    Takahashi T, Awaki A, Dotani T, Fukazawa Y, Hayashida K, Kamae T, Kataoka J, Kawai N, Kitamoto S, Kohmura T, Kokubun M, Koyama K, Makishima K, Matsumoto H, Miyata E, Murakami T, Nakazawa K, Nomachi M, Ozaki M, Tajima H, Tashiro M, Tamagawa T, Terada Y, Tsunemi H, Tsuru T, Yamaoka K, Yonetoku D, Yoshida A

    Proceedings of SPIE - The International Society for Optical Engineering   5488 ( PART 2 ) 549 - 560  2004  [Refereed]

     View Summary

    The NeXT mission has been proposed to study high-energy non-thermal phenomena in the universe. The high-energy response of the super mirror will enable us to perform the first sensitive imaging observations up to 80 keV. The focal plane detector, which combines a fully depleted X-ray CCD and a pixelated CdTe detector, will provide spectra and images in the wide energy range from 0. 5 keV to 80 keV. In the soft gamma-ray band upto ∼ 1 MeV, a narrow field-of-view Compton gamma-ray telescope utilizing several tens of layers of thin Si or CdTe detector will provide precise spectra with much higher sensitivity than present instruments. The continuum sensitivity will reach several x 10-8 photons/s/keV/cm2 in the hard X-ray region and a few × 107 photons/s/keV/cm2 in the soft γ-ray region.

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  • Earliest detection of the optical afterglow of GRB 030329 and its variability

    R Sato, N Kawai, M Suzuki, Y Yatsu, J Kataoka, R Takagi, K Yanagisawa, H Yamaoka

    PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT   599 ( 155 ) 411 - 412  2004  [Refereed]

     View Summary

    We report an earliest detection of an optical afterglow of GRB 030329 at the Tokyo Institute of Technology (Tokyo, Japan). Our observation started 67 minutes after the burst and continued for two succeeding nights. Combining our data with those reported in GCN, we find that the early afterglow light curve of the first half day is described by a broken power-law, (alpha t(-alpha)) function with indices alpha(1) = 0.88 +/- 0.01 (0.047 days &lt; t &lt; t(b1)), alpha(2) = 1.18 +/- 0.01 (t(b1) &lt; t &lt; t(b2)), and alpha(3) = 1.81 +/- 0.04 (t(b2) &lt; t &lt; 1.2 days), where t(b1) similar to 0.26 days and t(b2) similar to 0.54 days, respectively. The change of the power-law index at the first break at t similar to 0.26 days is consistent with that expected from a "cooling break".

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  • Performance of the most recent avalanche photodiodes for future X-ray and gamma-ray astronomy

    J Kataoka, T Ikagawa, Y Yatsu, Y Kuramoto, T Saito, N Kawai, Y Serino, J Kotoku, Y Ishikawa, N Kawabata

    HIGH-ENERGY DETECTORS IN ASTRONOMY   5501   249 - 260  2004  [Refereed]

     View Summary

    We report on the performance of the most recent avalanche photodiodes produced by Hamamatsu Photonics, as low-energy X-rays and gamma-rays detectors. APDs share good features of both photo diodes and PMTs, as they are very compact, produce an internal gain of 10-100, and have high quantum efficiency close to 100% in the visible right. Until very recently, however, APDs were limited to very small surfaces, and were mainly used as a digital device for light communication. We have developed large area (up to 10x10 mm(2)) APDs which can be used in the physics experiments. The best energy resolution of 6.4% (FWHM) was obtained in direct detection of 5.9 keV X-rays. The FWHM results of 9.4% and 4.9% were obtained for 59.5 keV and 662 keV gamma-rays respectively, as measured with the CsI(Tl) crystal. The minimum detectable energy for the scintillation light was as low as 1 keV at lightly cooled environment (-20degreesC). Note that our results are the best records ever achieved with APDs. Various applications of APDs are presented for future space research and nuclear medicine. In particular 2-dimensional APD arrays will be a promising device for a wide-band X-ray and gamma-ray imaging detector.

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  • Ground Support Electronics for testing the preflight performance of the MAXI-GSC

    J Kataoka, Y Serino, N Kawai, T Arakuni, A Yoshida, M Uzawa, M Kohama, Sakurai, I, T Mihara, H Negoro, N Isobe, H Katayama, K Kawasaki, N Kuramata, M Matsuoka, H Tomida, S Ueno, T Yokota, E Miyata, M Nomachi, H Tsunemi

    X-RAY AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY XIII   5165   375 - 386  2004  [Refereed]

     View Summary

    MAXI is an X-ray all-sky monitor which will be mounted on the Japanese Experimental Module (JEM) of the International Space Station (ISS) in 2008. The Gas Slit Camera (GSC) consists of 12 one-dimensional position sensitive proportional counters and the sensitivity will be as high as 1 mCrab for a one-week accumulation in the 2-30 keV band. In order to calibrate the detectors and electronic systems thoroughly before the launch, a fast and versatile Ground Support Electronic (GSE) system is necessary. We have developed a new GSE based on VME I/O boards for a Linux workstation. These boards carry reconfigurable FPGAs of 100,000 gates, together with 16 Mbytes of SDRAM. As a demonstration application of using this GSE, we have tested the positional response of a GSC engineering counter. We present a schematic view of the GSE highlighting the functional design, together with a future vision of the ground testing of the GSC flight counters and digital associated processor.

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  • Performance of large-area avalanche photodiode for low-energy X-rays and gamma-rays scintillation detection

    Ikagawa, T, Kataoka, J, Yatsu, Y, Kawai, N, Mori, K, Kamae, T, Tajima, H, Mizuno, T, Fukazawa, Y, Ishikawa, Y

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   515 ( 3 ) 671 - 679  2003.12  [Refereed]

     View Summary

    We report on the performance of large-area (5 x 5 mm(2)) avalanche photodiodes (APD) produced by Hamamatsu Photonics, as a low-energy X-rays and gamma-rays scintillation detector. Hamamatsu APD has a reverse structure and works at relatively low bias voltage of 300-350 V. The leakage current is 1.2 nA at room temperature (25degreesC) and decreases to 10 pA at -20degreesC for an avalanche gain of 50. The best FWHM energy resolutions of 9.4+/-0.3% and 7.4+/-0.3% were obtained for 59.5 keV gamma-rays from Am-241 and 122 keV gamma-rays from Co-57 sources, respectively, as measured with a 5 x 5 x 5mm(3) cubic CsI(TI) crystal. We show that the minimum detectable energy for the scintillation light is remarkably low; 4.6 keV at room temperature (20degreesC) and 1.1 keV at -20degreesC. 5.9 keV X-rays from Fe-55 were clearly resolved at -20degreesC with an FWHM resolution of 32.9+/-0.3%. These results suggest that Hamamatsu APD can be a promising device for future applications in low-energy scintillation detection. (C) 2003 Elsevier B.V. All rights reserved.

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  • Chandra observation of the anomalous X-ray pulsar 1E 1841-045

    M Morii, R Sato, J Kataoka, N Kawai

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   55 ( 3 ) L45 - L48  2003.06  [Refereed]

     View Summary

    We present the results from a Chandra ACIS CC mode observation of an anomalous X-ray pulsar (AXP) 1E 1841-045. This was the first observation in which the pulsar spectrum over a wide energy range was spatially discriminated from the surrounding SNR, Kes 73. Like other AXPs, the phase-integrated spectrum was fitted well with a power-law plus blackbody model. The spectral parameters are Gamma = 2.0 +/- 0.3, kT(BB) = 0.44 +/- 0.02 keV, and N-H = 2.54(-0.13)(+0.15) x 10(22)cm(-2). This photon index is the flattest among AXPs, and resembles soft gamma-ray repeaters (SGRs) in a quiescent state. The pulse profile is double-peaked, and we found that the second peak has a significantly hard spectrum. The spectra of all phases are consistent with a power-law plus blackbody model with a constant temperature and photon index. When fitted with a two-blackbody model, we obtained a similarly good fit. These results can be interpreted by saying that there are two emission regions with different energy spectra.

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  • Implications of variability patterns observed in TeV blazars on the structure of the inner jet

    C Tanihata, T Takahashi, J Kataoka, GM Madejski

    ASTROPHYSICAL JOURNAL   584 ( 1 ) 153 - 163  2003.02  [Refereed]

     View Summary

    The recent long-look X-ray observations of TeV blazars have revealed many important new features concerning their time variability. In this paper we suggest a physical interpretation for those features based on the framework of the internal and external shock scenarios. We present a simplified model applicable to TeV blazars and investigate through simulations how each of the model parameters would affect the observed light curve or spectrum. In particular, we show that the internal shock scenario naturally leads to all the observed variability properties, including the structure function, but for it to be applicable, the fractional fluctuation of the initial bulk Lorentz factors must be small, sigma'(Gamma) = sigma(Gamma)/Gamma(avg) &lt;&lt; 0.01. This implies very low dynamical efficiency of the internal shock scenario. We also suggest that several observational quantities such as the characteristic timescale, the relative amplitude of flares as compared to the steady ("offset") component, and the slope of the structure function can be used to probe the inner jet. The results are applied to the TeV blazar Mrk 421, and this, within the context of the model, leads to the determination of several physical parameters: the ejection of a shell with average thickness of similar to10(13) cm occurs on average every 10 minutes, and the shells collide similar to10(17) cm away from the central source.

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  • Chandra detection of hotspot and knots of 3C 303

    J Kataoka, P Edwards, M Georganopoulos, F Takahara, S Wagner

    ASTRONOMY & ASTROPHYSICS   399 ( 1 ) 91 - 97  2003.02  [Refereed]

     View Summary

    We report the detection at X-rays of the radio/optical hotspot and knots of 3C 303 from a short (15 ksec) Chandra exposure in 2001 March. The X-ray morphology is similar to that of the radio/optical emission with peaks in the X-ray emission found at 5.5" (knot B), 9" (knot C) and 17" (hotspot) from the core of 3C 303. Despite the limited signal-to-noise ratio of the short Chandra exposure, the X-ray photon spectrum was measured for the hotspot. We construct the spectral energy distribution (SED) and find that the X-ray flux is well below the extrapolation of the radio-to-optical continuum, which we interpret as resulting from the production of X-rays via inverse Compton scattering of both synchrotron photons (SSC) and cosmic microwave background photons (EC/CMB). The magnetic field strength, region size, and the maximum energy of electrons are self-consistently determined for the hotspot to be B similar or equal to 4.3 muG, R similar or equal to 6.5 x 10(21) cm, and gamma(max) similar or equal to 1.4 x 10(7). This implies a magnetic field strength a factor of similar to30 below the equipartition value; B-eq 150 muG. The origin of this large departure from equipartition is still uncertain, but the discrepancy is reduced if the plasma in the hotspot is moving with mildly relativistic speeds. Our observation of 3C 303, as well as recent Chandra detections of large scale jets and hotspots in a number of radio galaxies, confirm that particles are accelerated very efficiently in radio galaxies.

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  • Large-area balloon-borne polarized gamma ray observer (PoGO)

    Roger Blanford, Psin Chen, Tuneyoshi Kamae, Grzegorz Madejski, Johnny Ng, Tsunefumi Mizuno, Hiroyasu Tajima, Timothy Thurston, Louis Barbier, Peter Bloser, Thomas Cline, Stanley Hunter, Alice Harding, John Krizmanic, John Mitchell, Robert Streitmatter, Jack Tueller, Edward Groth, Richard Fernholz, Daniel Marlow, Gilles Bogaert, Shuichi Gunji, Hirohisa Sakurai, Yoshitaka Saito, Tadayuki Takahashi, Jun Kataoka, Nobuyuki Kawai, Yasushi Fukazawa, Per Carlson, Wlodzimierz Klamra, Mark Pearce, Claes Ingvar Bjornsson, Claes Fransson, Stefan Larsson, Felix Ryde

    IEEE Nuclear Science Symposium Conference Record   3   1708 - 1713  2003  [Refereed]

     View Summary

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (25-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO will detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter technology used in balloon-borne experiments (Welcome-1) and AstroE2 Hard X-ray Detector. PoGO consists of close-packed array of 397 hexagonal well-type phoswich counters. Each unit is composed of a long thin tube (well) of slow plastic scintillator, a solid rod of fast plastic scintillator, and a short BGO at the base. A photomultiplier coupled to the end of the BGO detects light from all 3 scintillators. The rods with decay times < 10 ns, are used as the active elements; while the wells and BGOs, with decay times ∼ 250 ns are used as active anti-coincidence. The fast and slow signals are separated out electronically. When gamma rays entering the field-of-view (fwhm∼ 3deg 2) strike a fast scintillator, some are Compton scattered. A fraction of the scattered photons are absorbed in another rod (or undergo a second scatter). A valid evnet requires one clean fast signal of pulse-height compatible with photo-absorption (> 20keV) and one or more compatible with Compton scattering (< 10keV). Studies based on EGS4 (with polarization features) and Geant4 predict excellent background rejection and high sensitivity.

  • Performance of Large Area Avalanche Photodiode as a Low Signal Photon Detector

    Ikagawa et

    Nuclear Instruments and Method section-A   515   663 - 663  2003

    CiNii

  • Chandra Discovery of an X-ray Jet and Lobes in 3C15

    J.Kataoka

    Astronomy &amp; Astrophysics   410   833  2003

  • RXTE observations of 3C 273 between 1996 and 2000: variability time-scale and jet power

    J Kataoka, C Tanihata, N Kawai, F Takahara, T Takahashi, PG Edwards, F Makino

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   336 ( 3 ) 932 - 944  2002.11  [Refereed]

     View Summary

    We present the results of a long-look monitoring of 3C 273 with RXTE between 1996 and 2000. A total of 230 observations amounts to a net exposure of 845 ks, with this spectral and variability analysis of 3C 273 covering the longest observation period available at hard X-ray energies. Flux variations by a factor of 4 have been detected over 4 yr, whereas flux variations of less than 30 per cent have been observed for individual flares on time-scales of similar to3 d. Two temporal methods, the power spectrum density (PSD) and the structure function (SF), have been used to study the variability characteristics of 3C 273. The hard X-ray photon spectra generally show a power-law shape with a differential photon index of Gamma similar or equal to 1.6 +/- 0.1. In 10 of 261 data segments, exceptions to power-law behaviour have been found: (i) an additional soft excess below 4 keV; and (ii) a broad Fe fluorescent line feature with EW similar to 100-200 eV. Our new observations of these previously reported X-ray features may imply that 3C 273 is a unique object whose hard X-ray emission occasionally contains a component that is not related to a beamed emission (Seyfert-like), but most hard X-rays are likely to originate in inverse Compton radiation from the relativistic jet (blazar-like). Multifrequency spectra from radio to gamma-rays are presented in addition to our RXTE results. The X-ray time variability and spectral evolution are discussed in the framework of the beamed, synchrotron self-Compton picture. We consider the 'power balance' (both radiative and kinetic) between the accretion disc, the sub-parsec-scale jet and the 10-kpc-scale jet.

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  • Observation of gamma rays greater than 10 TeV from Markarian 421

    K Okumura, A Asahara, GV Bicknell, PG Edwards, R Enomoto, S Gunji, S Hara, T Hara, S Hayashi, C Itoh, S Kabuki, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, S Maeda, A Maeshiro, Y Matsubara, Y Mizumoto, M Mori, M Moriya, H Muraishi, Y Muraki, T Naito, T Nakase, K Nishijima, M Ohishi, Patterson, JR, K Sakurazawa, R Suzuki, DL Swaby, K Takano, T Takano, T Tanimori, F Tokanai, K Tsuchiya, H Tsunoo, K Uruma, A Watanabe, S Yanagita, T Yoshida, T Yoshikoshi

    ASTROPHYSICAL JOURNAL   579 ( 1 ) L9 - L12  2002.11  [Refereed]

     View Summary

    We have observed Markarian 421 in 2001 January and March with the CANGAROO-II imaging Cerenkov telescope during an extraordinarily high state at TeV energies. From 14 hr of observations at very large zenith angles, similar to70degrees, a signal of 298 +/- 52 gamma-ray-like events (5.7 sigma) was detected at E &gt; 10 TeV, where a higher sensitivity is achieved than those of usual observations near the zenith, owing to a greatly increased collecting area. Under the assumption of an intrinsic power-law spectrum, we derived a differential energy spectrum dN/dE p (3.3 +/- 0.9(stat) +/- 0.3(syst)) x 10(-13) (E/10 TeV)(-(4.0+/-0.60.9, stat +/-0.3syst)) photons cm(-2) s(-1) TeV-1, which is steeper than those previously measured around 1 TeV and supports the evidence for a cutoff in the spectrum of Mrk 421. However, the 4 sigma excess at energies greater than 20 TeV in our data favors a cutoff energy of similar to8 TeV, at the upper end of the range previously reported from measurements at TeV energies.

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  • Performance of the ASTRO-E hard X-ray detector

    M Tashiro, T Kamae, K Makishima, T Takahashi, T Murakami, Y Fukazawa, M Kokubun, K Nakazawa, M Nomachi, A Yoshida, Y Ezoe, N Isobe, N Iyomoto, J Kataoka, J Kotoku, M Kouda, S Kubo, A Kubota, Y Matsumoto, T Mizuno, GM Madejski, Y Okada, N Ota, H Ozawa, G Sato, M Sugiho, M Sugizaki, Takahashi, I, H Takahashi, T Tamura, C Tanihata, Y Terada, Y Uchiyama, S Watanabe, K Yamaoka, D Yonetoku

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   49 ( 4 ) 1893 - 1897  2002.08  [Refereed]

     View Summary

    This paper summarizes the design and performance of the hard X-ray detector constructed for the ASTRO-E satellite. The detector utilizes the GSO/BGO well-type phoswich counters in a compound-eye configuration to achieve an extremely low background level of a few x 10(-5) counts s(-1) cm(-2)keV(-1) [1]. The GSO scintillators installed in the BGO active shield wells are sensitive to 30-600 keV photons, while the 2-mm-thick silicon PIN diodes, placed in front of each GSO crystal, cover the 10-60 keV energy band with a spectral resolution of similar to3.5-keV full-width at half-maximum. The design goals, of both low background and high energy resolution, in the hard X-ray bands were verified through the preflight calibration experiments.

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  • The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946

    R Enomoto, T Tanimori, T Naito, T Yoshida, S Yanagita, M Mori, PG Edwards, A Asahara, GV Bicknell, S Gunji, S Hara, T Hara, S Hayashi, C Itoh, S Kabuki, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, S Maeda, A Maeshiro, Y Matsubara, Y Mizumoto, M Moriya, H Muraishi, Y Muraki, T Nakase, K Nishijima, M Ohishi, K Okumura, Patterson, JR, K Sakurazawa, R Suzuki, DL Swaby, K Takano, T Takano, F Tokanai, K Tsuchiya, H Tsunoo, K Uruma, A Watanabe, T Yoshikoshi

    NATURE   416 ( 6883 ) 823 - 826  2002.04  [Refereed]

     View Summary

    Protons with energies up to similar to10(15) eV are the main component(1) of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking(2). Electrons are known to be accelerated to cosmic-ray energies in supernova remnants(3,4), and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi(0)), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in gamma-rays with a particular spectral-energy distribution(5,6). Here we report the observation of cascade showers of optical photons resulting from g-rays at energies of similar to10(12) eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.

    DOI PubMed

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  • Achievements of the ASTRO-E Hard X-ray Detector development

    M Tashiro, K Makishima, T Kamae, T Murakami, T Takahashi, Y Fukazawa, M Kokubun, K Nakazawa, M Nomachi, A Yoshida, Y Ezoe, N Isobe, N Iyomoto, J Kataoka, J Kotoku, M Kouda, S Kubo, A Kubota, Y Matsumoto, T Mizuno, Y Okada, N Ota, H Ozawa, G Sato, M Sugiho, M Sugizaki, Takahashi, I, H Takahashi, T Tamura, C Tanihata, Y Terada, Y Uchiyama, S Watanabe, K Yamaoka, D Yonetoku

    2001 IEEE NUCLEAR SCIENCE SYMPOSIUM, CONFERENCE RECORDS, VOLS 1-4   1   483 - 486  2002  [Refereed]

     View Summary

    The ASTRO-E Hard X-ray Detector utilized GSO/BGO well-type phoswich counters in compound-eye configuration [1], to achieve an extremely low background level of a few x 10(-5)counts s(-1) cm(-2) keV(-1). The GSO scintillators installed in the BGO active shield wells observes 30-600 keV photons, while silicon PIN diodes of 2 mm thick placed in front of each GSO crystal covers 10 - 60 keV photons with energy resolution of similar to3.5 keV FWHM. The design goals both of low background and high energy resolution in the hard X-ray bands were confirmed to be achieved through the preflight calibration experiments.

  • ブレーザーの他波長同時か観測と粒子加速への示唆

    片岡 淳 他

    天文月報   8月号 ( vol.95 ) 373  2002

  • Design study of CANGAROO-III, stereoscopic imaging atmospheric Cherenkov telescopes for sub-TeV gamma-ray detection

    R Enomoto, S Hara, A Asahara, GV Bicknell, PG Edwards, S Gunji, T Hara, J Jimbo, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, Y Matsubara, Y Mizumoto, M Mori, M Moriya, H Muraishi, Y Muraki, T Naito, T Nakase, K Nishijima, K Okumura, Patterson, JR, K Sakurazawa, DL Swaby, K Takano, T Tanimori, T Tamura, K Tsuchiya, K Uruma, S Yanagita, T Yoshida, T Yoshikoshi, A Yuki

    ASTROPARTICLE PHYSICS   16 ( 3 ) 235 - 244  2002.01  [Refereed]

     View Summary

    CANGAROO-III is an imaging atmospheric Cherenkov telescope array of four 10-m telescopes for very high energy (sub-TeV) gamma-ray astronomy. A design study of the CANGAROO-III telescope system was carried out using the Monte Carlo technique in order to optimize the pixel size and the telescope spacing. Studies were also made of observations at low elevation angles. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

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  • Variability timescales of TeV blazars observed in the ASCA continuous long-look X-ray monitoring

    C Tanihata, CM Urry, T Takahashi, J Kataoka, SJ Wagner, GM Madejski, M Tashiro, M Kouda

    ASTROPHYSICAL JOURNAL   563 ( 2 ) 569 - 581  2001.12  [Refereed]

     View Summary

    Three uninterrupted, long (lasting respectively 7, 10, and 10 days) ASCA observations of the well-studied TeV-bright blazars Mrk 421, Mrk 501, and PKS 2155-304 all show continuous strong X-ray flaring. Despite the relatively faint intensity states in two of the three sources, there was no identifiable quiescent period in any of the observations. Structure function analysis shows that all blazars have a characteristic timescale of similar to1 day, comparable to the recurrence time and to the timescale of the stronger flares. On the other hand, examination of these flares in more detail reveals that each of the strong flares is not a smooth increase and decrease but exhibits substructures of shorter flares having timescales of similar to 10 ks. We verify via simulations that in order to explain the observed structure function, these shorter flares ("shots") are unlikely to be fully random, but in some way are correlated with each other. The energy dependent cross-correlation analysis shows that interband lags are not universal in TeV blazars. This is important since in the past only positive detections of lags were reported. In this work, we determine that the sign of a lag may differ from flare to flare; significant lags of both signs were detected from several flares, while no significant lag was detected from others. However, we also argue that the nature of the underlying component can affect these values. The facts that all flares are nearly symmetric and that fast variability shorter than the characteristic timescale is strongly suppressed, support the scenario where the light crossing time dominates the variability timescales of the day-scale flares.

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  • Characteristic X-ray variability of TeV blazars: Probing the link between the jet and the central engine

    J Kataoka, T Takahashi, SJ Wagner, N Iyomoto, PG Edwards, K Hayashida, S Inoue, GM Madejski, F Takahara, C Tanihata, N Kawai

    ASTROPHYSICAL JOURNAL   560 ( 2 ) 659 - 674  2001.10  [Refereed]

     View Summary

    We have studied the rapid X-ray variability of three extragalactic TeV gamma -ray sources : Mrk 421, Mrk 501, and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or Rossi X-Ray Timing Explorer observations between 1993 and 1998, we have investigated the variability in the time domain from 10(3) to 10(8) s. For all three sources, both the power spectrum density (PSD) and the structure function (SF) show a rollover with a timescale of the order of 1 day or longer, which may be interpreted as the typical timescale of successive flare events. Although the exact shape of turnover is not well constrained and the low-frequency (long timescale) behavior is still unclear, the high-frequency (short timescale) behavior is clearly resolved. We found that, on timescales shorter than 1 day, there is only small power in the variability, as indicated by a steep power spectrum density of f(-2 similar to -3). This is very different from other types of mass-accreting black hole systems, for which the short-timescale variability is well characterized by a fractal, flickering-noise PSD (f(-1 similar to -2)). The steep PSD index and the characteristic timescale of flares imply that the X-ray-emitting site in the jet is of limited spatial extent : D greater than or equal to 10(17) cm distant from the base of the jet, which corresponds to greater than or equal to 10(2) Schwarzschild radii for 10(7-10) M-circle dot black hole systems.

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  • Spectral evolution of PKS 2155-304 during the ASCA long-look campaign

    M Kouda, C Tanihata, T Takahashi, M Tashiro, J Kataoka

    NEW CENTURY OF X-RAY ASTRONOMY   251   376 - 377  2001  [Refereed]

     View Summary

    We collected all light curves of the TeV blazar PKS 2155-304, spanning over 12 years, obtained by both Ginga and ASCA. Taking the advantage that Ginga covers a higher energy range compared to ASCA, we confirmed the amplitude of the variations being larger at higher energies, which is consistent with the synchrotron picture of the X-ray jet. We also report on the recent ASCA continuous 10-day observation of this source. In spite of its low flux compared to previous observations, we detected significant daily variations, and found that there was actually no particular quiescent period throughout our observation.

  • 活動銀河核からの高エネルギー放射:相対論的ジェットの物理

    片岡 淳

    日本物理学会誌   vol.56 no.3 ( 3 ) 189 - 194  2001

    DOI CiNii

  • Rapid synchrotron flares from BL Lacertae detected by ASCA and RXTE

    C Tanihata, T Takahashi, J Kataoka, GM Madejski, S Inoue, H Kubo, F Makino, Mattox, JR, N Kawai

    ASTROPHYSICAL JOURNAL   543 ( 1 ) 124 - 130  2000.11  [Refereed]

     View Summary

    We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray, optical, and gamma -ray emission, with its 2-10 keV flux peaking at similar to3.3 x 10(-11) ergs cm(-2) s(-1). This is more than 3 times higher than the value measured by ASCA in 1995. Ne detected two rapid flares that occurred only in the soft X-ray band, while the hard X-ray flux also increased, but decayed with a much longer timescale. Together with the requirement of a very steep and varying power law dominating the soft X-ray band in addition to the hard power law, we suggest that both the high-energy end of the synchrotron spectrum and the hard inverse Compton spectrum were visible in this source during the outburst. We discuss the possible origins of the observed variability timescales, and interpret the short timescales of the soft X-ray variability as reflecting the size of the emission region.

  • Complex spectral variability from intensive multiwavelength monitoring of Markarian 421 in 1998

    T Takahashi, J Kataoka, G Madejski, J Mattox, CM Urry, S Wagner, F Aharonian, M Catanese, L Chiappetti, P Coppi, B Degrange, G Fossati, H Kubo, H Krawczynski, F Makino, H Marshall, L Maraschi, F Piron, R Remillard, F Takahara, M Tashiro, H Terasranta, T Weekes

    ASTROPHYSICAL JOURNAL   542 ( 2 ) L105 - L109  2000.10  [Refereed]

     View Summary

    We conducted a multifrequency campaign for the TeV blazar Markarian 421 in 1998 April. The campaign started from a pronounced high-amplitude flare recorded by BeppoSAX and Whipple; the ASCA observation started 3 days later. In the X-ray data, we detected multiple flares, occurring on timescales of about 1 day. ASCA data clearly reveal spectral variability. The comparison of the data from ASCA, the Extreme Ultraviolet Explorer, and the Rossi X-Ray Timing Explorer indicates that the variability amplitudes in the low-energy synchrotron component are larger at higher photon energies. In TeV gamma -rays, large intraday variations-which were correlated with the X-ray flux-were observed when results from three Cerenkov telescopes were combined. The rms variability of TeV gamma -rays was similar to that observed in hard X-rays, above 10 keV. The X-ray light curve reveals flares that are almost symmetric for most cases, implying that the dominant timescale is the light crossing time through the emitting region. The structure function analysis based on the continuous X-ray light curve of 7 days indicates that the characteristic timescale is similar to0.5 days. The analysis of ASCA light curves in various energy bands appears to show both soft (positive) and hard (negative) lags. These may not be real, as systematic effects could also produce these lags, which are all much smaller than an orbit. If the lags of both signs are red, these imply that the particle acceleration and X-ray cooling timescales are similar.

  • Capability of the ASTRO-E Hard X-ray Detector for high-energy transients and gamma-ray bursts

    Y Terada, K Yamaoka, M Kokubun, J Kotoku, T Mizuno, J Kataoka, T Takahasi, T Murakami, K Makishima, T Kamae

    FIFTH COMPTON SYMPOSIUM   510   667 - 670  2000  [Refereed]

     View Summary

    The Hard X-Ray Detector (HXD) is one of the instruments on board ASTRO-E, scheduled for lanch in January-February 2000. The HXD consists of 16 Well-type phoswich counters, surrounded by 20 active shield counters (Anti Coincidence Counters: Anti-Counters). It covers the energy range 10-600 keV with a very low background. Because the Anti-Counters are made of thich high-Z material with a very large geometrical area, they retain a large effective area up to high energies. Therefore the Anti-Counters can be used for monitoring high-energy transient sources and gamma-ray bursts. In this paper, the ail sky monitoring function with the Anti-Counters and the result of their ground calibration tests are described.

  • Variability pattern and the spectral evolution of the BL lacertae object PKS 2155-304

    J Kataoka, T Takahashi, F Makino, S Inoue, GM Madejski, M Tashiro, CM Urry, H Kubo

    ASTROPHYSICAL JOURNAL   528 ( 1 ) 243 - 253  2000.01  [Refereed]

     View Summary

    The TeV blazar PKS 2155 - 304 was monitored with the X-ray satellite ASCA in 1994 May as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a lame flare, in which the 2-10 keV flux changed by a factor of 2 on a timescale of 3 x 10(4) s. During the hare, the increase in the hard X-ray flux clearly preceded that observed in the soft X-rays, with the spectral evolution tracking a "clockwise loop" in the flux versus photon index plane. Ascribing the energy-dependent variability to differential synchrotron cooling of relativistic electrons, we estimate the magnetic field B in the emission region. We tested two different methods of comparing the time series in various X-ray bands: (1) fitting the light curves to a Gaussian function and searching for the time shift of the peak of the flare, and (2) calculating the discrete correlation function. Both methods yielded a consistent solution of B similar to 0.1 G; We also found that the flare amplitude becomes larger as the photon energy increases, while the duration of the flare stays roughly constant throughout the ASCA energy band (0.7-7.5 keV). In the framework of the time-dependent synchrotron self-Compton model in a homogeneous region, we consider a flare where the maximum Lorentz factor (gamma(max)) of the injected electrons increases uniformly throughout the emission volume. The temporal evolution of spectra as well as the light curves were reproduced with the physical parameters self-consistently determined from seven observables. We obtained B similar to 0.1-0.2 G and a region size R similar to 10(-2) pc for relativistic beaming with a Doppler factor of delta similar to 20-30. We discuss the significance of light-travel time effects.

  • A study of high energy emission from the TeV blazar Mrk 501 during multiwavelength observations in 1996

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartmann, GM Madejski, P Sreekumar, SJ Wagner

    BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES   25 ( 3-4 ) 737 - 740  2000  [Refereed]

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA. EGRET, Whipple, and optical telescopes. We report here for the first time the detection of GeV gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). Higher flux was also observed in April/May 1996, with 4.0 sigma for E &gt; 100 MeV, and 5.2 sigma for E &gt; 500 MeV. We find that the multiband spectrum in March 1996 is consistent with that calculated from a one-zone SSC model, except for the extremely 'flat' TeV spectrum. We show that this flat spectrum cannot be explained by either 2nd order Comptonization or the contribution of the 'seed' IR photons from the host galaxy. (C) 2000 COSPAR. Published by Elsevier Science Ltd.

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  • Thick and large area PIN diodes for hard X-ray astronomy

    N Ota, T Murakami, M Sugizaki, H Kaneda, T Tamura, H Ozawa, T Kamae, K Makishima, T Takahashi, M Tashiro, Y Fukazawa, J Kataoka, K Yamaoka, S Kubo, C Tanihata, Y Uchiyama, K Matsuzaki, N Iyomoto, M Kokubun, T Nakazawa, A Kubota, T Mizuno, Y Matsumoto, N Isobe, Y Terada, M Sugiho, T Onishi, H Kubo, H Ikeda, M Nomachi, T Ohsugi, M Muramatsu, H Akahori

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   436 ( 1-2 ) 291 - 296  1999.10  [Refereed]

     View Summary

    Thick and large area PIN diodes for the hard X-ray astronomy in the 10-60 keV range are developed. To cover this energy range in a room temperature and in a low background environment, Si PIN junction diodes of 2 mm in thickness with 2.5 cm(2) in effective area were developed, and will be used in the bottom of the Phoswich Hard X-ray Detector (HXD), on-board the ASTRO-E satellite. Problems related to a high purity Si and a thick depletion layer during our development and performance of the PIN diodes are presented in detail. (C) 1999 Elsevier Science B.V. All rights reserved.

    DOI

    Scopus

    14
    Citation
    (Scopus)
  • Multiwavelength observations of the TeV blazar Mrk 501 in March 1996. The first report of the detection by EGRET

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartman, GM Madejski, P Sreekumar, SJ Wagner

    ASTROPARTICLE PHYSICS   11 ( 1-2 ) 149 - 151  1999.06  [Refereed]

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA, EGRET, Whipple, and optical telescopes. We report here for the first time the detection of a GeV gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). A higher flux was also observed in April/May 1996, with 4.0 sigma significance for E &gt; 100 MeV, and 5.2 sigma significance for E &gt; 500 MeV. We find that the multiband spectrum in March 1996 is consistent with that calculated from a one-zone SSC model, except for the extremely 'flat' TeV spectrum. We show that the discrepancy cannot be explained by either second order Comptonization or the contribution of the 'seed' IR photons from the host galaxy. (C) 1999 Elsevier Science B.V. All rights reserved.

    DOI

    Scopus

    14
    Citation
    (Scopus)
  • Activation of the ASTRO-E hard x-ray detector in low earth orbit

    M Kokubun, Y Fukazawa, E Idesawa, J Kataoka, T Kamae, K Matsuzaki, T Mizuno, Y Saito, T Takahashi, K Takizawa, M Tashiro, T Tamura, A Yoshida

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   46 ( 3 ) 371 - 376  1999.06  [Refereed]

     View Summary

    ASTRO-E Hard X-ray Detector (HXD) is characterized by well-type phoswich counters[1] in a compound-eye configuration which reduce the detector background to lower level than any other past hard X-ray mission. When operating in Low Earth Orbit, the expected background of the HXD is an order of 10(-5) counts/s/kev/cm(2), mainly caused from the radioactivity induced within the detector materials by geomagnetically trapped protons. Results are presented from measurements of induced radioactivity in two phoswich scintillators, GSO (Gd2SiO5:Ce 0.5% mol) and EGO (Bi4Ge3O12), irradiated by mono-energetic protons at an accelerator facility. Radiation transport computer codes are used to build the detector response functions for emissions from decays of spallation products. Based on the comparison between experimental and simulation results, the activation background level of HXD in the orbit is estimated.

    DOI

    Scopus

    27
    Citation
    (Scopus)
  • High-energy emission from the TeV blazar Markarian 501 during multiwavelength observations in 1996

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartman, GM Madejski, P Sreekumar, SJ Wagner

    ASTROPHYSICAL JOURNAL   514 ( 1 ) 138 - 147  1999.03  [Refereed]

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in 1996 March with ASCA, EGRET, Whipple, and optical telescopes. The X-ray flux observed with ASCA was 5 times higher than the quiescent level and gradually decreased by a factor of 2 during the observation in 1996 March. In the X-ray band, a spectral break was observed around 2 keV. We report here for the first time the detection of high-energy gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). Higher flux was also observed in 1996 April-May, with 4.0 sigma significance for E &gt; 100 MeV and 5.2 sigma significance for E &gt; 500 MeV. The gamma-ray spectrum was measured to be flatter than most of the gamma-ray blazars. We find that the multiband spectrum in 1996 is consistent with that calculated from a one-zone synchrotron self-Compton (SSC) model in which X-rays are produced via synchrotron emission and gamma-rays are produced via inverse Compton scattering of synchrotron photons in a homogeneous region. The flux of TeV gamma-rays is consistent with the predictions of the model if the decrease of the Compton scattering cross section in the Klein-Nishina regime is considered. In the context of this model, we investigate the values of the magnetic field strength and the beaming factor allowed by the observational results. We compare the 1996 March multiwavelength spectrum with that in the flare state in 1997 April. Between these two epochs, the TeV flux increase is well correlated with that observed in keV range. The keV and TeV amplitudes during the 1997 April hare are accurately reproduced by a one-zone SSC model, assuming that the population of synchrotron photons in 1996 are scattered by newly injected relativistic electrons having maximum energies of gamma(max) similar to 6 x 10(6). However, the TeV spectrum observed during the 1996 March campaign is flatter than predicted by our models. We find that this cannot be explained by either higher order Comptonization or the contribution of the "seed" IR photons from the host galaxy for the first-order external radiation. Comptonization, but we cannot exclude possible effects of the IR photons that may arise in the parsec-size tori postulated to exist in active galactic nuclei.

  • Variability pattern and the spectral evolution of blazars

    J. Kataoka

    Astronomische Nachrichten   320 ( 4-5 ) 309  1999

     View Summary

    The rapid, large-amplitude variability and very wide spectral energy distribution are marked features of blazars. To investigate the nature of these extreme particle accelerators, a number of multi-frequency campaigns have been conducted so far. Recent campaigns of the TeV blazars, Mrk 421 and Mrk 501, revealed a correlated flare between the keV X-ray and TeV γ-ray bands, providing valuable information for the emission mechanism of blazars. However, theoretical efforts lag behind the observations. Most of the previous works consider only the steady state emission, in spite of rapid blazars' variability. To understand the time evolution of blazar spectra quantitatively, we developed a time-dependent model based on the synchrotron self-Compton (SSC) emission in a homogeneous region, incorporating the radiative cooling and acceleration process properly. In this paper, we apply this model to the X-ray flare of PKS 2155-304 observed in 1994. We obtained the satisfactory fit for both spectra and light curves with the magnetic field B ∼ 0.1 - 0.2 G and the region size R ∼ 10-2 pc, assuming a Doppler beaming factor of δ ∼ 20 - 30.

    DOI

    Scopus

  • Activation of the ASTRO-E hard X-ray detector in low Earth orbit

    Kokubun M, Fukazawa Y, Idesawa E, Kataoka J, Kamae T, Matsuzaki K, Mizuno T, Saito Y, Takahashi T, Takizawa K, Tashiro M, Tamura T, Yoshida A

    IEEE Nuclear Science Symposium and Medical Imaging Conference   1   227 - 232  1999  [Refereed]

     View Summary

    ASTRO-E Hard X-ray Detector (HXD) is characterized by well-type phoswich counters in a compound-eye configuration which reduce the X-ray and non X-ray background to lower level than any other past hard X-ray missions. When operating in Low Earth Orbit, the expected background of the HXD is an order of 10-5[counts/s/keV/cm2], mainly caused from the radioactivity induced within the detector materials by nuclear interactions with geomagnetically trapped protons. Results are presented from measurements of induced radioactivity in two phoswich scintillators, GSO and BGO, irradiated by mono-energetic protons at an accelerator facility. Radiation transport computer codes are used to build the detector response functions against emissions from decays of spallation products. Based on the comparison of experimental and simulation results, the activation background level of HXD in the orbit is estimated.

  • Electronic system for the Astro-E Hard X-ray Detector

    T. Takahashi, M. Nomachi, Y. Fukazawa, M. Tashiro, H. Ezawa, M. Hamaya, M. Horii, N. Isobe, N. Iyomoto, J. Kataoka, T. Kamae, G. Kawaguchi, H. Kubo, S. Kubo, A. Kubota

    Proceedings of SPIE - The International Society for Optical Engineering   3445   155 - 168  1998  [Refereed]

     View Summary

    Hard X-ray Detector (HXD) is one of three instruments on the fifth Japanese X-ray astronomy satellite, Astro-E, scheduled for launch in 2000. The sensitivity of the Astro-E HXD will be higher by more than one order of magnitude than that of any previous instrument between 10 keV and several 100 keV. The electronic system is designed to handle many independent data channels from the HXD within the limitation of size and power consumption required in Astro-E. In this paper, we will present the design and the preliminary performance of the processing electronic system.

  • Verification of the Astro-E Hard X-ray Detector based on newly developed Ground Support Equipment

    J Kataoka, M Nomachi, T Takahashi, G Kawaguchi, Y Terada, T Murakami, C Tanihata, Y Uchiyama, K Yamaoka, Y Fukazawa, T Kamae, K Makishima, M Tashiro, H Kubo

    EUV, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY IX   3445   143 - 154  1998  [Refereed]

     View Summary

    We report the first results of the ground test of the Hard X-ray Detector (HXD) on board the Astro-E mission, by means of the newly developed Ground Support Equipment (GSE). Astro-E will be launched in 2000 by a Japanese M-V rocket. In order to verify the detector system during the limited time before launch, fast and versatile GSE is necessary. For this, we have developed a flexible test system based on nine VME I/O boards for a SUN workstation. These boards carry reconfigurable Field Programmable Gate Arrays (FPGAs) with 50,000 gates, together with 1 Mbyte SRAM devices tightly coupled to each FPGA device. As an application of using this GSE, we have tested the performance of a phoswich unit of the Flight Model of the HXD. In this paper, we present a schematic view of the GSE highlighting the functional design, and the results of our ground test of the HXD-sensor under the high count rate environment (similar to 10 kHz/unit) expected in orbit.

  • Integration of the readout electronics for the ASTRO-E hard X-ray detector

    H. Ozawa, J. Kataoka, T. Murakami, M. Sugizaki, T. Takahashi, K. Yamaoka, H. Ezawa, Y. Fukazawa, T. Kamae, K. Makishima, T. Mizuno, K. Nakazawa, S. Osone, H. Ikeda, K. Tsukada, H. Kubo

    Proceedings of SPIE - The International Society for Optical Engineering   3115   235 - 243  1997  [Refereed]

     View Summary

    We have developed the analog electronics of the ASTRO-E Hard X-ray Detector (HXD). The ASTRO-E is the fifth Japanese X-ray astronomy satellite scheduled for launch in 2000. Three experiments will be on board the satellite, one of which being the HXD. The detector consists of 16 units of well-type phoswich counters with silicon PIN diodes embedded therein, and covers the energy range of 10 ∼ 600 keV with photon collecting area of about 350 cm2. The readout circuit for the HXD handles many signal channels (96 channels in total) under the limitation of power consumption and size set by the satellite. To meet the limitations, we have developed two types of bipolar semicustom LSIs. One is the pulse-shape discriminator (PSD-LSI) for phoswich counters and the other is for silicon PIN diodes (PIN-LSI). The PSD-LSI selects clean GSO hits and reduces the off-aperture X-rays and internal background of the detector down to 10-5 c/s/cm2/keV. One PIN-LSI handles signals from two PIN diodes, each consisting of an amplifier, a peak-hold circuit, and a comparator to trigger the readout system. Test pieces of these LSIs meet the specifications such as power consumptions and linearities. Using PIN-LSI, we could successfully obtain X-ray spectrum from 241Am with a PIN diode.

    DOI J-GLOBAL

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  • Development of the hard X-ray detector for the ASTRO-E mission

    T Takahashi, H Ezawa, Y Fukazawa, M Hirayama, E Idesawa, H Ikeda, Y Ishisaki, N Iyomoto, T Kamae, J Kataoka, H Kaneda, H Kubo, K Makishima, K Matsushita, K Matsuzaki, T Mizuno, T Murakami, K Nagata, S Nakamae, M Nomachi, H Obayashi, T Ohtsuka, H Ozawa, Y Saito, M Sugizaki, T Tamura, M Tashiro, N Tsuchida, K Tsukada, A Yoshida

    ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES   120 ( 4 ) C645 - C648  1996.12  [Refereed]

     View Summary

    The Hard X-ray Detector (HXD) is one of three instruments on the fifth Japanese X-ray astronomy satellite, ASTRO-E, scheduled for launch in 2000. The HXD consists of a 4x4 = 16 modular assembly of identical counters, each consisting of a combination of YAP(or GSO)/BGO well-type phoswich counters and silicon PIN diodes. The field of view of the detector for high energy photons is restricted to 4 degrees x 4 degrees by active collimators made of BGO and the fov for low energy photons is restricted to 0.5 degrees x 0.5 degrees by the fine passive collimators made of phosphor bronze. The detector is characterized by a low background reaching severalx10(-6) c/s/cm(2)/keV. Combined with the other two instruments for soft X-ray observations (0.5-12 keV), the ASTRO-E mission will cover the entire range of soft and hard X-rays with the highest sensitivity ever achieved. Furthermore, thick EGO counters which surround the 4x4 matrix of well-type phoswich counters act as a gamma-ray burst detector in the energy band of 100-2000 keV.

  • ASCA observation of an X-ray/TeV flare from the BL Lacertae object Markarian 421

    T Takahashi, M Tashiro, G Madejski, H Kubo, T Kamae, J Kataoka, T Kii, F Makino, K Makishima, N Yamasaki

    ASTROPHYSICAL JOURNAL   470 ( 2 ) L89 - L92  1996.10  [Refereed]

     View Summary

    We observed the BL Lac object Mrk 421 with the X-ray satellite ASCA in 1994 as part of a multifrequency observation. The 24 hr observation was conducted 1 day after the onset of a TeV flare detected by the Whipple Observatory and detected an X-ray flare, with no apparent variability in the optical, UV, and EGRET GeV flux. The ASCA 2-10 keV flux peaked at 3.7 x 10(-10) ergs cm(-2) s(-1) and then decreased to 1.8 x 10(-10) ergs cm(-2) s(-1) with a doubling timescale of similar to 12 hr. The shape of the X-ray spectrum varied during the observation, such that the hard X-rays always led the soft X-rays, both in brightening and dimming of the source, with a lag of the 0.5-1 keV photons versus those in the 2-7.5 keV band of similar to 1 hr. The rapid TeV variability indicates a compact TeV-producing region, suggesting relativistic beaming with a Doppler factor delta greater than or equal to 5. The correlation of the flux in the X-ray and the TeV bands indicates that a high-energy tail of a single electron population is responsible for both X-rays and TeV gamma-rays, with radio, IR, UV and X-rays produced via the synchrotron process and GeV and TeV gamma-rays produced via Comptonization. Under the assumption that the ''soft lag'' observed in the X-ray band is due to the synchrotron-lifetime effects, with delta = 5, we calculate the magnetic field for the X-ray-producing region to be similar to 0.2 G. The Lorentz factors gamma(el) of the electrons responsible for the emission in the keV and TeV bands are similar to 10(6), consistent with the values implied by the Klein-Nishina limit.

  • Gamma-ray burst monitoring with the hard X-ray detector onboard the ASTRO-E mission

    A Yoshida, H Ezawa, Y Fukazawa, M Hirayama, E Idesawa, H Ikeda, Y Ishisaki, N Iyomoto, T Kamae, J Kataoka, H Kaneda, H Kubo, K Makishima, K Matsushita, K Matsuzaki, T Mizuno, T Murakami, K Nagata, S Nakamae, M Nomachi, H Obayashi, T Otsuka, H Ozawa, Y Saito, M Sugizaki, T Takahashi, T Tamura, M Tashiro, N Tsuchida, K Tsukada

    GAMMA-RAY BURSTS - 3RD HUNTSVILLE SYMPOSIUM, PTS 1 AND 2   ( 384 ) 870 - 874  1996  [Refereed]

     View Summary

    ASTRO-E is the fifth Japanese X-ray astronomy satellite scheduled to be launched in year 2000. The satellite will carry three scientific instruments, one of which is the Hard X-ray Detector (HXD). HXD will cover the 10-600 keV band with low background of several x 10(-6)c/s/cm(2)/keV. This will be achieved by the well-type phoswich counter technique together with large active shield counters of EGO (about 1200 cm(2)/side), which are also capable to detect GRBs in the 100-2000 keV band. About 100 GRBs are expected to be detected per year with HXD.

  • ASCA Observations of X-ray/TeV Flare from Mkn 421

    Takahashi et a

    Mem. Della Soc.Astr. Ital.   67   533  1996

  • A SEARCH FOR MASSIVE NEUTRAL BOSONS IN ORTHOPOSITRONIUM DECAY

    T MAENO, M FUJIKAWA, J KATAOKA, Y NISHIHARA, S ORITO, K SHIGEKUNI, Y WATANABE

    PHYSICS LETTERS B   351 ( 4 ) 574 - 578  1995.06  [Refereed]

     View Summary

    We have searched for an exotic decay of orthopositronium into a single photon and a short-lived neutral boson in the hitherto unexplored mass region above 900 keV/c(2), by noting that this decay is one of few remaining candidates which could explain the discrepancy of the orthopositronium decay rate. A high-resolution measurement of the associated photon energy spectrum was carried out with a germanium detector to search for a sharp peak from this two-body decay. Our negative result provides an upper limit of 2.0 x 10(-4) on the branching ratio of such a decay in the mass region from 847 to 1013 keV/c(2), and excludes the possibility of this decay mode explaining the discrepancy in the orthopositronium decay rate.

    DOI

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▼display all

Books and Other Publications

  • 薬物動態を可視化する放射化イメージング:宇宙の元素合成を医療に応用

    越川七星, 片岡淳( Part: Joint author)

    月刊化学(化学同人)  2023.05

  • 広帯域 X 線・ガンマ線による薬剤可視化へ向けた新技術

    越川七星, 増渕美穂, 片岡 淳( Part: Joint author)

    応用物理学会放射線分科会会誌 vol.48  2023.04

  • CT開発の最先端 Photon-Counting CT

    有元 誠, 川嶋 広貴, 小林 聡, 片岡 淳( Part: Joint author)

    日獨医報 vol.66、No.1  2022.07

  • コンプトンカメラを用いたアクティブ動態イメージング

    片岡 淳, 小俣陽久, 増渕美穂, 越川七星( Part: Joint author)

    Medical Imaging Technology, vol.39、No.5  2021.11

  • Spectral Photon-Counting CT System Based on Si-PM Coupled with Novel Ceramic Scintillators

    H.Kiji, T.Toyoda, J.Kataoka, M.Arimoto, S.Terazawa, S.Shiota, H.Ikeda( Part: Joint author)

    Radiation Detection Systems – Medical Imaging, Industrial Testing and Security Applications, CRC press  2021.04 ISBN: 9781003218364

  • Activity bubbling up

    Jun Kataoka( Part: Sole author)

    Nature Astronomy  2020.10

  • 宇宙物理学ハンドブック (朝倉書店)

    高原文郎, 家正則, 小玉英雄, 高橋忠幸, 集( Part: Contributor)

    2020.02 ISBN: 9784254131277

▼display all

Presentations

  • 薬物動態可視化へむけたX線ガンマ線イメージング の展開

    片岡淳  [Invited]

    第2回短寿命RI利用研究シンポジウム 

    Presentation date: 2024.12

  • セラノスティクスに向けた薬物動態可視化の試み

    片岡淳  [Invited]

    第4回 日本量子医科学会 学術大会 

    Presentation date: 2024.12

  • 放射化を用いた薬物動態可視化への挑戦

    片岡淳  [Invited]

    日本放射化学会第68回討論会 

    Presentation date: 2024.09

  • Radiation imaging for the future nuclear medicine and particle therapy

     [Invited]

    Presentation date: 2024.04

    Event date:
    2024.04
     
     
  • History of satellite and sensor development at Kawai-lab: FY 2001-2008

    Jun KATAOKA  [Invited]

    Transients and variables workshop 

    Presentation date: 2023.03

  • ガンマ線イメージングが拓く近未来:宇宙から医療・大気・資源探査へ

    片岡淳  [Invited]

    第83回 応用物理学会秋季年会(2022) 

    Presentation date: 2022.09

  • X線ガンマ線イメージングでつなぐ宇宙と医療

    片岡淳  [Invited]

    日本コンピュータ外科学会大会 

    Presentation date: 2022.06

  • X線ガンマ線イメージングが切り拓く近未来 - 宇宙物理と放射線治療の架け橋へ -

    片岡淳  [Invited]

    日本医学物理学会学術大会 

    Presentation date: 2022.04

  • X線ガンマ線イメージングの医療応用

    片岡淳  [Invited]

    原子・分子・光科学(AMO)討論会 

    Presentation date: 2021.06

  • Spectral Photon Counitng CT as a new diagnostic tool for medical innovation

    Jun KATAOKA  [Invited]

    Tsukuba Conference 

    Presentation date: 2019.10

  • 核医学や高精度陽子線治療にむけたイメージング装置の開発

    片岡淳  [Invited]

    放射線基礎セミナー  アイソトープ協会

    Presentation date: 2018.07

  • 宇宙から医療まで:放射線イメージングの最前線

    片岡淳  [Invited]

    第65回応用物理学会・特別シンポジウム  応用物理学会

    Presentation date: 2018.03

  • “手のひらサイズ”コンプトンカメラを用いた3D in vivo イメージングへの挑戦

    片岡淳  [Invited]

    第13回小動物インビボイメージング研究会  日本核医学会

    Presentation date: 2017.07

  • X-ray Observations of the Fermi Bubbles and Loop-I Structures

     [Invited]

    Roaming Baryons in the Universe 

    Presentation date: 2017.07

  • MPPC-based scintillation detectors for innovative X-ray and gamma-ray imaging

    Jun Kataoka  [Invited]

    Presentation date: 2017.03

  • MPPC を用いた放射線イメージングの最前線-宇宙・環境・医療のクロスオーバー

    片岡 淳  [Invited]

    山形大学理学部セミナー 

    Presentation date: 2016.07

  • Si-PM-based Scintillation Detectors for Next Generation Radiology Imaging

    J.Kataoka  [Invited]

    EMN2016 - Photodetectors' Meeting  (Cancun, Mexico) 

    Presentation date: 2016.06

  • High Energy Emission from the GC and Fermi Bubble

     [Invited]

    Presentation date: 2015.07

  • Observational aspects of AGN jets at high energy

     [Invited]

    IAU Symposium 313 

    Presentation date: 2014.09

  • Recent Progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging

     [Invited]

    Symposium on Radiation Measurements and Applications (SORMA XV 2014) 

    Presentation date: 2014.06

  • Suzaku X-ray Observations of the Diffuse X-ray Emission across the Fermi Bubbles' Edges

     [Invited]

    66th Fujiwara seminar: X-raying the Gamma-ray universe &#8211; CTA X-ray Link Meeting 

    Presentation date: 2013.11

  • X-ray observations of the Fermi bubble

     [Invited]

    The Fermi Bubbles: Theory and Observations 

    Presentation date: 2013.04

  • Non-Blazar AGN and AGN Unification in the Fermi Era

     [Invited]

    Fermi Symposium 2012 

    Presentation date: 2012.10

  • Expected radiation damage of reverse-type APDs for the Astro-H mission

    IEEE Nuclear Science Symposium and Medical Imaging 

    Presentation date: 2012.10

  • Fermi LAT observations of AGN &amp; unID sources: Update

     [Invited]

    3rd Fermi Asian Network (FAN3) 

    Presentation date: 2012.06

  • Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    Vienna Conference on Instrumentation 2013 (VCI2013) 

    Presentation date: 2012.02

  • Fermi-LAT observations of Misaligned AGN; Towards AGN Unification

     [Invited]

    2nd Fermi Asian Network (FAN2) 

    Presentation date: 2011.08

  • Broad Line Radio Galaxies Observed with Fermi LAT; Disentangling the Jet and the Disk Emission Spectra

    Fermi Symposium 2011 

    Presentation date: 2011.05

  • 大面積APDアレーの開発と次世代PET技術への展望

     [Invited]

    日本応用物理学会 春季年会 

    Presentation date: 2009.03

  • 「純国産」APD-PETの実用化にむけて

     [Invited]

    H20 次世代PET研究会 

    Presentation date: 2009.01

  • Chandra Reveals Twin X-ray Jets in the Powerful FR II Radio Galaxy 3C 353

    International Symposium on High Energy Gamma-ray Astronomy 

    Presentation date: 2008.07

  • Characterizing X-ray Variability of TeV Blazars

     [Invited]

    Workshop on Blazar Variability across the Electromagnetic Spectrum 

    Presentation date: 2008.04

  • High Energy Observations of AGN Jets and Their Future Prospects

     [Invited]

    Accelerators in the Universe 

    Presentation date: 2008.03

  • Suzaku View of Powerful Gamma-ray Quasars and TeV Blazars

     [Invited]

    The Suzaku X-ray Universe 

    Presentation date: 2007.12

  • High Energy Observations of AGN Jets and their Implications

     [Invited]

    High Energy Observations of AGN Jets and their Implications 

    Presentation date: 2007.12

  • 多波長観測から探るジェットの加速・輸送・組成について

     [Invited]

    3 学会合同プラズマ共催セッション 特別講演 

    Presentation date: 2007.09

  • Suzaku View of Powerful Gamma-ray Quasars

     [Invited]

    High Energy Gamma-rays from Relativistic Outflows 

    Presentation date: 2007.09

  • APD-PET へむけた開発の現状

     [Invited]

    H19 次世代PET 研究会 

    Presentation date: 2007.07

  • ジェットの本質的理解にむけて;最近の話題から

     [Invited]

    VSOP2 グループセミナー 

    Presentation date: 2007.06

  • 活動銀河ジェットの粒子加速とエネルギー輸送・内部組成について

     [Invited]

    東北大学天文学教室談話会 

    Presentation date: 2007.04

  • Suzaku Observarion of AGN and Synnergy with GLAST

     [Invited]

    First GLAST Symposium 

    Presentation date: 2007.02

  • APD 開発の現状と今後

     [Invited]

    次世代PET 研究会 

    Presentation date: 2007.01

  • APD に関する研究紹介とPET 利用への道のり

     [Invited]

    放射線医学研究所 定例セミナー 

    Presentation date: 2006.12

  • APD 開発の現状—宇宙利用から高速PET まで

     [Invited]

    第2回 次世代光センサーワークショップ 

    Presentation date: 2006.12

  • Broad-Band Emission of Large-Scale Jets in AGNs

     [Invited]

    Challenges of Relativistic Jets 

    Presentation date: 2006.06

  • Acceleration and Non-thermal Phenomena in AGN jets

     [Invited]

    High Energy Astrophysics in the NeXT Decade 

    Presentation date: 2006.06

  • 活動銀河核ジェットの物理:観測からの制限

     [Invited]

    早稲田大学 理論宇宙研セミナー 

    Presentation date: 2006.06

  • Suzaku 衛星によるAGN の観測と将来展望

     [Invited]

    高エネルギーガンマ線天文学の展望 

    Presentation date: 2006.03

  • 宇宙の一番星ガンマ線バースト偏光X線観測衛星の提案

     [Invited]

    「れいめい」成果報告会 JAXA 宇宙科学研究本部 

    Presentation date: 2005.11

  • TeV ブレーザーの多波長観測から探る、相対論的ジェットの物理

     [Invited]

    東海大学理学部セミナー 

    Presentation date: 2005.11

  • What can GLAST tell us about AGN jets?

     [Invited]

    GLAST Science Workshop 

    Presentation date: 2005.11

  • 相対論的ジェットにおける粒子加速とエネルギー輸送の研究

     [Invited]

    日本天文学会 研究奨励賞受賞講演 

    Presentation date: 2005.03

  • X-ray Emission Properties of Relativistic Jets in AGN

     [Invited]

    International Workshop on Magnetohydrodynamic (MHD) Accretion Flow and Jets 

    Presentation date: 2005.01

  • X 線観測とVSOP-2 で切り開く活動銀河核ジェットの物理

     [Invited]

    VSOP2 サイエンスワークショップ 

    Presentation date: 2004.12

  • 大規模ジェットはどこまで理解できたか?電波・X 線観測の総まとめ

    AGN ジェット放射機構と高エネルギー粒子の加速機構 

    Presentation date: 2004.11

  • 宇宙用アバランシェフォトダイオードの開発:衛星搭載と撮像への応用

     [Invited]

    JAXA (つくば) 定例講演会 

    Presentation date: 2004.02

  • 大学規模での衛星開発;東工大の挑戦

     [Invited]

    第4回宇宙科学シンポジウム 

    Presentation date: 2004.01

  • AGN ジェットにおける加速とエネルギー輸送: sub-pc からkpc まで

     [Invited]

    CANGAROO 望遠鏡によるガンマ線天文学の新展開 

    Presentation date: 2003.12

  • Chandra Observation of kpc-Scale Jets: Sites of Extreme Particle Acceleration

     [Invited]

    Japan-Korea Workshop 

    Presentation date: 2003.03

  • X-ray and Gamma-ray Observations of Blazars; Recent Progress and Future Perspectives

     [Invited]

    GLAST collaboration meeting 

    Presentation date: 2002.10

  • 活動銀河ジェットの粒子加速:ブラックホールからホットスポットまで

     [Invited]

    ガンマ線バースト研究会 

    Presentation date: 2002.08

  • 激動する宇宙:X線・ガンマ線天文学最前線

     [Invited]

    高校生のための物理公開講座 

    Presentation date: 2002.07

  • Multiwavelength Observations of Blazars and the Implications on Particle Acceleration in Jets

     [Invited]

    Invited Seminar, Perugia University, Italy 

    Presentation date: 2002.06

  • X-ray Study of Rapid Variability in TeV Blazars and Implications on Particle Acceleration in Jets

     [Invited]

    Presentation date: 2002.03

  • 活動銀河からの高エネルギー放射:観測と理論のアプローチ

     [Invited]

    立教大学理学部セミナー 

    Presentation date: 2001.09

  • 宇宙における巨大加速器:活動銀河核ジェットはどこまで分かったか?

     [Invited]

    2001 天文若手夏の学校 

    Presentation date: 2001.08

  • Characteristic Variability in Blazars: Clues to Jet Physics

     [Invited]

    GLAST collaboration meeting 

    Presentation date: 2001.08

  • 2001 天文若手夏の学校

     [Invited]

    ディスクとジェット研究会 

    Presentation date: 2001.03

  • 活動銀河核からの高エネルギー放射]相対論的ジェットの物理

     [Invited]

    宇宙放射線研究室セミナー 理化学研究所 

    Presentation date: 2001.02

  • TeV ブレーザーの多波長同時観測と時間変動の統一描像

     [Invited]

    ディスクとジェット研究会 

    Presentation date: 2000.03

  • ガンマ線ブレーザーの他波長同時観測と時間変動の統一描像

     [Invited]

    第2回 ぐんま天文台における天体物理学 

    Presentation date: 2000.02

  • X-ray Study of Rapid Variability in TeV Blazars and the Implication on Particle Acceleration in Jets

     [Invited]

    Japan-Germany Symposium 

    Presentation date: 1999.11

▼display all

Research Seeds

Research Projects

  • 細胞から組織、臓器へ:α線治療薬At-211の微視的・巨視的動態イメージング

    日本学術振興会  科学研究費助成事業

    Project Year :

    2024.04
    -
    2027.03
     

    片岡 淳

  • ERATO 片岡ラインX線ガンマ線イメージングプロジェクト

    ERATO

    Project Year :

    2021.10
    -
    2027.03
     

    片岡淳

  • Demonstration of next-generation drug delivery visualization system by integrating treatment and diagnosis

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2020.04
    -
    2023.03
     

  • New-generation medical diagnosis by ultra advancement of X-ray CT

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2019.04
    -
    2023.03
     

  • Innovative gamma-ray imaging based on super-resoluton technique

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2020.07
    -
    2022.03
     

    KATAOKA JUN

     View Summary

    In this study, we developed a new sparse coding technique that can be widely applied to X-ray and gamma-ray images from 10 keV to 10 GeV, and evaluated its performance quantitatively. In the application to space science, we succeeded in sharpening the all-sky map acquired by the Fermi Gamma-ray astronomical satellite and established a new method for automatically detecting transient sources like flaring AGN. In the medical application, we have improved the image quality by sharpening the photon counting CT images. Furthermore, we have developed a new visualization system that can visualize X-rays and gamma rays at the same time. By applying four types of machine learning techniques, we have succeeded in sharpening/improving the images in a short time.

  • Challenges for neutron imaging toward low-dose particle therapy

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2017.06
    -
    2020.03
     

    Kataoka Jun

     View Summary

    The problem of "secondary exposure" is becoming more serious in proton beam therapy for cancer treatment. The proton beam reacts with the metal collimator when it is focused, and it also produces a large amount of fast neutrons in the patient's body. These incidental doses cannot be accurately evaluated by the current treatment system and cannot be reflected in the treatment plan. In this research, we developed an innovative imaging method for fast neutrons, and succeeded in imaging with a proton beam that mimic the actual treatment site. Specifically, we fabricated an array type detector consisting of two layers of waveform discrimination type plastic scintillator, and estimated the neutron arrival direction from the kinematics of elastic scattering. We tried to estimate the dose equivalent using the G(E) function method from the acquired neutron images. We conclude that about 1/100 of the the primary proton dose is given by fast neutrons during the proton therapy.

  • Towards New Fronties in High-resoluton 3-D Color Radiology Imaging

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2015.05
    -
    2020.03
     

    Kataoka Jun

     View Summary

    We developed innovative imaging technologies for X-rays and gamma rays for wide applications to medicine and environmental survey. We constructed a PC-CT system that enables high-speed coloring of each X-ray photons. Multi-color imaging of multiple contrast and anticancer agents was successfully demonstrated under 1/100 dose of conventional CT scan. For gamma rays, we developed the world’s smallest Compton camera that applied for a three-dimensional multicolor imaging of living mice. The camera was further applied to the nuclear medicine treatment to visualize drug delivery for four trial patients. In proton therapy, proton dose was directly imaged by using prompt gamma rays (4.4 MeV) and a novel method of measuring nuclear reactions was proposed. In environmental measurements, we used a commercial drone for rapid 3D visualization of radioactive substances (137Cs) from the sky. We finally developed a super-resolution technology to sharpen the obtained radiation images.

  • 医療応用を目指した3Dカラー放射線イメージングの新展開

    Project Year :

    2015.04
    -
    2019.03
     

  • A Gamma-ray camera to visualize 3-D distribution of radioactive 137-Cs sources

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2015.04
    -
    2017.03
     

    Kataoka Jun

     View Summary

    We developed a novel technique to visualize 3-D distribution of gamma-ray sources, particularly the distribution of 137-Cs which was released from the Fukushima daiichi plant in 2011. We showed that both (1) an event ratio between the full photo-absorption against Compton scattered events, and (2) image blurring due to scattering, can be an excellent estimator of the source localization in the soil, water and concrete. After detailed investigation based on the simulation and table-top experiments, we conducted number of field tests in the forest of Namie, Fukushima. We found that observed spectra can be well fit with a buffer depth beta=2.22+-0.05cm, where we assume distribution of 137-Cs follows as \propto exp(-z/beta). The results is consistent with independent measurements using a scraper prate, confirming the validity of our simple, but non-destructive measurement. We argue that similar approach can be also applicable in the SPECT in which scattered events are usually discarded

  • Development of an innovative PET technique using Geiger-mode APDs for future medical application

    Project Year :

    2010.05
    -
    2015.03
     

     View Summary

    We developed innovative technologies for the next-generation PET scanner utilizing the Multi-Pixel Photon Counters (MPPCs). The key technologies developed here are (i) Depth-Of-Interaction (ii) Magnetic Resonance, and (iii) Time-of-Flight PET imaging techniques. For (i), we invented a novel technique of measuring the 3-D positions of gamma-ray absorption in the scintillators by dual-readout of MPPCs. A virtual 18-ch PET gantry system achieved excellent image resolution of 0.9 mm (FWHM) at the center of FOV, which only slightly degraded to 1.5 mm at the off-center. We also fabricated a compact MRI/PET module designed for small animals that can be used in 4.7 T MRI system. Finally, we designed two front-end ASICs for future PET scanners with Time-Of-Flight (TOF) capability to be coupled with 4×4 MPPC-arrays. We confirmed excellent time resolution of 213 psec for a MPPC pixel, and 489 psec (FWHM) for MPPC-array, as measured using back-to-back 511-keV gamma rays

  • Probing the Origins and Environments of Gamma-Ray Burst with the explosive X-ray and gamma-ray emission

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2007
    -
    2010
     

    KAWAI Nobuyuki, YOSHIDA Atsumasa, YAMAOKA Kazutaka, MURAKAMI Toshio, FUJIMOYO Ryuichi, TOMIDA Hiroshi, KATAOKA Jun

     View Summary

    The goals of this research are quick and precise localization of gamma-ray bursts (GRBs) which lead to prompt observations of afterglows, and investigation of origins and environments of GRBs from detailed X-ray and gamma-ray studies. We developed MAXI and succeeded in detecting and reporting GRBs. We also conducted basic development of X-ray spectrometers and GRB localization instruments. In addition, we analyzed the data obtained by satellites as HETE-2, Fermi, and Suzaku, and studied the correlation between the peak spectral energy and the luminosity, and the energy dependence of the X-ray/gamma-ray light curves

  • Development of high-speed attitude control system for the university satellite in measuring γ-ray polarization of transient sources

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2007
    -
    2009
     

    KATAOKA Jun, MATSUNAGA Saburo, KAWAI Nobuyuki

     View Summary

    We developed an engineering system for a small satellite TSUBMAME, the 4^<th> university satellite of 50kg in mass, developed by the Tokyo Tech. The mission will be an important pathfinder for future space science using the small satellites. We constructed engineering test modules for the hard X-ray Compton polarimeter, wideband burst monitor as well as high-speed attitude control system based on the control momentum gyro. We showed that all the system works pretty well to achieve our science goals for detecting hard X-ray/gamma-ray polarization in various transient sources

  • 小型大学衛星の開発

    Project Year :

    2001
    -
    2009
     

  • Fermi衛星を用いたガンマ線宇宙物理学 (スタンフォード大学他)

    Project Year :

    2008
    -
     
     

  • X-ray Image Reconstruction for Study on Astronomical Cosmic-Ray Acceleration Sites and Development of X-ray Polarimeter

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2006
    -
    2008
     

    KAMAE Tuneyoshi, MAKISHIMA Kazuo, KATAOKA Jun, MIZUNO Tsunefumi

     View Summary

    Images obtained by the Suzaku X-ray mirrors have been deconvolved by a program ; an upper limit to artifact polarization possibly introduced by the hard X-ray mirror has been obtained ; and a new highly sensitive X-ray polarimeter (PoGOLite) has been developed in this Grant-in-Aid in collaboration. The results obtained with the deconvolution program has been published in Sugizaki, Kamae, Okajima, PASJ 61S (2009) 55 ; research and development on PoGOLite in Kamae et al. Astroparticle Phys.30 (2008) 72 ; upper limit to the artifact polarization in Katsuta et al., Nuclear Instr.Meth.A, 603 (2009) 393

  • Development and on-orbit operation of nano-satellite systems enabling to rapidly demonstrate new space technologies

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2004
    -
    2006
     

    MATUNAGA Saburo, NAKASUKA Shinichi, KATAOKA Jun

     View Summary

    In this research, an on-orbit demonstration system of separation mechanism for nano-satellites was successfully conducted on July in 2005 by M-V-8 rocket, and a nano-satellite Cute-1.7 + APD was proposed and developed. The missions include demonstrations of a PDA (personal digital assistant) based onboard computer, attitude control experiment using magnetic torquers, amateur radio service - digital repeater, tether deployment experiment, and APD (avalanched photo diode) sensor demonstration experiment as a scientific mission. Cute-1.7 + APD was launched by the JAXA/ISAS M-V-8 Rocket as a subpayload on February in 2006, and was operated for a month to confirm its fundamental functions. The problems in Cute-1.7+APD are thoroughly investigated in a very short period and the improved follow-on satellite Cute-1.7+APD II was rapidly developed in order to achieve all of the missions. Cute-1.7 + APD II will be launched in 2007 by an Indian rocket PSLV. A pico-satellite XI-V was developed and launched on October in 2005 by a Russian rocket KOSMOS, and was fully operated on-orbit. The missions include demonstrations of CIGS (copper indium gallium di-selenide) thin-film solar cell, precise measurement circuit, improvement of camera control software, and message transmission service. A 5 kg class satellites PRISM was also proposed for remote sensing mission. In particular, development of an extensible boom-based optical system was focused. The development was satisfactorily conducted from BBM phase to EM one, and variable functional tests including radiation test were carried out. The satellites will be launched in summer of 2008 by a H-IIA. The success of these satellites will be good illustrations of the fact that small satellites, especially nano or pico-class satellites provide good opportunities for the demonstration of new space technology in space environment

  • Development of a High Sensitivity PMT assembly for the balloon-borne Soft Gamma-ray Polarimeter

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2004
    -
    2006
     

    KATAOKA Jun, KAWAI Nobuyuki, GUNJI Shuichi, SAITO Yoshitaka

     View Summary

    The Polarized Gamma-ray Observer-Light Version (PoGOLite) is a new balloon-borne experiment designed to measure polarization from astronomical objects, such as pulsars, black holes, and Active Galactic Nuclei, in the 20-100 keV energy range. It is under construction for the first flight expected in 2009. The original purpose for this research was to develop a high sensitivity light sensor (PMT-ASSY) which can be used in the balloon (i.e., low-pressure) environment, and to construct more than 150 units of them for the flight PoGOLite sensors between 2004 and 2006. Now we are happy to report that we have completed our research, with a number of fuits than what we had anticipated. Our results are summarized as follows:(1)Production of more than 150 PMT assembly for the first flight of the PoGOLite.(2)Construction of prototype polarimeter which consisted of 7 phoswich units, and detailed performance test at the synchrotron radiation facility in the KEK photon factory.(3)Development of a "Monte-calro simulator" which enables realistic simulations of PoGOLite sensitivity, under various background events such as cosmic X-ray background (CXB), charged particles, and atmospheric gamma-ray.(4)Detailed test of charged particle response under 400 MeV proton beam at the cyclotron facility in the RCNP, Osaka University(5)Balloon-fight of 1 unit PMT-Assembly as a monitor counter of the PHENEX (Polarimeter for High ENErgy X-rays) experiment in 2006.Through above detailed performance tests, we confirmed that the detector system (PMT-ASSY, and associated electronics, high voltage etc) developed in this research works pretty well under serious conditions expected in balloon orbit. In particular, we showed that the PMT-ASSY monitors count rate of signal/background events for 16 hours in the PHENEX experiments. Dramatically, the count rate of the monitor counter increased significantly when the Crab-nebular/pulsar was locked in the detector field of view

  • Measurement of size of super massive black holes through observation of X-ray variabilities

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2002
    -
    2004
     

    HAYASHIDA Kiyoshi, INOUE Hajime, AWAKI Hisamitsu, NEGORO Hitoshi, KATAOKA Jun

     View Summary

    This research project is aimed to study X-ray variability of Active Galactic Nuclei (AGN) in order to estimate their fundamental properties, such as masses of black holes residing them. We also study physical mechanism to generate radiation from AGNs through X-ray variability and spectra. Our targets range from low luminosity AGNs, Seyfert type 1 and type 2, radio galaxies, and blazers.1. We proposed to use the power spectra of X-ray variability as a measure of black hole size, namely black hole mass. We originally applied this scheme to bright Seyfert 1 galaxies, but extend it to various types of AGNs, including the lowest luminosity Seyfert 1 galaxy NGC4395, Seyfert 2 galaxies, NGC6300. In these cases, the power spectral shape is similar to that for bright Seyfert 1 galaxies and stellar mass black holes, indicating commmon mechanism is working in these accreting black holes. Black hole mass of NGC4395 is estimated to be tens of thousand Solar mass, which is intermediate between stellar mass black holes and super massive black holes and important for models for black hole evolution.2.Variabilities in X-ray intensity and spectra were studied in detail in several sources, including Ark564, MCG-6-30-15, and many blazers. Iron emission line is usually interpreted as a fluorescent line from the vicinity of a black hole, but alternative models proposed for MCG-6-30-15. X-ray and other wave length data on variabilities of blazers indicate physical mechanism occurred in jet from these sources. We show internal shock is important to explain the spectral evolution of some of the flares in blazers.3.We thick we can use X-ray variability as a tool to estimate black hole size, but the origin and physical mechanism that makes the variability is still unclear. That will be the next step for our study

  • 半導体増幅素子APD,MPPCを用いた放射線検出器の開発 (JST、NEDO、浜松ホトニクスほか)

    Project Year :

    2003
    -
     
     

  • 新開発の大口径空気チェレンコフ望遠鏡を用いた活動銀河核からのTeVγ線放射の研究

    日本学術振興会  科学研究費助成事業

    Project Year :

    2000
     
     
     

    片岡 淳

  • 活動銀河核ジェットの観測的研究

    Project Year :

    1995
    -
     
     

  • 衛星搭載用 宇宙X線・ガンマ線検出器の開発 (JAXAほか)

    Project Year :

    1995
    -
     
     

  • ガンマ線バースト即時観測用ロボット望遠鏡システムの開発

     View Summary

    本研究の目的は、HETE-2およびSwift衛星からインターネットを通じて配信されるガンマ線バースト速報に対応して、自動的に即時にバーストの方向を撮像する望遠鏡システムを開発し、ガンマ線バーストに伴う可視光フラッシュの観測を行なうことである。本年度は、次の作業を行なった。1.別予算にて岡山県美星天文台屋上に設置した口径30cm望遠鏡の測光精度を調査した。Landolt測光標準星との比較によれば、本システムはフィルター無しにもかかわらず、Rバンドでは標準星のカタログ等級と0.1等以下の誤差でよい比例関係をもつことを確かめた。2.昨年度に製作して宮崎大学工学部の屋上に設置したロボット望遠鏡システム第二号機の調整、試験を行い、指向・追尾性能試験および撮像試験を行った。試験観測として、美星天文台に設置した一号機とともに、変光星、獅子座流星群、超新星2002apなどの観測を行った。3.ロボット望遠鏡システムを統括制御するソフトウェアを改良し、自動観測運用を開始した。雨あるいは雪による機械的、あるいは電気的な不具合が生じたので、修理・対策を施した。4.HETE-2およびBeppoSAX衛星が検出したガンマ線バースト4個(GRB010921, GRB011019, GRB011030, GRB020124)に対して追観測を行った。可視対応天体の検出には至っていない

  • 次世代データ処理を目指した、全天X線モニター地上試験システムの開発

     View Summary

    全天X線モニター(MAXI)は、2008年度に国際宇宙ステーション(ISS)日本モジュールに搭載される予定のX線検出器であり、現在試作モデルとフライト検出器の製作が行われている。本年は、MAXIプロジェクトの存続を決める上で最も重要な年で、CDR (Critical Design Review)をはじめとして搭載システムの詳細な検討が行われた。特にデジタルプロセッサー部分については、Release-2と呼ばれる試作モデルの性能評価を行ったが、地上試験でも機上と全く同じアナログ処理部を再現する必要があり、本研究で開発した「地上試験システム」が用いられた。昨年度は、同じシステムを全く逆の用途、つまり、アナログ処理部の詳細試験を行うための"擬似デジタルプロセッサー"として用いたが、本年度の試験を通じて申請の目的をすべて達成したことになる。ハードウェアとしては、昨年度製作したVME処理ボードを用いて、家庭用パソコン(CPU1GHz、メモリ512Mbyte)に接続して試験を行った。FPGAのプログラミングも全て終了し、本システムは現在、理化学研究所(宇宙放射線研究室)およびJAXA(宇宙環境計測システム)に常備され、様々な試験に役立てている。昨年度の実績とあわせ、本年度の開発の概要、開発したシステムについては8月の国際学会(SPIE)で口頭発表を行った。結果はSPIE学術誌2003,vol5165,375-386にkataoka et al.として掲載されている。発表においては多くの質問や活発な議論が行われ、改めてこの分野に対する研究者め関心の高さを実感した

  • MPPC光増幅素子を用いた革新的分子イメージング技術の開拓

▼display all

Misc

  • 薬物動態を可視化する放射化イメージング:宇宙の元素合成を医療に応用

    越川七星, 片岡淳

    月刊化学   78 ( 5 ) 33 - 37  2023.04  [Invited]

    Authorship:Last author

  • Simultaneous imaging of prompt gamma photons and prompt X-rays during irradiation of proton beams

    山本誠一, 山下智弘, 小橋佑介, 矢部卓也, 山口充孝, 河地有木, 鎌田圭, 吉川彰, 赤城卓, 片岡淳

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   70th  2023

    J-GLOBAL

  • 広帯域X線・ガンマ線による薬剤可視化へ向けた新技術

    越川七星, 増渕美穂, 片岡淳

    応用物理学会・放射線分科会会誌   48 ( 1 ) 14 - 22  2023.01  [Invited]

  • Demonstration of Visualization of Drugs Using Radioactivation

    越川七星, 増渕美穂, 片岡淳, 床井健運, 中川創太, 今田彩香, 松永恵子, 加藤弘樹, 角永悠一郎, 豊嶋厚史, 高宮幸一, 上田真史

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   83rd  2022

    J-GLOBAL

  • CT Development at the Front Line: Photon-Counting CT

    有元誠, 川嶋広貴, 小林聡, 片岡淳

    日獨医報   66 ( 1 )  2022  [Invited]

    J-GLOBAL

  • コンプトンカメラを用いたアクティブ動態イメージング

    片岡淳, 小俣陽久, 増渕美穂, 越川七星

       2021.12  [Invited]

  • Spectral Photon-counting CT System based on Si-PM coupled with Novel Ceramic Scintillators

    Radiation Detection Systems - Medical Imaging, Industrial Testing and Security Applications (CRC press)    2021.04  [Invited]

  • Development and demonstration of new imaging methods using wide-band X ray and gamma ray

    増渕美穂, 小俣陽久, 越川七星, 片岡淳, 加藤弘樹, 豊嶋厚史, 寺本高啓, 松永恵子, 神谷貴史, 渡部直史, 下瀬川恵久, 畑澤順, 上ノ町水紀

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   82nd  2021

    J-GLOBAL

  • Suggestion of novel radioactive imaging method with wide-band X ray and gamma ray: 2

    小俣陽久, 増渕美穂, 越川七星, 岡崎優, 片岡淳, 松永恵子, 加藤弘樹

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   82nd  2021

    J-GLOBAL

  • Suggestion of novel radioactive imaging method with wide-band X ray and gamma ray: 1

    越川七星, 小俣陽久, 増渕美穂, 岡崎優, 片岡淳, 松永恵子, 加藤弘樹

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   82nd  2021

    J-GLOBAL

  • CTA Report 172: General Report

    窪秀利, 手嶋政廣, 手嶋政廣, 戸谷友則, 浅野勝晃, 阿部日向, 阿部正太郎, 粟井恭輔, 井岡邦仁, 石尾一馬, 石尾一馬, 石崎渉, 稲田知大, 井上進, 井上剛志, 井上芳幸, 猪目祐介, 今澤遼, 岩村由樹, WARREN Donald, 内山泰伸, 大石理子, OWEN Ellis R., 大岡秀行, 大谷恵生, 大平豊, 岡知彦, 岡崎奈緒, 奥村曉, 奥村曉, 小原光太郎, 折戸玲子, 加賀谷美佳, 片岡淳, 片桐秀明, 勝田哲, KHALIKOV Emil, 川島翔太郎, 川中宣太, 川村孔明, 木坂将大, CUI Xiaohong, 櫛田淳子, 黒田裕介, 郡司修一, 郡和範, 小林志鳳, KONG Albert K. H., 齋藤隆之, 榊直人, 櫻井駿介, 佐々木寅旭, 佐々木陽香, 佐藤優理, 佐野栄俊, 澤田真理, 柴田徹, DZHATDOEV Timur, 鈴木寛大, 須田祐介, 須田祐介, STRZYS Marcel, STRZYS Marcel, 砂田裕志, ZENIN Anatolii, 高田順平, 高橋満里, 高橋慶太郎, 高橋弘充, 高橋光成, 武石隆治, 田島宏康, 立原研悟, 立石大, 田中周太, 田中孝明, 田中真伸, TAM Thomas P.H., CHENG K.S., 千川道幸, 塚本友祐, 鶴剛, TIAN Wenwu, 寺内健太, 寺田幸功, 當真賢二, 門叶冬樹, 内藤統也, 長瀧重博, 中森健之, 中山和則, 生天目康之, 西嶋恭司, 野上優人, 野崎誠也, 野田浩司, 野村亮介, BARKOV Maxim, 芳賀純也, バクスタージョシュア稜, 橋山和明, HADASCH Daniela, 早川貴敬, 林克洋, 林航平, 林田将明, 原敏, 原田善規, 馬場彩, 平松明秀, 廣島渚, 広谷幸一, HUI David C.Y., FERRAND Gilles, 深沢泰司, 深見哲志, 福井康雄, 藤川由衣, 藤田裕, HE Haoning

    日本物理学会講演概要集(CD-ROM)   76 ( 1 ) 556 - 556  2021

    DOI J-GLOBAL

  • Activity bubbling up

    Jun Kataoka

    Nature Astronomy   5 ( 1 ) 11 - 12  2021.01

    Rapid communication, short report, research note, etc. (scientific journal)  

    DOI

  • Four types of machine learning analysis for Compton camera image

    佐藤将吾, 片岡淳, 古徳純一, 瀧雅人, 大山飛鳥, 田川怜央, 藤枝和也, 西郁也, 豊田貴也

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   67th  2020

    J-GLOBAL

  • Novel photon-counting CT using MPPCs and fast scintillators

    Makoto Arimoto, Jun Kataoka, Shinsuke Terazawa, Satoshi Shiota

    Hitachi Metals Technical Review   36   28 - 33  2020.01  [Invited]

    Internal/External technical report, pre-print, etc.  

  • The CALorimetric Electron Telescope (CALET) on the international space station: Results from the first two years on orbit

    Y. Asaoka, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, A. Bruno, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, V. Pal'Shin, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Journal of Physics: Conference Series   1181 ( 1 )  2019.03  [Refereed]

     View Summary

    © Published under licence by IOP Publishing Ltd. The CALorimetric Electron Telescope (CALET) is a high-energy astroparticle physics space experiment installed on the International Space Station (ISS), developed and operated by Japan in collaboration with Italy and the United States. The CALET mission goals include the investigation of possible nearby sources of high-energy electrons, of the details of galactic particle acceleration and propagation, and of potential signatures of dark matter. CALET measures the cosmic-ray electron+positron flux up to 20 TeV, gamma-rays up to 10 TeV, and nuclei with Z=1 to 40 up to 1, 000 TeV for the more abundant elements during a long-term observation aboard the ISS. Starting science operation in mid-October 2015, CALET performed continuous observation without major interruption with close to 20 million triggered events over 10 GeV per month. Based on the data taken during the first two-years, we present an overview of CALET observations: 1) Electron+positron energy spectrum, 2) Nuclei analysis, 3) Gamma-ray observation including a characterization of on-orbit performance. Results of the electromagnetic counterpart search for LIGO/Virgo gravitational wave events are discussed as well.

    DOI

  • CTA Project 155: Status Report

    Teshima Masahiro, Kubo Hidetoshi, Totani Tomonori, Asano Katsuaki, Ioka Kunihito, Ishio Kazuma, Inada Tomohiro, Inoue Susumu, Inoue Tsuyoshi, Inoue Yoshiyuki, Inome Yusuke, Iwamura Yuki, Warren Donald, Uchiyama Yasunobu, Ohishi Michiko, Ohoka Hideyuki, Ohtani Yoshiki, Ohira Yutaka, Oka Tomohiko, Okazaki Nao, Ogata Tomoyuki, Okumura Akira, Orito Reiko, Kagaya Mika, Kajiwara Yuki, Kataoka Jun, Katagiri Hideaki, Katsukura Daisuke, Katsuda Satoru, Khalikov Emil, Kawanaka Norita, Kisaka Shota, Cui Xiaohong, Kushida Junko, Gunji Shuichi, Kohri Kazunori, Kobayashi Yukiho, Kong Albert K. H., Saito Takayuki, Sakaki Naoto, Sakurai Shunsuke, Sano Hidetoshi, Sawada Makoto, Shibata Toru, Dzhatdoev Timur, Suzuki Megumi, Suzuki Hiromasa, Suda Yusuke, Sunada Yuji, Zenin Anatolii, Takata Jumpei, Takahashi Keitaro, Takahashi Hiromitsu, Takahashi Mitsunari, Tajima Hiroyasu, Tachihara Kengo, Tanaka Shuta, Tanaka Takaaki, Tanaka Manobu, Tam Thomas P. H., Tamura Kenji, Cheng K. S., Chikawa Michiyuki, Choushi Yuuki, Tsujimoto Shimpei, Tsuru Takeshi, Tian Wenwu, Terada Yukikatsu, Toma Kenji, Tokanai Fuyuki, Naito Tsuguya, Nagataki Shigehiro, Nakamura Yuki, Nakamori Takeshi, Nakayama Kazunori, Nishijima Kyoshi, Nozaki Seiya, Noda Koji, Barkov Maxim, Hadasch Daniela, Hayakawa Takahiro, Hayashi Katsuhiro, Hayashida Masaaki, Hara Satoshi, Bamba Aya, Hidaka Naoya, Hiroshima Nagisa, Hirotani Kouichi, Hui David C. Y., Ferrand Gilles, Fukazawa Yasushi, Fukami Satoshi, Fukui Yasuo, Fujita Yutaka, Fujihara Chikako, Furuta Tomoya, He Haoning, Majumdar Pratik, Mazin Daniel, Matsumoto Hironori, Mizuno Tsunefumi, Muraish Hiroshi, Murase Kohta, Mori Koji, Yanagita Shohei, Yamazaki Ryo, Yamane Yumiko, Yamamoto Tokonatsu, Yamamoto Hiroaki, Yoshikoshi Takanori, Yoshida Atsumasa, Yoshida Tatsuo, Lee Shiu-Hang (Herman)

    Meeting Abstracts of the Physical Society of Japan   74.2   358 - 358  2019

    DOI CiNii

  • HITOMI (ASTRO-H) X-ray astronomy satellite

    Tadayuki Takahashi, Motohide Kokubun, Kazuhisa Mitsuda, Richard L. Kelley, Takaya Ohashi, Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Makoto Asai, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Philipp Azzarello, Chris Baluta, Aya Bamba, Nobutaka Bando, Marshall W. Bautz, Thomas Bialas, Roger Blandford, Kevin Boyce, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Edgar Canavan, Maria Chernyakova, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Steve O' Dell, Michael DiPirro, Chris Done, Tadayasu Dotani, John Doty, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Stefan Funk, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Kirk Gilmore, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Daniel Haas, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Takayuki Hayashi, Katsuhiro Hayashi, Kiyoshi Hayashida, Jan Willem Den Herder, Junko S. Hiraga, Kazuyuki Hirose, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Kazunori Ishibashi, Manabu Ishida, Kumi Ishikawa, Kosei Ishimura, Yoshitaka Ishisaki, Masayuki Itoh, Masachika Iwai, Naoko Iwata, Naoko Iyomoto, Chris Jewell, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Erin Kara, Jun Kataoka, Satoru Katsuda, Junichiro Katsuta, Madoka Kawaharada, Nobuyuki Kawai, Taro Kawano, Shigeo Kawasaki, Dmitry Khangulyan, Caroline A. Kilbourne, Mark Kimball

    Journal of Astronomical Telescopes, Instruments, and Systems   4 ( 2 )  2018.04

    Book review, literature introduction, etc.  

     View Summary

    The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

    DOI

  • 「ひとみ」HXIを用いた軌道上中性子バックグラウンドの評価

    鈴木寛大, 中澤知洋, 萩野浩一, 国分紀秀, 佐藤悟朗, 高橋忠幸, 渡辺伸, 太田方之, 佐藤理江, 森國城, 村上浩章, 三宅克馬, 古田禄大, 馬場彩, 鶴剛, 田中孝明, 榎戸輝揚, 小林翔悟, 寺田幸功, 内山秀樹, 谷津洋一, 野田博文, 田島宏康, 山岡和貴, 林克洋, 林克洋, 深沢泰司, 水野恒史, 大野雅功, 高橋弘充, 勝田隼一郎, 中森健之, 内山泰伸, 斉藤新也, 牧島一夫, 小高裕和, 湯浅孝行, 中野俊男, 片岡淳, 三村健人, LEBRUN Francois, LIMOUSIN Olivier, LAURENT Philippe, MAIER Daniel, 武田伸一郎, 森浩二

    日本天文学会年会講演予稿集   2018   227  2018.02

    J-GLOBAL

  • 増幅型光センサーMPPCを用いた低被ばく・多色CTへの挑戦

    有元誠, 片岡淳

    Isotope News (Web)   ( 755 ) 25‐29 (WEB ONLY)  2018.02  [Invited]

    Article, review, commentary, editorial, etc. (scientific journal)  

    J-GLOBAL

  • CTA報告139:全体報告

    窪 秀利, 井上 剛志, 深見 哲志, 福井 康雄, 藤田 裕, 藤原 千賀己, He Haoning, Majumdar Pratik, Mazin Daniel, 増田 周, 松本 浩典, 三浦 智佳, 井上 芳幸, 水野 恒史, 村石 浩, 村瀬 孔大, 森 浩二, 柳田 昭平, 山崎 了, 山本 常夏, 山本 宏昭, 吉池 智史, 吉越 貴紀, 猪目 祐介, 吉田 篤正, 吉田 龍生, 李 健, 李 兆衡, 岩村 由樹, Warren Donald, 内山 泰伸, 大石 理子, 大岡 秀行, 大平 豊, 岡崎 奈緒, 手嶋 政廣, 奥村 曉, 折戸 玲子, 加賀谷 美佳, 格和 純, 片岡 淳, 片桐 秀明, 勝倉 大輔, 勝田 哲, 加藤 翔, 神本 匠, 戸谷 友則, 川中 宣太, 木坂 将大, 木村 颯一朗, Cui Xiaohong, 櫛田 淳子, 久門 拓, 黒田 隼人, 郡司 修一, 郡 和範, 小山 志勇, 朝野 彰, Kong Albert K. H, 齋藤 隆之, 榊 直人, 櫻井 駿介, 佐々井 義矩, 佐野 栄俊, 澤田 真理, 柴田 徹, Dzhatdoev Timur, 鈴木 萌, 浅野 勝晃, 砂田 裕志, 関崎 晴仁, Zenin Anatolii, 高田 順平, 高橋 慶太郎, 高橋 知也, 高橋 弘充, 高橋 光成, 髙原 大, 田島 宏康, 井岡 邦仁, 立原 研悟, 田中 周太, 田中 孝明, 田中 真伸, 田中 康之, 種田 裕貴, Tam Thomas P. H, Cheng K. S, 千川 道幸, 辻本 晋平, 石尾 一馬, 鶴 剛, Tian Wenwu, 寺田 幸功, 當真 賢二, 門叶 冬樹, 内藤 統也, 中嶋 大輔, 長瀧 重博, 中村 裕樹, 中森 健之, 稲田 知大, 中山 和則, 永吉 勤, 西嶋 恭司, 西山 楽, 野崎 誠也, 野田 浩司, Barkov Maxim, Hadasch Daniela, 早川 貴敬, 林 克洋, 井上 進, 林田 将明, 原 敏, 馬場 彩, 日高 直哉, 平子 丈, 廣島 渚, 広谷 幸一, Hui David, C. Y, Ferrand Gilles, 深沢 泰司

    日本物理学会講演概要集   73 ( 0 ) 188 - 188  2018

    DOI CiNii J-GLOBAL

  • CTA Project 130: General Report

    Teshima Masahiro, Kubo Hidetoshi, Totani Tomonori, Consortium for, the CTA-Japan

    Meeting Abstracts of the Physical Society of Japan   73 ( 0 ) 412-412 - 412  2018

    DOI CiNii

  • Development of Innovative Proton CT System for High-Precise Proton Therapy

    有元誠, 高部美穂, 増田孝充, 片岡淳, 羽鳥聡, 久米恭, 長谷川崇

    若狭湾エネルギー研究センター研究年報   19   45‐47  2017.10

    Internal/External technical report, pre-print, etc.  

    J-GLOBAL

  • 森林除染に向けたドローン活用事例:里山における空間線量率の鉛直観測とドローン搭載ガンマ線カメラによる迅速調査への活用

    大河内博, 片岡淳, 岸本彩, 岩本康弘, 金野俊太郎, 黒島碩人, 勝見尚也, 緒方裕子, 反町篤行, 床次眞司

    大気環境学会年会講演要旨集   58th   140‐142  2017.08

    J-GLOBAL

  • CTA Project 117: General Report

    Teshima Masahiro, Kubo Hidetoshi, Totani Tomonori, Asano Akira, Asano Katsuaki, Ioka Kunihito, Ikeno Yuhei, Ishio Kazuma, Inada Tomohiro, Inoue Susumu, Inoue Tsuyoshi, Inoue Yoshiyuki, Inome Yusuke, Iwamura Yuki, Warren Donald, Uchiyama Yasunobu, Umetsu Yohei, Ohishi Michiko, Ohoka Hideyuki, Ohira Yutaka, Okazaki Nao, Okumura Akira, Orito Reiko, Kagaya Mika, Kakuwa Jun, Kataoka Jun, Katagiri Hideaki, Kato Sho, Kawanaka Norita, Kisaka Shota, Kishida Shu, Kimura Souichiro, Cui Xiaohong, Kushida Junko, Kuroda Hayato, Gunji Shuichi, Kohri Kazunori, Koyama Shu, Kong Albert K. H., Konno Yusuke, Saito Takayuki, Sakaki Naoto, Sakurai Shunsuke, Sato Yuta, Sano Hidetoshi, Sawada Makoto, Shigenaka Akane, Shibata Toru, Takata Jumpei, Takahashi Keitaro, Takahashi Hiromitsu, Takahashi Mitsunari, Takami Shota, Takeda Junki, Tajima Hiroyasu, Tachihara Kengo, Tanaka Shuta, Tanaka Takaaki, Tanaka Manobu, Tanaka Yasuyuki, Tanigawa Shunsuke, Tam Thomas P. H., Tan Dang Viet, Cheng K. S., Chikawa Michiyuki, Tsujimoto Shimpei, Tsuru Takeshi, Tian Wenwu, Terada Yukikatsu, Toma Kenji, Tokanai Fuyuki, Tomono Yayoi, Naito Tsuguya, Nakajima Daisuke, Nagataki Shigehiro, Nakamura Yuki, Nakamori Takeshi, Nakayama Kazunori, Nagayoshi Tsutomu, Nishijima Kyoshi, Nishiyama Gaku, Nozaki Seiya, Noda Koji, Barkov Maxim, Hadasch Daniela, Hayakawa Takahiro, Hayashi Katsuhiro, Hayashida Masaaki, Hara Satoshi, Bamba Aya, Hidaka Naoya, Hirai Wataru, Hiroshima Nagisa, Hirotani Kouichi, Hui David C. Y., Ferrand Gilles, Fukazawa Yasushi, Fukami Satoshi, Fukui Yasuo, Fujita Yutaka, He Haoning, Majumdar Pratik, Mazin Daniel, Masuda Shu, Matsumoto Hironori, Mizuno Tsunefumi, Muraishi Hiroshi, Murase Kohta, Motohashi Daisuke, Mori Koji, Yanagita Shohei, Yamazaki Ryo, Yamane Nobuhito, Yamamoto Tokonatsu, Yamamoto Hiroaki, Yoshiike Satoshi, Yoshikoshi Takanori, Yoshida Atsumasa, Yoshida Tatsuo, Yoshida Mayu, Lee Shiu-Hang (Herman)

    Meeting Abstracts of the Physical Society of Japan   72.1   457 - 457  2017

    DOI CiNii

  • 粒子線治療オンラインモニタに向けたコンプトンカメラ画像再構成の最適化と実機検証

    多屋隆紀, 片岡淳, 岸本彩, 田川怜央, 望月早駆, 歳藤利行, 木村充宏, 河地有木, 山口充孝, 長尾悠人, 栗田圭輔

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   64th  2017

    J-GLOBAL

  • 医療用コンプトンカメラによる3次元小動物イメージング

    岸本彩, 片岡淳, 田川怜央, 望月早駆, 多屋隆紀, 大須賀慎二, 松永恵子, 池田隼人, 下瀬川恵久, 畑澤順, 河地有木, 長尾悠人, 山口充孝, 栗田圭輔

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   64th  2017

    J-GLOBAL

  • In-orbit performance of the hard X-ray and soft gamma-ray instruments onboard Hitomi

       2017.01

     View Summary

    17th Space Science Symposium (January 5-6, 2017. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

    CiNii

  • 福島県の里山に大気沈着した放射性セシウムの長期変動

    金野俊太郎, 大河内博, 黒島碩人, 勝見尚也, 緒方裕子, 片岡淳, 岸本彩, 岩本康弘, 反町篤行, 床次眞司

    日本地球惑星科学連合大会予稿集(Web)   2017   ROMBUNNO.MAG34‐P03 (WEB ONLY)  2017

    J-GLOBAL

  • ひとみ(ASTRO‐H)衛星搭載硬X線軟ガンマ線検出器BGOアクティブシールドの軌道上性能

    大野雅功, 深沢泰司, 水野恒史, 高橋弘充, 北口貴雄, 田中康之, 勝田隼一郎, 河野貴文, 白川裕章, 枝廣育実, 幅田翔, 岡田千穂, 大橋礼恵, 田中晃司, 高橋忠幸, 国分紀秀, 渡辺伸, 佐藤悟朗, 太田方之, 萩野浩一, 佐藤理江, 森國城, 内田悠介, 桂川美穂, 都丸亮太, 米田浩基, 中澤知洋, 鳥井俊輔, 桜井壮希, 笹野理, 西田瑛量, 小林翔悟, 村上浩章, 小野光, 加藤佑一, 三宅克馬, 古田禄大, 室田優紀, 田島宏康, 木下将臣, 山岡和貴, 林克洋, 林克洋, 片岡淳, 斎藤龍彦, 吉野将生, 三村健人, 谷津陽一, 斉藤新也, 内山秀樹, 中森健之, 武田伸一郎, 中野俊男, 一戸悠人

    日本物理学会講演概要集(CD-ROM)   71 ( 2 ) ROMBUNNO.24aSP‐8 - 372  2016.09

    DOI CiNii J-GLOBAL

  • 里山に大気沈着した放射性Csの動態と環境調和型除染技術の開発(2)

    金野俊太郎, 大河内博, 緒方裕子, 勝見尚也, 反町篤行, 床次眞司, 片岡淳, 岸本彩

    大気環境学会年会講演要旨集   57th   250  2016.08

    J-GLOBAL

  • X線天文衛星「ひとみ(ASTRO‐H)」搭載硬X線撮像検出器(HXI)の軌道上動作

    萩野浩一, 中澤知洋, 国分紀秀, 佐藤悟朗, 高橋忠幸, 渡辺伸, 太田方之, 佐藤理江, LEE Herman, 能町正治, 米徳大輔, 田中孝明, 榎戸輝揚, 寺田幸功, 内山秀樹, 谷津洋一, 一戸悠人, 野田博文, 田島宏康, 山岡和貴, 林克洋, 林克洋, 深沢泰司, 水野恒史, 大野雅功, 高橋弘充, 中森健之, 内山泰伸, 斉藤新也, 牧島一夫, 湯浅孝行, 中野俊男, 片岡淳, LEBRUN Francois, GOLDWURM Andrea, LIMOUSIN Olivier, LAURENT Philippe, MAIER Daniel, 武田伸一郎, 小高裕和

    日本天文学会年会講演予稿集   2016   245  2016.08

    J-GLOBAL

  • 「ひとみ(ASTRO‐H)」搭載SGDのBGOシールドを用いたガンマ線バースト位置決定能力の評価

    田中晃司, 大野雅功, 深沢泰司, 水野恒史, 高橋弘充, 北口貴雄, 田中康之, 勝田隼一郎, 河野貴文, 白川裕章, 枝廣育実, 幅田翔, 岡田千穂, 大橋礼恵, 高橋忠幸, 国分紀秀, 渡辺伸, 佐藤悟朗, 太田方之, 萩野浩一, 佐藤理江, 森國城, 内田悠介, 桂川美穂, 都丸亮太, 米田浩基, 中澤知洋, 鳥井俊輔, 桜井壮希, 笹野理, 西田瑛量, 小林翔悟, 村上浩章, 小野光, 加藤佑一, 三宅寛馬, 古田禄大, 室田優紀, 田島宏康, 木下将臣, 山岡和貴, 林克洋, 林克洋, 片岡淳, 斎藤龍彦, 吉野将生, 三村健人, 谷津陽一, 斉藤新也, 内山秀樹, 中森健之, 武田伸一郎, 中野俊男, 一戸悠人

    日本天文学会年会講演予稿集   2016   246  2016.08

    J-GLOBAL

  • 「ひとみ(ASTRO‐H)」搭載硬X線軟ガンマ線検出器におけるBGOアクティブシールドの軌道上性能

    大野雅功, 深沢泰司, 水野恒史, 高橋弘充, 北口貴雄, 田中康之, 勝田隼一郎, 河野貴文, 白川裕章, 枝廣育実, 幅田翔, 岡田千穂, 大橋礼恵, 田中晃司, 高橋忠幸, 国分紀秀, 渡辺伸, 佐藤悟朗, 太田方之, 萩野浩一, 佐藤理江, 森國城, 内田悠介, 桂川美穂, 都丸亮太, 米田浩基, 中澤知洋, 鳥井俊輔, 桜井壮希, 笹野理, 西田瑛量, 小林翔悟, 村上浩章, 小野光, 加藤佑一, 三宅克馬, 古田禄大, 室田優紀, 田島宏康, 木下将臣, 山岡和貴, 林克洋, 林克洋, 片岡淳, 斎藤龍彦, 吉野将生, 三村健人, 谷津陽一, 斉藤新也, 内山秀樹, 中森健之, 武田伸一郎, 中野俊男, 一戸悠人

    日本天文学会年会講演予稿集   2016   245  2016.08

    J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮像検出器(HXI)の現状打ち上げ

    中澤知洋, 国分紀秀, 佐藤悟朗, 萩野浩一, 太田方之, 小高裕和, 川原田円, 佐藤理江, 高橋忠幸, 武田伸一郎, 原山淳, 渡辺伸, 榎戸輝揚, 田中孝明, 寺田幸功, 内山秀樹, 谷津陽一, 中野俊男, 田島宏康, 山岡和貴, 大野雅功, 勝田隼一郎, 高橋弘充, 深沢泰司, 水野恒史, 中森健之, 野田博文, 牧島一夫, 湯浅孝行, 内山泰伸, 斉藤新也, 片岡淳, LAURENT Philippe, LEBRUN Francois, LIMOUSIN Okivier

    日本天文学会年会講演予稿集   2016   211  2016.02

    J-GLOBAL

  • ASTRO‐H搭載硬X線撮像検出器(HXI)の地上試験における最終性能

    小林翔悟, 佐藤悟朗, 萩野浩一, 中野俊男, 中澤知洋, 湯浅孝行, 牧島一夫, 榎戸輝揚, 佐藤理江, 渡辺伸, 国分紀秀, 高橋忠幸, 斉藤新也, 内山泰伸, 片岡淳, 谷津陽一, 北口貴雄, 大野雅功, 高橋弘充, 水野恒史, 深沢泰司, 田島宏康, 寺田幸功, 中森健之, LIMOUSIN Olivier, LAURENT Philippe, LEBRUN Francois

    日本物理学会講演概要集(CD-ROM)   70 ( 2 ) ROMBUNNO.25PSJ-4 - 352  2015.09

    DOI CiNii J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮像検出器(HXI)の現状打上げに向けて

    中澤知洋, 国分紀秀, 佐藤悟朗, 萩野浩一, 太田方之, 小高裕和, 川原田円, 佐藤理江, 高橋忠幸, 武田伸一郎, 原山淳, 渡辺伸, 榎戸輝揚, 田中孝明, 寺田幸功, 内山秀樹, 谷津陽一, 中野俊男, 牧島一夫, 田島宏康, 山岡和貴, 大野雅功, 勝田隼一郎, 高橋弘充, 深沢泰司, 水野恒史, 中森健之, 野田博文, 湯浅孝行, 内山泰伸, 斉藤新也, 片岡淳, LAURENT Philippe, LEBRUN Francois, LIMOUSIN Olivier

    日本天文学会年会講演予稿集   2015   255  2015.08

    J-GLOBAL

  • 福島県の里山に大気沈着した放射性セシウムの動態解明と環境調和型除染技術の開発(1)

    金野俊太郎, 大河内博, 黒島碩人, 緒方裕子, 反町篤行, 床次眞司, 細田正洋, 片岡淳, 岸本彩

    環境化学討論会要旨集(CD-ROM)   24th   ROMBUNNO.P‐174  2015.06

    J-GLOBAL

  • Recent progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging

    J. Kataoka, A. Kishimoto, T. Fujita, T. Nishiyama, Y. Kurei, T. Tsujikawa, T. Oshima, T. Taya, Y. Iwamoto, H. Ogata, H. Okochi, S. Ohsuka, H. Ikeda, S. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   784   248 - 254  2015.06

     View Summary

    The multi-pixel photon counter (MPPC) is a promising light sensor for various applications, not only in physics experiments but also in nuclear medicine, industry, and even high-energy astrophysics. In this paper, we present the current status and most recent progress of the MPPC-based scintillation detectors, such as (1) a high-precision X-ray and gamma-ray spectral image sensor, (2) next-generation PET detectors with MRI, TOF, and DOI measurement capabilities, and (3) a compact gamma camera for environmental radiation surveys. We first present a new method of fabricating a Ce:GAGG scintillator plate (1 or 2 mm thick) with ultra-fine resolution (0.2 mm/pixel), cut using a dicing saw to create 50 mu m wide micro-grooves. When the plate is optically coupled with a large-area MPPC array, excellent spatial resolution of 0.48 mm (FWHM) and energy resolution of 14% (FWHM) are obtained for 122 keV gamma rays. Hence, the detector can act as a convenient "multi-color" imaging device that can potentially be used for future SPECT and photon-counting CT. We then show a prototype system for a high-resolution MPPC-based PET scanner that can realize similar or equal to 1 mm (FWHM) spatial resolution, even under a strong magnetic field of 4.7 T. We develop a front-end ASIC intended for future TOF-PET scanner with a 16-channel readout that achieves a coincidence time resolution of 489 ps (FWHM). A novel design for a module with DOI-measurement capability for gamma rays is also presented by measuring the pulse height ratio of double-sided MPPCs coupled at both ends of scintillation crystal block. Finally, we present the concept of a two-plane Compton camera consisting of Ce:GAGG scintillator arrays coupled with thin MPPC arrays. As a result of the thin and compact features of the MPPC device, the camera not only achieves a small size (14 x 14 x 15 cm(3)) and light weight (1.9 kg) but also excellent sensitivity, compared to the conventional PMT-based pinhole camera used in Fukushima. Finally, we briefly describe a new product recently developed in conjunction with Hamamatsu Photonics K.K. that offers improved sensitivity and angular resolution of Delta theta similar to 8 degrees (FWHM) at 662 key, by incorporating DOI-segmented scintillator arrays. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • ASTRO‐H衛星搭載硬X線軟ガンマ線検出器におけるBGOアクティブシールドの地上較正試験

    大野雅功, 河野貴文, 古井俊也, 枝廣育実, 白川裕章, 勝田隼一郎, 田中康之, 高橋弘充, 水野恒史, 深沢泰司, 村上浩章, 小林翔悟, 三宅克馬, 小野光, 室田優紀, 中澤知洋, 牧島一夫, 佐藤悟朗, 片岡淳, 一戸悠人, 内田悠介, 桂川美穂, 武田伸一郎, 佐藤理江, 川原田円, 原山淳, 小高浩和, 林克洋, 太田方之, 渡辺伸, 国分紀秀, 高橋忠幸, 木下将臣, 山岡和貴, 田島宏康, 谷津陽一, 内山秀樹, 斉藤新也, 湯浅孝行

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.23PDK-5  2015.03

    J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮影検出器(HXI)の現状FMの完成

    中澤知洋, 国分紀秀, 佐藤悟朗, 川原田円, 佐藤理江, 渡辺伸, 高橋忠幸, 太田方之, 小高裕和, 武田伸一郎, 原山淳, 斉藤新也, 湯浅孝行, 谷津陽一, 内山秀樹, 田島宏康, 山岡和貴, 深沢泰司, 水野恒史, 大野雅功, 高橋弘充, 勝田隼一郎, 寺田幸功, 牧島一夫, 片岡淳, 野田博文, 榎戸輝揚, 田中孝明, 内山泰伸, 中森健之, LIMOUSIN Olivier, LAURENT Philippe, LEBRUN Francois, 櫻井壮希, 笹野理, 中野俊男, 小林翔悟, 村上浩章, 小野光, 加藤佑一

    日本天文学会年会講演予稿集   2015   262  2015.02

    J-GLOBAL

  • 24aDJ-2 The launch of micro-satellite TSUBAME for Hard X-ray Polarimetry (II)

    Yatsu Y, Moriyama N, Kimura S, Kataoka J, Nakamori T, Kubo S, Kurita S, Ohuchi H, Arimoto M, Kawai N, Matsushita M, Kawajiri S, Nagasu T, Matunaga S

    Meeting Abstracts of the Physical Society of Japan   70 ( 0 )  2015

    CiNii

  • 福島県浪江町の里山における放射性セシウムの分布と動態(2)

    黒島碩人, 緒方裕子, 大河内博, 床次眞司, 反町篤行, 細田正洋, 片岡淳

    大気環境学会年会講演要旨集   55th   491  2014.08

    J-GLOBAL

  • OISTER・すざくによる2FGL J2339.6‐0532の観測

    谷津陽一, 橘優太郎, 大内遥河, 有元誠, 斉藤嘉彦, 河合誠之, 片岡淳, 高橋洋介, 柴田晋平, 関口和寛, 黒田大介, 花山秀和, 磯貝瑞希, 渡辺誠, 橋本修, 諸隈智貴, 高橋英則, 舘内謙, 村田勝寛, 永山貴宏, 面高俊宏, 吉田道利, ALI Gamal B, MOHAMED A. Essam, 秋田谷洋, 高橋隼, 奥村真一郎, 野上大作, 大朝由美子

    日本天文学会年会講演予稿集   2014   75  2014.08

    J-GLOBAL

  • Development of a prototype of time-over-threshold based small animal PET scanner

    K. Shimazoe, H. Takahashi, K. Kamada, A. Yoshikawa, K. Kumagai, J. Kataoka, S. Itoh, H. Sato, Y. Usuki

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   753   84 - 90  2014.07

     View Summary

    A time-over-threshold (ToT)-based positron emission tomography (TODPET) scanner was designed and fabricated. The PET scanner consisted of eight block detectors, each of which is composed of a 12 12 array of 2 210 mm 3 Pr:LuAG crystals individually coupled with a 12 12 UV-enhanced avalanche photodiode (APD) array. The APDs were individually read out using a custom-designed time-over-threshold application-specific integrated circuit (ASIC) and field-programmable gate array (FPGA) readout system. The PET scanner has an energy resolution of 10% and a time resolution of 4.2 ns. A spatial resolution of 1.17 mm (FWHM) was demonstrated in the initial results. © 2014 Elsevier B.V.

    DOI

  • 29pTK-6 Development status of the Hard X-ray Imager (HXI) onboard ASTRO-H

    Kawaharada Madoka, Kokubun Motohide, Nakazawa Kazuhiro, Sato Goro, Uchiyama Hideki, Uchiyama Yasunobu, Enoto Teruaki, Ohta Masayuki, Ohno Masanori, Odaka Hirokazu, Kataoka Jun, Sato Rie, Harayama Atsushi, Takahashi Tadayuki, Takahashi Hiromitsu, Takeda Shin'ichiro, Tajima Hiroyasu, Tanaka Takaaki, Terada Yukikatsu, Fukazawa Yasushi, Makishima Kazuo, Mizuno Tsunefumi, Yatsu Yoichi, Yamaoka Kazutaka, Yuasa Takayuki, Watanabe Shin, Laurent Philippe, Lebrun Francois, Limousin Olivier, the HXI team

    Meeting abstracts of the Physical Society of Japan   69 ( 1 ) 129 - 129  2014.03

    CiNii

  • 29pTK-8 Development of Soft Gamma-ray Detector (SGD) onboard ASTRO-H

    Ohta M., Tajima H., Fukazawa Y., Watanabe S., Uchiyama H., Uchiyama Y., Enoto T., Ohno M., Odaka H., Kataoka J., Kawaharada M., Kokubun M., Sato G., Sato R., Takahashi T., Takahashi H., Takeda S., Tashiro S., Tanaka T., Terada Y., Nakazawa K., Nakamori T., Noda H., Hayashi K., Harayama A., Blandford Roger, Makishima K., Madejski Grzegorz, Laurent Philippe, Limousin Olivier, Lebrun Francois, the SGD team

    Meeting abstracts of the Physical Society of Japan   69 ( 1 ) 129 - 129  2014.03

    CiNii

  • MPPCを用いた広角指向性を持つ簡易放射線検出器の開発

    中森健之, 武部瑞希, 郡司修一, 佐藤浩樹, 伊藤繁記, 吉野将生, 薄善行, 片岡淳

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   61st   ROMBUNNO.18A-F1-3  2014.03

    J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮像検出器(HXI)開発の現状

    佐藤悟朗, 国分紀秀, 中澤知洋, 高橋忠幸, 渡辺伸, 川原田円, 太田方之, 佐藤理江, 武田伸一郎, 小高裕和, 湯浅孝行, 林克洋, 原山淳, 牧島一夫, 野田博文, 片岡淳, 谷津陽一, 中森健之, 内山秀樹, 田島宏康, 山岡和貴, 深沢泰司, 水野恒史, 高橋弘充, 大野雅功, 寺田幸功, 榎戸輝揚, 田中孝明, 内山泰伸, LIMOUSIN Olivier, LAURENT Philippe, LEBRUN Francois

    日本天文学会年会講演予稿集   2014   275  2014.02

    J-GLOBAL

  • 18pSB-3 CTA Report 75 : General Report

    Teshima Masahiro

    Meeting Abstracts of the Physical Society of Japan   69.2.1   32  2014

    DOI CiNii

  • ASTRO-H衛星搭載硬X線軟ガンマ線検出器におけるBGOアクティブシールドの開発状況

    大野雅功, 徳田伸矢, 中村竜, 高橋弘充, 深沢泰司, 村上浩章, 小林翔悟, 櫻井壮希, 笹野理, 鳥井俊輔, 中澤和洋, 牧島一夫, 山岡和貴, 田島宏康, 内山秀樹, 佐藤理江, 萩野浩一, 湯浅孝行, 佐藤悟朗, 渡辺伸, 国分紀秀, 高橋忠幸, 森國城, 谷津陽一, 片岡淳, 齋藤龍彦, 吉野将生, 中森健之

    日本物理学会講演概要集   69 ( 1 )  2014

    J-GLOBAL

  • 30aTK-12 Flight operation of the gamma-ray burst polarimeter satellite TSUBAME

    Yatsu Yoichi, Nakamori Takeshi, Kubo Shin, Ito Kei, Kurita Shin, Arimoto Makoto, Kawai Nobuyuki, Matsushita Masanori, Matsunaga Saburo, Kimura Shin'ichi, Kataoka Jun

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 )  2014

    CiNii

  • 大面積MPPC array を用いた放射線検出器の最前線

    片岡 淳

    放射線(応用物理学会・放射線分科会)   39 ( 3 ) 117 - 126  2014

  • Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    J. Kataoka, A. Kishimoto, T. Nishiyama, T. Fujita, K. Takeuchi, T. Kato, T. Nakamori, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, K. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   732   403 - 407  2013.12  [Refereed]

     View Summary

    The release of radioactive isotopes (mainly Cs-137, Cs-134 and till) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just similar to 10 cm(2) in size. Despite its compactness, the camera realizes a wide 180 degrees field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 mu Sv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10 degrees (FWHM). The 3D position sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5 x 14 x 16 cm(3) in size) being fabricated by Hamamatsu Photonics K. K. Although the camera still operates in non-DOI mode, angular resolution as high as 14 degrees (FWHM) was achieved with an integration time of 30s for the assumed hotspot described above. (C) 2013 Elsevier B.V. All tights reserved.

    DOI

  • SUZAKU OBSERVATIONS OF THE DIFFUSE X-RAY EMISSION ACROSS THE FERMI BUBBLES' EDGES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, L. Stawarz, Y. Takahashi, Y. Takeuchi, H. Tsunemi, M. Kimura, Y. Takei, C. C. Cheung, Y. Inoue, T. Nakamori

    ASTROPHYSICAL JOURNAL   779 ( 1 ) 57 - 72  2013.12  [Refereed]

     View Summary

    We present Suzaku X-ray observations along two edge regions of the Fermi Bubbles, with eight similar or equal to 20 ks pointings across the northern part of the North Polar Spur (NPS) surrounding the north bubble and six across the southernmost edge of the south bubble. After removing compact X-ray features, diffuse X-ray emission is clearly detected and is well reproduced by a three-component spectral model consisting of unabsorbed thermal emission (temperature kT similar or equal to 0.1 keV) from the Local Bubble, absorbed kT similar or equal to 0.3 keV thermal emission related to the NPS and/or Galactic halo (GH), and a power-law component at a level consistent with the cosmic X-ray background. The emission measure (EM) of the 0.3 keV plasma decreases by similar or equal to 50% toward the inner regions of the northeast bubble, with no accompanying temperature change. However, such a jump in the EM is not clearly seen in the south bubble data. While it is unclear whether the NPS originates from a nearby supernova remnant or is related to previous activity within or around the Galactic center, our Suzaku observations provide evidence that suggests the latter scenario. In the latter framework, the presence of a large amount of neutral matter absorbing the X-ray emission as well as the existence of the kT similar or equal to 0.3 keV gas can be naturally interpreted as a weak shock driven by the bubbles' expansion in the surrounding medium, with velocity v(exp) similar or equal to 300 km s(-1) (corresponding to shock Mach number M similar or equal to 1.5), compressing the GH gas to form the NPS feature. We also derived an upper limit for any non-thermal X-ray emission component associated with the bubbles and demonstrate that, in agreement with the aforementioned findings, the non-thermal pressure and energy estimated from a one-zone leptonic model of its broadband spectrum, are in rough equilibrium with that of the surrounding thermal plasma.

    DOI

  • Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    J. Kataoka, A. Kishimoto, T. Nishiyama, T. Fujita, K. Takeuchi, T. Kato, T. Nakamori, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, K. Yamamoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   732   403 - 407  2013.12

     View Summary

    The release of radioactive isotopes (mainly Cs-137, Cs-134 and till) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just similar to 10 cm(2) in size. Despite its compactness, the camera realizes a wide 180 degrees field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 mu Sv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10 degrees (FWHM). The 3D position sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5 x 14 x 16 cm(3) in size) being fabricated by Hamamatsu Photonics K. K. Although the camera still operates in non-DOI mode, angular resolution as high as 14 degrees (FWHM) was achieved with an integration time of 30s for the assumed hotspot described above. (C) 2013 Elsevier B.V. All tights reserved.

    DOI

  • SUZAKU OBSERVATIONS OF THE DIFFUSE X-RAY EMISSION ACROSS THE FERMI BUBBLES' EDGES

    J. Kataoka, M. Tahara, T. Totani, Y. Sofue, L. Stawarz, Y. Takahashi, Y. Takeuchi, H. Tsunemi, M. Kimura, Y. Takei, C. C. Cheung, Y. Inoue, T. Nakamori

    ASTROPHYSICAL JOURNAL   779 ( 1 ) 57 - 72  2013.12

     View Summary

    We present Suzaku X-ray observations along two edge regions of the Fermi Bubbles, with eight similar or equal to 20 ks pointings across the northern part of the North Polar Spur (NPS) surrounding the north bubble and six across the southernmost edge of the south bubble. After removing compact X-ray features, diffuse X-ray emission is clearly detected and is well reproduced by a three-component spectral model consisting of unabsorbed thermal emission (temperature kT similar or equal to 0.1 keV) from the Local Bubble, absorbed kT similar or equal to 0.3 keV thermal emission related to the NPS and/or Galactic halo (GH), and a power-law component at a level consistent with the cosmic X-ray background. The emission measure (EM) of the 0.3 keV plasma decreases by similar or equal to 50% toward the inner regions of the northeast bubble, with no accompanying temperature change. However, such a jump in the EM is not clearly seen in the south bubble data. While it is unclear whether the NPS originates from a nearby supernova remnant or is related to previous activity within or around the Galactic center, our Suzaku observations provide evidence that suggests the latter scenario. In the latter framework, the presence of a large amount of neutral matter absorbing the X-ray emission as well as the existence of the kT similar or equal to 0.3 keV gas can be naturally interpreted as a weak shock driven by the bubbles' expansion in the surrounding medium, with velocity v(exp) similar or equal to 300 km s(-1) (corresponding to shock Mach number M similar or equal to 1.5), compressing the GH gas to form the NPS feature. We also derived an upper limit for any non-thermal X-ray emission component associated with the bubbles and demonstrate that, in agreement with the aforementioned findings, the non-thermal pressure and energy estimated from a one-zone leptonic model of its broadband spectrum, are in rough equilibrium with that of the surrounding thermal plasma.

    DOI

  • Development of a flight model of micro-satellite for the X-ray polarimetry of gamma-ray bursts "TSUBAME"

    Yatsu Youici, Kurita Shin, Ito Kei, Arimoto Makoto, Tokoyoda Kazuki, Kawai Nobuyuki, Kamiya Takashi, Kitamura Shogo, Matsunaga Saburo, Kataoka Jun, Nakamori Takeshi, Kubo Shin, the TSUBAME team

    Meeting abstracts of the Physical Society of Japan   68 ( 2 ) 111 - 111  2013.08

    CiNii

  • Development of Flight Model for Soft Gamma-ray Detector onboard ASTRO-H

    Tajima Hiroyasu, Blandford Roger, Madejski Grzegorz, Laurent Philippe, Limousin Olivier, Lebrun Frangois, the SGD team

    Meeting abstracts of the Physical Society of Japan   68 ( 2 ) 110 - 110  2013.08

    CiNii

  • ASTRO‐H衛星搭載硬X線撮像検出器(HXI)の開発の現状

    佐藤悟朗, 国分紀秀, 中澤知洋, 内山秀樹, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 小高裕和, 片岡淳, 川原田円, 佐藤理江, 高橋忠幸, 高橋弘充, 武田伸一郎, 田島宏康, 田中孝明, 寺田幸功, 深沢泰司, 牧島一夫, 水野恒史, 谷津陽一, 山岡和貴, 湯浅孝行, 渡辺伸, LIMOUSIN Olivier, LAURENT Philippe, LEBRUN Francois

    日本物理学会講演概要集   68 ( 2 ) 110  2013.08

    J-GLOBAL

  • ASTRO‐H衛星搭載型アクティブシールド系の受け入れ試験及び動作検証

    徳田伸矢, 大野雅功, 深澤泰司, 高橋弘充, 中村竜, 鳥井俊輔, 笹野理, 村上浩章, 中澤知洋, 牧島一夫, 林克洋, 佐藤理江, 渡辺伸, 湯浅孝行, 国分紀秀, 内山秀樹, 片岡淳, 田島宏康, 山岡和貴, 谷津陽一, 中森健之, 米徳大輔

    日本天文学会年会講演予稿集   2013   293  2013.08

    J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮像検出器(HXI)の現状~FM製造の現状と予想性能~

    中澤知洋, 国分紀秀, 川原田円, 佐藤悟朗, 牧島一夫, 渡辺伸, 高橋忠幸, 佐藤理江, 太田方之, 小高裕和, 武田伸一郎, 湯浅孝行, 中森健之, 片岡淳, 谷津陽一, 内山秀樹, 田島宏康, 山岡和貴, 深沢泰司, 水野恒史, 大野雅功, 高橋弘充, 寺田幸功, 榎戸輝揚, 田中孝明, 内山泰伸, LIMOUSIN Olivier, LAURENT Philippe, LEBRUN Francois

    日本天文学会年会講演予稿集   2013   293  2013.08

    J-GLOBAL

  • 29pEA-5 Deep X-ray observation of Centaurus A Southern lobe with Suzaku

    Tanaka Y., Fukazawa Y., Kataoka J., Takahashi T., Takei Y., Takeuchi Y., Stawarz L., Majejski G., O'Sullivan S. P., Cheung C. C., Feain I. J., Gandhi P., Hardcastle M. J., Ostrowski M., Reville B., Siemiginowska A., Simionescu A., Werner N.

    Meeting abstracts of the Physical Society of Japan   68 ( 1 ) 308 - 308  2013.03

    CiNii

  • 28pBE-2 Ground Calibration of the Balloon-Borne Soft Gamma-Ray Polarimeter PoGOLite

    Kawano Takafumi, Axelsson M., Jackson M., Kiss M., Klamra W., Kole M., Larsson S., Moretti E., Pearce M., Ryde F., Rydstrom S., Olofsson G., Floren H-G., Madejski G., Varner G., PoGOLite team

    Meeting abstracts of the Physical Society of Japan   68 ( 1 ) 137 - 137  2013.03

    CiNii

  • Astro‐H衛星搭載軟ガンマ線検出器の開発(2012年度後半)

    水野恒史, 田島宏康, 深沢泰司, 渡辺伸, 内山秀樹, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 小高裕和, 片岡淳, 川原田円, 国分紀秀, 佐藤悟朗, 佐藤理江, 高橋忠幸, 高橋弘充, 武田伸一郎, 田代信, 田中孝明, 寺田幸功, 中澤知洋, 中森健之, BLANDFORD Roger, 牧島一夫, MADEJSKI Grzegorz, 森國城, 谷津陽一, 山田真也, 湯浅孝行, 米徳大輔, LAURENT Philippe, LIMOUSIN Olivier, LEBRUN Francois

    日本物理学会講演概要集   68 ( 1 ) 134  2013.03

    J-GLOBAL

  • ASTRO‐H衛星搭載BGOアクティブシールドの信号処理におけるデジタルフィルタの改良

    後藤国広, 松岡正之, 徳田伸矢, 高橋弘充, 大野雅功, 深沢泰司, 湯浅孝行, 佐藤悟朗, 渡辺伸, 国分紀秀, 高橋忠幸, 鳥井俊輔, 中澤知洋, 齋藤龍彦, 中森健之, 片岡淳, 田島宏康

    日本天文学会年会講演予稿集   2013   277  2013.02

    J-GLOBAL

  • ASTRO‐H衛星搭載装置のアクティブシールド用BGO試験の現状(2)

    西田瑛量, 牧島一夫, 中澤知洋, 内山秀樹, 笹野理, 村上浩章, 佐藤理江, 山岡和貴, 深澤泰司, 高橋弘充, 林克洋, 徳田伸矢, 片岡淳, 中森健之, 齋藤龍彦, 谷津陽一

    日本天文学会年会講演予稿集   2013   277  2013.02

    J-GLOBAL

  • Development of a time over threshold based pet detector

    Kenji Shimazoe, Hiroyuki Takahashi, Kei Kamada, Yoshiyuki Usuki, Masao Yoshino, Jun Kataoka, Takayuki Yanagida, Akira Yoshikawa, Kazuaki Kumagai

    Proceedings of the 26th Workshop on Radiation Detectors and Their Uses     74 - 81  2012.12

  • TOWARD IDENTIFYING THE UNASSOCIATED GAMMA-RAY SOURCE 1FGL J1311.7-3429 WITH X-RAY AND OPTICAL OBSERVATIONS

    J. Kataoka, Y. Yatsu, N. Kawai, Y. Urata, C. C. Cheung, Y. Takahashi, K. Maeda, T. Totani, R. Makiya, H. Hanayama, T. Miyaji, A. Tsai

    ASTROPHYSICAL JOURNAL   757 ( 2 ) 176 - 184  2012.10

     View Summary

    We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoidal optical modulation of Delta m similar to 2 mag with a period of similar or equal to 1.5 hr in the Rc, r', and g' bands. Moreover, we found that the amplitude of the modulation and peak intensity changed by greater than or similar to 1 mag and similar to 0.5 mag, respectively, over our total six nights of observations from 2012 March to May. Combined with Swift UVOT data, the optical-UV spectrum is consistent with a blackbody temperature, kT similar or equal to 1 eV and the emission volume radius R-bb similar or equal to 1.5 x 10(4) d(kpc) km (d(kpc) is the distance to the source in units of 1 kpc). In contrast, deep Suzaku observations conducted in 2009 and 2011 revealed strong X-ray flares with a light curve characterized with a power spectrum density of P(f) proportional to f(-2.0 +/- 0.4), but the folded X-ray light curves suggest an orbital modulation also in X-rays. Together with the non-detection of a radio counterpart, and significant curved spectrum and non-detection of variability in gamma-rays, the source may be the second "radio-quiet" gamma-ray emitting millisecond pulsar candidate after 1FGL J2339.7-0531, although the origin of flaring X-ray and optical variability remains an open question.

    DOI

  • TOWARD IDENTIFYING THE UNASSOCIATED GAMMA-RAY SOURCE 1FGL J1311.7-3429 WITH X-RAY AND OPTICAL OBSERVATIONS

    J. Kataoka, Y. Yatsu, N. Kawai, Y. Urata, C. C. Cheung, Y. Takahashi, K. Maeda, T. Totani, R. Makiya, H. Hanayama, T. Miyaji, A. Tsai

    ASTROPHYSICAL JOURNAL   757 ( 2 ) 176 - 184  2012.10  [Refereed]

     View Summary

    We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoidal optical modulation of Delta m similar to 2 mag with a period of similar or equal to 1.5 hr in the Rc, r', and g' bands. Moreover, we found that the amplitude of the modulation and peak intensity changed by greater than or similar to 1 mag and similar to 0.5 mag, respectively, over our total six nights of observations from 2012 March to May. Combined with Swift UVOT data, the optical-UV spectrum is consistent with a blackbody temperature, kT similar or equal to 1 eV and the emission volume radius R-bb similar or equal to 1.5 x 10(4) d(kpc) km (d(kpc) is the distance to the source in units of 1 kpc). In contrast, deep Suzaku observations conducted in 2009 and 2011 revealed strong X-ray flares with a light curve characterized with a power spectrum density of P(f) proportional to f(-2.0 +/- 0.4), but the folded X-ray light curves suggest an orbital modulation also in X-rays. Together with the non-detection of a radio counterpart, and significant curved spectrum and non-detection of variability in gamma-rays, the source may be the second "radio-quiet" gamma-ray emitting millisecond pulsar candidate after 1FGL J2339.7-0531, although the origin of flaring X-ray and optical variability remains an open question.

    DOI

  • 14pSP-6 Development of detectors for gamma-ray burst mounted onultra-small satellite TSUBAME

    Tokoyoda Kazuki

    Meeting abstracts of the Physical Society of Japan   67 ( 2 ) 121 - 121  2012.08

    CiNii

  • Astro‐H衛星搭載軟ガンマ線検出器の開発

    深沢泰司, 田島宏康, 渡辺伸, 内山秀樹, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 小高裕和, 片岡淳, 川原田円, 国分紀秀, 佐藤悟朗, 佐藤理江, 高橋忠幸, 高橋弘充, 武田伸一郎, 田代信, 田中孝明, 寺田幸功, 中澤知洋, 中森健之, 牧島一夫, 水野恒史, 森國城, 谷津陽一, 山田真也, 湯浅孝行, 米徳大輔, BLANDFORD Roger, MADEJSKI Grzegorz, LAURENT Philippe, LIMOUSIN Olivier, LEBRUN Francois

    日本物理学会講演概要集   67 ( 2 ) 119  2012.08

    J-GLOBAL

  • ASTRO‐H衛星に搭載するアクティブシールド用BGO試験の現状

    西田瑛量, 牧島一夫, 中澤知洋, 内山秀樹, 笹野理, 佐藤理江, 深沢泰司, 高橋弘充, 徳田伸矢, 片岡淳, 中森健之, 谷津陽一

    日本天文学会年会講演予稿集   2012   276  2012.08

    J-GLOBAL

  • Expected radiation damage of reverse-type APDs for the Astro-H mission

    J. Kataoka, T. Saito, M. Yoshino, H. Mizoma, T. Nakamori, Y. Yatsu, Y. Ishikawa, Y. Matsunaga, H. Tajima, M. Kokubun, P. G. Edwards

    JOURNAL OF INSTRUMENTATION   7  2012.06

     View Summary

    Scheduled for launch in 2014, Astro-H is the sixth Japanese X-ray astronomy satellite mission. More than 60 silicon avalanche photodiodes (Si-APDs; hereafter APDs) will be used to read out BGO scintillators, which are implemented to generate a veto signal to reduce background contamination for the hard X-ray imager (HXI) and a soft gamma-ray detector (SGD). To date, however, APDs have rarely been used in space experiments. Moreover, strict environmental tests are necessary to guarantee APD performance for missions expected to extend beyond five years. The radiation hardness of APDs, as for most semiconductors, is particularly crucial, since radiation in the space environment is severe. In this paper, we present the results of radiation tests conducted on reverse-type APDs (provided by Hamamatsu Photonics) irradiated by gamma rays (Co-60) and 150 MeV protons. We show that, even under the same 100 Gy dose, high energy protons can cause displacement (bulk) damage in the depletion region and possibly change the activation energy, whereas gamma-ray irradiation is less prone to cause damage, because ionization damage dominates only the surface region. We also present quantitative guidance on how to estimate APD noise deterioration over a range of temperatures and radiation doses. As a practical example, we discuss the expected degradation of the BGO energy threshold for the generation of veto signals, following several years of Astro-H operation in Low Earth Orbit (LEO), and directly compare it to experimental results obtained using a small BGO crystal.

    DOI

  • Time over Threshold based digital animal PET (TODPET)

    K. Shimazoe, Y. Wang, H. Takahashi, K. Kamada, M. Yoshino, J. Kataoka, Y. Yamaya, T. Yanagida, A. Yoshikawa, K. Kumagai

    IEEE Nuclear Science Symposium Conference Record     3267 - 3271  2012.03

     View Summary

    We have developed Time over Threshold (ToT) based Pr:LuAG-APD PET (TODPET) tomograph with a mixed signal front-end. The tomograph consists of 8 block detectors, each of which is composed of a 12 x 12 array of 2 x 2 x 10mm3Pr:LuAG crystals individually coupled with 12 x 12 UV-enhanced APD arrays. The APDs are individually read out with a custom-designed Time over Threshold ASIC and FPGA readout system. Developed PET tomograph has the energy resolution of 10% and the time resolution of 4.2ns. The 1.76mm spatial resolution (FWHM) is achieved for the first result. © 2011 IEEE.

    DOI

  • 27aGC-4 Measurement of large BGO crystals for a satellite by APD

    Sasano M., Nishioka H., Okuyama S., Nakazawa K., Makishima K., Yuasa T., Yamada S., Kataoka J., Fukazawa Y., Hanabata Y., Hayashi K., Tajima H., Okumura A.

    Meeting abstracts of the Physical Society of Japan   67 ( 1 ) 110 - 110  2012.03

    CiNii

  • 27aGJ-1 Development of detectors for gamma-ray burst mounted on ultra-small satellite TSUBAME

    Kawakami Kosuke

    Meeting abstracts of the Physical Society of Japan   67 ( 1 ) 142 - 142  2012.03

    CiNii

  • 25aGC-8 Development of an ultra-fast ASIC for future PET scanners using TOF-capable MPPC detectors and its performance test

    Matsuda H, Kataoka J, Ikeda H, Nakamori T, Miura T, Kato T, Anbe T, Ishikawa Y, Sato K, Yamamura K, Nakamura S, Kawabata N

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )  2012.03

    CiNii

  • ASTRO‐H衛星搭載BGOシールド統合試験に向けたアナログ信号処理部の検証

    斎藤龍彦, 吉野将生, 溝間青樹, 中森健之, 片岡淳, 川上孝介, 谷津陽一, 後藤国広, 松岡正之, 高橋弘充, 大野雅功, 深沢泰司, 渡辺伸, 国分紀秀, 高橋忠幸, 森國城, 西田瑛量, 笹野理, 鳥井俊輔, 中澤知洋, 牧島一夫, 田島宏康, 内堀幸夫, 北村尚

    日本物理学会講演概要集   67 ( 1 ) 138  2012.03

    J-GLOBAL

  • ASTRO‐H衛星搭載の硬X線・軟ガンマ線検出器シールド部における信号処理用デジタルフィルタ開発

    後藤国広, 松岡正之, 高橋弘充, 大野雅功, 深沢泰司, 湯浅孝行, 国分紀秀, 高橋忠幸, 中澤知洋, 吉野将生, 齋藤龍彦, 中森健之, 片岡淳, 田島宏康

    日本物理学会講演概要集   67 ( 1 ) 32  2012.03

    J-GLOBAL

  • 硬X線撮像検出器HXIに向けたアクティブシールド機能の検証実験

    鳥井俊輔, 笹野理, 西田瑛量, 中澤知洋, 牧島一夫, 後藤国広, 松岡正之, 高橋弘充, 大野雅功, 深沢泰司, 湯浅孝行, 渡辺伸, 国分紀秀, 高橋忠幸, 森國城, 吉野将生, 齋藤龍彦, 溝間青樹, 中森健之, 片岡淳, 田島宏康

    日本物理学会講演概要集   67 ( 1 ) 140  2012.03

    J-GLOBAL

  • Astro‐H衛星搭載軟ガンマ線検出器の開発

    田島宏康, 深沢泰司, 渡辺伸, 内山秀樹, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 小高裕和, 片岡淳, 川原田円, 国分紀秀, 佐藤悟朗, 高橋忠幸, 高橋弘充, 武田伸一郎, 田代信, 田中孝明, 寺田幸功, 中澤知洋, 中森健之, BLANDFORD Roger, 牧島一夫, MADEJSKI Grzegorz, 水野恒史, 森國城, 谷津陽一, 山岡和貴, 山田真也, 湯浅孝行, 米徳大輔, LAURENT Philippe, LIMOUSIN Olivier, LEBRUN Francois

    日本物理学会講演概要集   67 ( 1 ) 139  2012.03

    J-GLOBAL

  • ASTRO‐H衛星搭載BGOシールド統合試験に向けたアナログ信号処理部の検証

    吉野将生, 斎藤龍彦, 溝間青樹, 中森健之, 片岡淳, 後藤国広, 松岡正之, 高橋弘充, 大野雅功, 深澤泰司, 渡辺伸, 国分紀秀, 高橋忠幸, 森國城, 笹野理, 鳥居俊輔, 中澤知洋, 牧島一夫, 川上孝介, 谷津陽一, 田島宏康, 内堀幸夫, 北村尚

    日本天文学会年会講演予稿集   2012   287  2012.02

    J-GLOBAL

  • ASTRO‐H衛星搭載HXI/SGDの電源制御回路部(CPMU)の開発

    原山淳, 川原田円, 渡辺伸, 太田方之, 国分紀秀, 高橋忠幸, 田島宏康, 深沢泰司, 中澤知洋, 片岡淳, 寺田幸功

    日本天文学会年会講演予稿集   2012   284  2012.02

    J-GLOBAL

  • 26pGJ-3 Development status of the Hard X-ray Imager (HXI) onboard ASTRO-H

    Kawaharada Madoka, Nakazawa Kazuhiro, Uchiyama Hideki, Makishima Kazuo, Mizuno Tsunefumi, Takahashi Hiromitsu, Ohno Masanori, Kataoka Jun, Nakamori Takeshi, Terada Yukikatsu, Kokubun Motohide, Yatsu Yoichi, Yamaoka Kazutaka, Tajima Hiroyasu, Tanaka Takaaki, Enoto Teruaki, Philippe Laurent, Francois Lebrun, Olivier Limousin, Sato Goro, Watanabe Shin, Tanaka Yasayuki, Ohta Masayuki, Yuasa Takayuki, Odaka Hirokazu, Takahashi Tadayuki

    Meeting Abstracts of the Physical Society of Japan   67 ( 1 ) 138 - 138  2012

    DOI CiNii

  • BROAD-LINE RADIO GALAXIES OBSERVED WITH FERMI-LAT: THE ORIGIN OF THE GeV gamma-RAY EMISSION

    J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

    ASTROPHYSICAL JOURNAL   740 ( 1 ) 29 - 44  2011.10

     View Summary

    We report on a detailed investigation of the gamma-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is &gt;= 1% on average for BLRGs, whereas it is &lt;= 0.1% for Seyfert 1 galaxies.

    DOI

  • BROAD-LINE RADIO GALAXIES OBSERVED WITH FERMI-LAT: THE ORIGIN OF THE GeV gamma-RAY EMISSION

    J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

    ASTROPHYSICAL JOURNAL   740 ( 1 ) 29 - 44  2011.10  [Refereed]

     View Summary

    We report on a detailed investigation of the gamma-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is &gt;= 1% on average for BLRGs, whereas it is &lt;= 0.1% for Seyfert 1 galaxies.

    DOI

  • ASTRO‐H衛星搭載軟ガンマ線検出器(SGD)の開発の現状

    渡辺伸, 田島宏康, 深沢泰司, 内山秀樹, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 小高裕和, 片岡淳, 川原田円, 国分紀秀, 佐藤悟朗, 高橋弘充, 高橋忠幸, 田代信, 田中孝明, 寺田幸功, 中澤知洋, 中森健之, BLANDFORD Roger, 牧島一夫, MADEJSKI Grzegorz, 水野恒史, 森國城, 谷津陽一, 湯浅孝行, LAURENT Philippe, LIMOUSIN Olivier, LEBRUN Francois

    日本物理学会講演概要集   66 ( 2 ) 112  2011.08

    J-GLOBAL

  • ASTRO‐H衛星搭載BGOアクティブシールドの信号処理におけるデジタルフィルタの最適化

    後藤国広, 松岡正之, 高橋弘充, 大野雅功, 深沢泰司, 湯浅孝行, 国分紀秀, 高橋忠幸, 中澤知洋, 吉野将生, 齋藤龍彦, 中森健之, 片岡淳, 田島宏康

    日本天文学会年会講演予稿集   2011   305  2011.08

    J-GLOBAL

  • ASTRO‐H搭載BGOシールド用APDセンサ及びアナログシステムの開発(II)

    吉野将生, 齋藤龍彦, 中森健之, 片岡淳, 国分紀秀, 渡辺伸, 大野雅功, 湯浅孝行, 高橋忠幸, 森國城, 西岡博之, 笹野理, 中澤知洋, 牧島一夫, 川上孝介, 谷津陽一, 松岡正之, 後藤国広, 高橋弘充, 深澤泰司, 田島宏康

    日本天文学会年会講演予稿集   2011   305  2011.08

    J-GLOBAL

  • ASTRO‐H HXI/SGD検出器搭載の高電圧電源部の開発

    原山淳, 川原田円, 渡辺伸, 太田方之, 国分紀秀, 高橋忠幸, 田島宏康, 深沢泰司, 中澤知洋, 片岡淳, 寺田幸功

    日本天文学会年会講演予稿集   2011   303  2011.08

    J-GLOBAL

  • 最先端の要素技術・装置開発研究(29)APDアレー放射線検出器の開発

    柳田健之, 吉田彰, 吉田彰, 吉野将生, 片岡淳, 島添健次, 高橋浩之, 鎌田圭, 遠藤貴範, 堤浩輔, 佐藤浩樹, 薄善行

    NIRS-R (National Inst. of Radiological Sciences)   ( 64 ) 87 - 89  2011.03

    J-GLOBAL

  • 28aGN-10 Observation of Gamma-ray Bursts with Soft Gamma-ray Detector onboard ASTRO-H

    Ohno Masanori, Watanabe Shin, Kawaharada Madoka, Ohta Masayuki, Sato Tamotsu, Kokubun Motohide, Takahashi Tadayuki, Tajima Hiroyasu, Tanaka Takaaki, Enoto Teruaki, Fukazawa Yasushi, Takahashi Hiromitsu, Hanabata Yoshitaka, Matsuoka Masayuki, Nakazawa Kazuhiro, Yuasa Takayuki, Nakajima Kenta, Nishioka Hiroyuki, Makishima Kazuo, Yamaoka Kazutaka, Kataoka Jun, Nakamori Takeshi, Yoshino Masao, Saito Tatsuhiko, Yonetoku Daisuke, Terada Yukikatsu, HXI, SGD team

    Meeting abstracts of the Physical Society of Japan   66 ( 1 ) 34 - 34  2011.03

    CiNii

  • 硬X線撮像検出器HXIに向けたアクティブシールド機能の検証実験

    鳥井俊輔, 中澤知洋, 内山秀樹, 湯浅孝之, 中島健太, 西岡博之, 櫻井壮希, 笹野理, 中野俊男, 牧島一夫, 国分紀秀, 渡辺伸, 高橋忠幸, 斉藤新也, 福山太郎, 佐藤有, 萩野浩一, 大野雅功, 田島宏康, 榎戸輝揚, 片岡淳, 中森健之, 谷津陽一, 深沢泰司

    日本物理学会講演概要集   66 ( 1 ) 123  2011.03

    J-GLOBAL

  • ASTRO‐H衛星搭載軟ガンマ線検出器(SGD)の開発の現状

    田中孝明, 内山泰伸, 榎戸輝揚, 太田方之, 大野雅功, 片岡淳, 川原田円, 国分紀秀, 佐藤悟朗, 高橋忠幸, 高橋弘充, 田島宏康, 田代信, 寺田幸功, 中澤知洋, 中森健之, 深沢泰司, BLANDFORD Roger, 牧島一夫, MADEJSKI Grzegorz, 水野恒史, 森國城, 谷津陽一, 山岡和貴, LAURENT Philippe, LIMOUSIN Olivier, LEBRUN Francois, 渡辺伸

    日本物理学会講演概要集   66 ( 1 ) 122  2011.03

    J-GLOBAL

  • ASTRO‐H搭載BGOシールド用APDセンサ及びアナログシステムの開発

    齋藤龍彦, 吉野将生, 中森健之, 片岡淳, 国分紀秀, 渡辺伸, 大野雅功, 高橋忠幸, 森國城, 西岡博之, 笹野理, 中澤知洋, 牧島一夫, 谷津陽一, 松岡正之, 高橋弘充, 深澤泰司, 田島宏康

    日本物理学会講演概要集   66 ( 1 ) 123  2011.03

    J-GLOBAL

  • 次期X線衛星ASTRO‐Hへ向けたBGO結晶シンチレータのAPD読み出しによる光収集効率の研究

    西岡博之, 笹野理, 湯浅孝行, 山田真也, 中澤知洋, 牧島一夫, 深沢泰司, 齋藤龍彦, 吉野将生, 中森健之, 片岡淳, 谷津陽一

    日本物理学会講演概要集   66 ( 1 ) 123  2011.03

    J-GLOBAL

  • 次期X線天文衛星ASTRO‐H搭載CdTe半導体検出器における放射化バックグラウンドの評価

    佐藤有, 大野雅功, 太田方之, 渡辺伸, 川原田円, 小高裕和, 古関優, 福山太郎, 斎藤新也, 萩野浩一, 国分紀秀, 高橋忠幸, 水野恒史, 平木一至, 林克洋, 西野翔, 道津匡平, 朴寅春, 深沢泰司, 田島宏康, 田中孝明, 榎戸輝揚, 中澤知洋, 内山秀樹, 湯浅孝之, 鳥井俊輔, 西岡博之, 櫻井壮希, 笹野理, 中野俊男, 牧島一夫, 片岡淳, 吉野将生

    日本天文学会年会講演予稿集   2011   256  2011.02

    J-GLOBAL

  • ASTRO‐H搭載BGOシールド用APDセンサ及びアナログシステムの開発

    吉野将生, 齋藤龍彦, 中森健之, 片岡淳, 国分紀秀, 渡辺伸, 大野雅功, 高橋忠幸, 森國城, 西岡博之, 笹野理, 中澤知洋, 牧島一夫, 川上孝介, 谷津陽一, 松岡正之, 花畑義隆, 高橋弘充, 深澤泰司, 田島宏康

    日本天文学会年会講演予稿集   2011   257  2011.02

    J-GLOBAL

  • ASTRO‐H搭載硬X線撮像検出器/軟ガンマ線検出器のアクティブシールド部におけるデジタルフィルタの開発

    松岡正之, 高橋弘充, 花畑義隆, 深沢泰司, 大野雅功, 国分紀秀, 高橋忠幸, 湯浅孝行, 中澤知洋, 吉野将生, 齋藤龍彦, 中森健之, 片岡淳, 田島宏康

    日本天文学会年会講演予稿集   2011   252  2011.02

    J-GLOBAL

  • Development of an APD-Based PET Module and Preliminary Resolution Performance of an Experimental Prototype Gantry

    Jun Kataoka, Hidenori Matsuda, Fumihiko Nishikido, Makoto Koizumi, Hirokazu Ikeda, Masao Yoshino, Takamasa Miura, Satoshi Tanaka, Yoshitaka Ishikawa, Nobuyuki Kawabata, Keiji Shimizu, Yusuke Matsunaga, Shunji Kishimoto, Hidetoshi Kubo, Yoshio Yanagida, Takeshi Nakamori

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   57 ( 5 ) 2448 - 2454  2010.10  [Refereed]

     View Summary

    The development of a high-resolution Positron Emission Tomography (PET) technique with sub-millimeter spatial resolution, which utilizes newly designed reverse-type APD-arrays, is uderway. All the detector blocks are modularized with the overall dimension of each module, including the APD array, LYSO scintillator matrix and Front-End Circuits (FECs), which are only 30 x 30 x 80 mm(3). Each APD device also has a monolithic 16 x 16 pixel structure with an active area of 1.0 mm(2) per pixel. The FEC includes two identical analog ASICs specifically designed for APDs with a noise characteristic of 560 + 30 e(-)/pF and a timing resolution of 460 ps (rms), respectively. An energy resolution of 13.7 +/- 1.1% (FWHM) with 662 keV gamma-rays was measured using the 16 x 16 arrays. At this stage a pair of module and coincidence circuits has been assembled into an experimental prototype gantry. Spatial resolutions of 0.9, 1.4, and 1.3 mm (FWHM) were obtained from FBP reconstructed images in preliminary experiments with a point source positioned centrally, and 1 and 5 mm off-center, respectively. Comparison with a Monte-Carlo simulation of a fully-designed gantry over a wider range of field-of-view showed good correlation with the experimental data. A simple but conceptual design of a DOI configuration is also proposed as a test example of a future APD-PET scanner.

    DOI

  • Development of an APD-Based PET Module and Preliminary Resolution Performance of an Experimental Prototype Gantry

    Jun Kataoka, Hidenori Matsuda, Fumihiko Nishikido, Makoto Koizumi, Hirokazu Ikeda, Masao Yoshino, Takamasa Miura, Satoshi Tanaka, Yoshitaka Ishikawa, Nobuyuki Kawabata, Keiji Shimizu, Yusuke Matsunaga, Shunji Kishimoto, Hidetoshi Kubo, Yoshio Yanagida, Takeshi Nakamori

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   57 ( 5 ) 2448 - 2454  2010.10

     View Summary

    The development of a high-resolution Positron Emission Tomography (PET) technique with sub-millimeter spatial resolution, which utilizes newly designed reverse-type APD-arrays, is uderway. All the detector blocks are modularized with the overall dimension of each module, including the APD array, LYSO scintillator matrix and Front-End Circuits (FECs), which are only 30 x 30 x 80 mm(3). Each APD device also has a monolithic 16 x 16 pixel structure with an active area of 1.0 mm(2) per pixel. The FEC includes two identical analog ASICs specifically designed for APDs with a noise characteristic of 560 + 30 e(-)/pF and a timing resolution of 460 ps (rms), respectively. An energy resolution of 13.7 +/- 1.1% (FWHM) with 662 keV gamma-rays was measured using the 16 x 16 arrays. At this stage a pair of module and coincidence circuits has been assembled into an experimental prototype gantry. Spatial resolutions of 0.9, 1.4, and 1.3 mm (FWHM) were obtained from FBP reconstructed images in preliminary experiments with a point source positioned centrally, and 1 and 5 mm off-center, respectively. Comparison with a Monte-Carlo simulation of a fully-designed gantry over a wider range of field-of-view showed good correlation with the experimental data. A simple but conceptual design of a DOI configuration is also proposed as a test example of a future APD-PET scanner.

    DOI

  • ASTRO‐H衛星搭載硬X線イメージャー(HXI)の開発の現状(V)

    渡辺伸, 国分紀秀, 川原田円, 佐藤悟朗, 大野雅功, 田中康之, 太田方之, 高橋忠幸, 中澤知洋, 牧島一夫, 片岡淳, 中森健之, 田島宏康, 田中孝明, 深沢泰司, 水野恒史, 高橋弘充, 谷津陽一, OLIVIER Limousin, LAURENT Philippe, LEBRUN Francois

    日本天文学会年会講演予稿集   2010   226  2010.08

    J-GLOBAL

  • ASTRO‐H衛星硬X線・軟ガンマ線検出器アクティブシールドの機構開発

    中島健太, 中澤知洋, 中野俊男, 西岡博之, 牧島一夫, 花畑義隆, 高橋弘充, 水野恒史, 深沢泰司, 山岡和貴, 田島宏康, 片岡淳, 大野雅功, 国分紀秀, 高橋忠幸, 渡辺伸, 田代信, 寺田幸功

    日本天文学会年会講演予稿集   2010   226  2010.08

    J-GLOBAL

  • 12pSL-12 Development of Trigger Logic and Signal Processing Firmware for the Compton Camera onboard Astro-II

    Ohno Masanori, Sato Tamotsu, Watanabe Shin, Kawaharada Madoka, Ohta Masayuki, Tanaka Yasuyuki, Odaka Hirokazu, Saito Shinya, Sasaki Chikako, Fukuyama Taro, Hagino Koichi, Kokubun Motohide, Takahashi Tadayuki, Tajima Hiroyasu, Tanaka Takaaki, Enoto Teruaki, Fukazawa Yasushi, Takahashi Hiromitsu, Hanabata Yoshitaka, Nakazawa Kazuhiro, Yuasa Takayuki, Nakajima Kenta, Nishioka Hiroyuki, Makishima Kazuo, Yamaoka Kazutaka, Kataoka Jun, Yoshino Masao, Yonetoku Daisuke, Terada Yukikatsu, IIXI, SGD team

    Meeting abstracts of the Physical Society of Japan   65 ( 2 ) 17 - 17  2010.08

    CiNii

  • 11pSG-2 PoGOLite気球実験のパスファインダーフライト(2) : データ取得システム(11pSG X線・γ線,宇宙線・宇宙物理領域)

    松岡 正之, 高橋 弘充, 米谷 光生, 水野 恒史, 深沢 泰司, 金井 義和, 河合 誠之, 片岡 淳, 釜江 常好, 田島 宏康, Madejski G., 高橋 忠幸, 郡司 修一, 湯浅 孝行, Pearce M., Jackson M., Kiss M., Mallol P., Bettolo C. Marini, Rydstrom S., PoGOLiteチーム

    日本物理学会講演概要集   65 ( 2 ) 81 - 81  2010.08

    CiNii

  • 11aSG-10 Development of hard X-ray polarimeter on board the ultrasmall satellite TSUBAME

    Enomoto Takahiro

    Meeting abstracts of the Physical Society of Japan   65 ( 2 ) 80 - 80  2010.08

    CiNii

  • PoGOLite気球実験のパスファインダーフライト(1):大気中性子モニター

    高橋弘充, 米谷光生, 松岡正之, 水野恒史, 深沢泰司, 金井義和, 河合誠之, 片岡淳, 釜江常好, 田島宏康, MADEJSKI G, 高橋忠幸, 郡司修一, 湯浅孝行, PEARCE M, JACKSON M, KISS M, MALLOL P, MARINI BETTOLO C, RYDSTROEM S, 柳田健之, 藤本裕, 横田有為, 吉川彰, 河口範明, 石津澄人, 福田健太郎, 須山敏尚, 渡辺賢一

    日本物理学会講演概要集   65 ( 2 ) 81  2010.08

    J-GLOBAL

  • ASTRO‐H衛星搭載軟ガンマ線検出器におけるアクティブシールドの効果の評価

    佐藤有, 大野雅功, 渡辺伸, 川原田円, 太田方之, 田中康之, 小高裕和, 福山太郎, 齋藤新也, 佐々木智香子, 萩野浩一, 国分紀秀, 高橋忠幸, 田島宏康, 田中孝明, 深沢泰司, 水野恒史, 平木一至, 林克洋, 西野翔, 道津匡平, PARK I, 中澤知洋, 湯浅孝行, 中島健太, 西岡博之, 野田博文, 鳥井俊輔, 牧島一夫, 片岡淳, 吉野将生

    日本物理学会講演概要集   65 ( 2 ) 81  2010.08

    J-GLOBAL

  • フェルミ衛星による活動銀河ジェット観測の新展開

    片岡 淳ほか

    日本天文学会誌   103   486  2010.08  [Refereed]

  • Response to the cosmic-ray heavy ion particles of hard X-ray and gamma-ray detectors on board the ASTRO-H satellite

    国分紀秀, 渡辺伸, 太田方之, 佐藤悟郎, 岸下徹一, 勝田隼一郎, 小高裕和, 石川真之介, 古関優, 佐々木智香子, 斎藤新也, 福山太郎, 中澤知洋, 奥村暁, 山田真也, 鳥井俊輔, 中島健太, 片岡淳, 吉野将生, 三浦大陽, 寺田幸功, 原山淳, 中嶋大, 出原寿紘, 内堀幸夫, 北村尚

    NIRS-M (Natl Inst Radiol Sci)   ( 234 ) 270 - 271  2010.06

    J-GLOBAL

  • 大面積APDアレーの開発と次世代PET技術への展望

    片岡 淳

    放射線(応用物理学会・放射線分科会)   35 ( 4 ) 277 - 287  2010.06  [Refereed]

  • gamma-RAY SPECTRAL EVOLUTION OF NGC 1275 OBSERVED WITH FERMI LARGE AREA TELESCOPE

    J. Kataoka, L. Stawarz, C. C. Cheung, G. Tosti, E. Cavazzuti, A. Celotti, S. Nishino, Y. Fukazawa, D. J. Thompson, W. F. McConville

    ASTROPHYSICAL JOURNAL   715 ( 1 ) 554 - 560  2010.05

     View Summary

    We report on a detailed investigation of the high-energy gamma-ray emission from NGC 1275, a well-known radio galaxy hosted by a giant elliptical located at the center of the nearby Perseus cluster. With the increased photon statistics, the center of the gamma-ray-emitting region is now measured to be separated by only 0.46 arcmin from the nucleus of NGC 1275, well within the 95% confidence error circle with radius similar or equal to 1.5 arcmin. Early Fermi Large Area Telescope (LAT) observations revealed a significant decade-timescale brightening of NGC 1275 at GeV photon energies, with a flux about 7 times higher than the one implied by the upper limit from previous EGRET observations. With the accumulation of one year of Fermi-LAT all-sky-survey exposure, we now detect flux and spectral variations of this source on month timescales, as reported in this paper. The average &gt; 100 MeV gamma-ray spectrum of NGC 1275 shows a possible deviation from a simple power-law shape, indicating a spectral cutoff around an observed photon energy of epsilon(gamma) = 42.2 +/- 19.6 GeV, with an average flux of F(gamma) = (2.31 +/- 0.13) x 10(-7) photons cm(-2) s(-1) and a power-law photon index, Gamma(gamma) = 2.13 +/- 0.02. The largest gamma-ray flaring event was observed in 2009 April-May and was accompanied by significant spectral variability above epsilon(gamma) greater than or similar to 1-2 GeV. The gamma-ray activity of NGC 1275 during this flare can be described by a hysteresis behavior in the flux versus photon index plane. The highest energy photon associated with the gamma-ray source was detected at the very end of the observation, with the observed energy of epsilon(gamma) = 67.4 GeV and an angular separation of about 2.4 arcmin from the nucleus. In this paper we present the details of the Fermi-LAT data analysis, and briefly discuss the implications of the observed gamma-ray spectral evolution of NGC 1275 in the context of gamma-ray blazar sources in general.

    DOI

  • PET装置開発研究の展望(8)APDアレー放射線検出器の開発

    鎌田圭, 遠藤貴範, 堤浩輔, 佐藤浩樹, 柳田健之, 片岡淳, 吉川彰, 高橋浩之, 薄善行

    NIRS-R (National Inst. of Radiological Sciences)   ( 61 ) 66 - 69  2010.03

    J-GLOBAL

  • 20aBP-11 Development of active shield of Hard X-ray Imager & Soft Gamma-ray Detector on ASTRO-H

    Sasaki Chikako, Kokubun Motohide, Mori Kunishiro, Kataoka Jun, Takahashi Tadayuki, Watanabe Shin, HXI SGD team

    Meeting abstracts of the Physical Society of Japan   65 ( 1 ) 103 - 103  2010.03

    CiNii

  • ASTRO‐H衛星搭載硬X線・軟ガンマ線検出器アクティブシールドの開発(I):光読み出し

    花畑義隆, 深沢泰司, 山岡和貴, 田島宏康, 片岡淳, 中澤知洋, 高橋弘充, 水野恒史, 大野雅功, 国分紀秀, 高橋忠幸, 渡辺伸, 田代信, 寺田幸功, 佐々木智香子, 中島健太, 水島翼

    日本物理学会講演概要集   65 ( 1 ) 103  2010.03

    J-GLOBAL

  • ASTRO‐H衛星搭載硬X線撮影検出器(HXI)の開発

    国分紀秀, 渡辺伸, 太田方之, 佐藤理江, 大野雅功, 田中康之, 高橋忠幸, 中澤知洋, 牧島一夫, 深沢泰司, 水野恒史, 高橋弘充, 片岡淳, 寺田幸功, 山岡和貴, 田島宏康, 田中孝明

    日本物理学会講演概要集   65 ( 1 ) 104  2010.03

    J-GLOBAL

  • Astro‐H衛星搭載軟ガンマ線検出器(SGD)の開発

    渡辺伸, 国分紀秀, 太田方之, 大野雅功, 高橋忠幸, 田島宏康, 田中孝明, 深沢泰司, 水野恒史, 高橋弘充, 中澤知洋, 片岡淳, 山岡和貴

    日本物理学会講演概要集   65 ( 1 ) 104  2010.03

    J-GLOBAL

  • ASTRO‐H衛星硬X線・軟ガンマ線検出器アクティブシールドの開発(II):機構開発

    中島健太, 中澤知洋, 西岡博之, 牧島一夫, 花畑義隆, 深沢泰司, 山崎和貴, 田島宏康, 片岡淳, 高橋弘充, 水野恒史, 大野雅功, 国分紀秀, 高橋忠幸, 渡辺伸, 田代信, 寺田幸功, 佐々木智香子, 水島翼

    日本物理学会講演概要集   65 ( 1 ) 103  2010.03

    J-GLOBAL

  • Development of wide-band X-ray gamma-ray imagers using reach-through APD arrays

    Nakamori Takeshi, Toizumi Takahiro, Yatsu Yoichi, Kawai Nobuyuki, Kataoka Jun, Ishikawa Yoshitaka, Kawai Tetsu, Kawabata Nobuyuki, Matsunaga Yusuke

      ( 9 ) 440 - 441  2010.02

     View Summary

    The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanIt is quite important to obtain wide band spectra of high energy astrophysical phenomena at the same time in order to probe emission processes or structures. Especially observations of transient objects, such as gamma-ray bursts of active galactic nuclei, expect detectors with wide energy band coverage for the sake of an efficient spectroscopy within limited time windows. An avalanche photo diode (APD) is a compact photon sensor with an internal gain of approximately 100. We have developed an X-ray / gamma-ray detector using a reach-through APD (5 × 5 sq mm) optically coupled with a conventional CsI(Tl) scintillator, which covers typically from 1 keV to 1 MeV. Further, we developed a 1-dimensional array of the 8/16 APDs (net 16 x 20) sq mm) for the purpose of an imaging photon detector combined with coded masks, to be applied in future missions. We present the current status and performances of our hybrid detector.Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science

    CiNii

  • 次期X線天文衛星ASTRO‐H(ex‐NeXT)搭載硬X線イメージャ(HXI)の開発の現状(IV)

    中澤知洋, 牧島一夫, 国分紀秀, 渡辺伸, 高橋忠幸, 深沢泰司, 片岡淳, 寺田幸功, 山岡和貴, 玉川徹, 田島宏康, OLIVIER Limousin, LAURENT Philippe, LEBRUN Francois

    日本天文学会年会講演予稿集   2010   252  2010.02

    J-GLOBAL

  • Searching for the most distant blazars with the Fermi Gamma-ray Space Telescope

    Inoue, Y, Inoue, S, Kobayashi, M. A. R, Totani, T, Kataoka, J, Sato, R

    Proceedings of the 25th Texas Symposium on Relativistic Astrophysics. December 6-10, 2010. Heidelberg, Germany. Editors: Frank M. Rieger (Chair), Christopher van Eldik and Werner Hofmann.    2010

  • Hard X-ray Imager (HXI) for the ASTRO-H mission

    M. Kokubun, K. Nakazawa, T. Enoto, Y. Fukazawa, K. Gilmore, J. Kataoka, M. Kawaharada, P. Laurent, F. Lebrun, O. Limousin, K. Makishima, T. Mizuno, K. Mori, T. Nakamori, M. Ohno, M. Ohta, G. Sato, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, Y. Terada, H. Uchiyama, Y. Uchiyama, S. Watanabe, Y. Yatsu, K. Yamaoka

    Proceedings of SPIE - The International Society for Optical Engineering   7732  2010  [Refereed]

     View Summary

    The Hard X-ray Imager (HXI) is one of four detectors on board the ASTRO-H mission (6th Japanese X-ray satellite), which is scheduled to be launched in 2014. Using the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride double-sided strip detector, the instrument fully covers the energy range of photons collected with the hard X-ray telescope up to 80 keV with a high quantum efficiency. High spatial resolution of 250 μm and an energy resolution of 1-2 keV (FWHM) are both achieved with low noise front-end ASICs. In addition, the thick BGO active shields surrounding the main detector package is a heritage of the successful performance of the Hard X-ray Detector on board the Suzaku satellite. This feature enables the instrument to achieve an extremely high background reduction caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we present the detector concept, design, latest results of the detector development, and the current status of the hardware. © 2010 SPIE.

    DOI

  • The Cosmological Evolution of Blazars and the Extragalactic Gamma-Ray Background in the Fermi Era

    Yoshiyuki Inoue, Tomonori Totani, Susumu Inoue, Masakazu A, R. Kobayashi, Jun Kataoka, Rie Sato

    2009 Fermi Symposium, Washington, D.C., Nov. 2-5, eConf Proceedings C091122    2009.12

    Article, review, commentary, editorial, etc. (international conference proceedings)  

     View Summary

    The latest determination of the extragalactic gamma-ray background (EGRB)<br />
    radiation by Fermi is compared with the theoretical prediction of the blazar<br />
    component by Inoue &amp; Totani (2009; hereafter IT09). The Fermi EGRB spectrum is<br />
    in excellent agreement with IT09, indicating that blazars are the dominant<br />
    component of the EGRB, and contributions from any other sources (e.g., dark<br />
    matter annihilations) are minor. It also indicates that the blazar SED<br />
    (spectral energy distribution) sequence taken into account in IT09 is a valid<br />
    description of mean blazar SEDs. The possible contribution of MeV blazars to<br />
    the EGRB in the MeV band is also discussed. In five total years of<br />
    observations, we predict that Fermi will detect ~1200 blazars all sky down to<br />
    the corresponding sensitivity limit. We also address the detectability of the<br />
    highest-redshift blazars. Updating our model with regard to high-redshift<br />
    evolution based on SDSS quasar data, we show that Fermi may find some blazars<br />
    up to z~6 during the five-year survey. Such blazars could provide a new probe<br />
    of early star and galaxy formation through GeV spectral attenuation signatures<br />
    induced by high-redshift UV background radiation.

  • SELENE2ローバー搭載用中性子・ガンマ線分光計 I

    長谷部信行, 鳥居祥二, 片岡淳, 唐牛譲, 山下直之, 武田侑子, 長岡央, 森田幹雄, 小林進悟, 晴山慎, 三谷烈史, 高島健, 飯島祐一, 小林正規, 荒井朋子, D’USTON Claude, KIM Kyeong Ja, BRUECKNER Johannes

    応用物理学会学術講演会講演予稿集   70th ( 1 ) 141  2009.09

    J-GLOBAL

  • 10aSD-4 Development of preamplifier of APD analog circuit for BGO readout on ASTRO-H

    Sasaki Chikako, Kokubun Motohide, Mori Kunishiro, Kataoka Jun, Sato Rie, Takahashi Tadayuki, Watanabe Shin

    Meeting abstracts of the Physical Society of Japan   64 ( 2 ) 30 - 30  2009.08

    CiNii

  • SUZAKU WIDE BAND ANALYSIS OF THE X-RAY VARIABILITY OF TeV BLAZAR Mrk 421 IN 2006

    Masayoshi Ushio, Takaaki Tanaka, Grzegorz Madejski, Tadayuki Takahashi, Masaaki Hayashida, Jun Kataoka, Daniel Mazin, Stefan Ruegamer, Rie Sato, Masahiro Teshima, Stefan Wagner, Yuichi Yaji

    ASTROPHYSICAL JOURNAL   699 ( 2 ) 1964 - 1972  2009.07

     View Summary

    We present the results of X-ray observations of the well studied TeV blazar Mrk 421 with the Suzaku satellite in 2006 April 28. During the observation, Mrk 421 was undergoing a large flare and the X-ray flux was variable, decreasing by similar to 50%, from 7.8 x 10(-10) to 3.7 x 10(-10) erg s(-1) cm(-2) in about 6 hr, followed by an increase by similar to 35%. Thanks to the broad bandpass coupled with high sensitivity of Suzaku, we measured the evolution of the spectrum over the 0.4-60 keV band in data segments as short as similar to 1 ks. The data show deviations from a simple power-law model, but also a clear spectral variability. The time-resolved spectra are fitted by a synchrotron model, where the observed spectrum is due to a exponentially cutoff power-law distribution of electrons radiating in uniform magnetic field; this model is preferred over a broken power law. As another scenario, we separate the spectrum into "steady" and "variable" components by subtracting the spectrum in the lowest-flux period from those of other data segments. In this context, the difference ("variable") spectra are all well described by a broken power-law model with photon index Gamma similar to 1.6, breaking at energy epsilon(brk) similar or equal to 3 keV to another photon index Gamma similar to 2.1 above the break energy, differing from each other only by normalization, while the spectrum of the "steady" component is best described by the synchrotron model. We suggest that the rapidly variable component is due to relatively localized shock (Fermi I) acceleration, while the slowly variable ("steady") component is due to the superposition of shocks located at larger distance along the jet, or due to other acceleration process, such as the stochastic acceleration on magnetic turbulence (Fermi II) in the more extended region.

    DOI

  • FERMI/LARGE AREA TELESCOPE BRIGHT GAMMA-RAY SOURCE LIST

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, G. F. Bignami, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, L. Costamante, S. Cutini, D. S. Davis, C. D. Dermer, A. de Angelis, A. de Luca, F. de Palma, S. W. Digel, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, D. Horan, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, D. Kocevski, M. L. Kocian, N. Komin, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, L. Poupard, S. Raino, R. Rando, P. S. Ray, M. Razzano, N. Rea, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. S. Shaw, C. Shrader, A. Sierpowska-Bartosik, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A. P. Waite, E. Wallace, P. Wang, K. Watters, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES   183 ( 1 ) 46 - 66  2009.07

     View Summary

    Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the gamma-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than similar to 10 sigma) gamma-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) gamma-ray sources in the early mission data.

    DOI

  • FERMI DISCOVERY OF GAMMA-RAY EMISSION FROM NGC 1275

    A. A. Abdo, M. Ackermann, M. Ajello, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Celotti, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L. R. Cominsky, J. Conrad, L. Costamante, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, J. Finke, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, Y. Kanai, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, F. Kuehn, M. Kuss, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, R. Sato, P. M. Saz Parkinson, C. Sgro, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. G. Thayer, D. J. Thompson, D. F. Torres, G. Tosti, Y. Uchiyama, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler, H. D. Aller, M. F. Aller, K. I. Kellermann, Y. Y. Kovalev, Yu. A. Kovalev, M. L. Lister, A. B. Pushkarev

    ASTROPHYSICAL JOURNAL   699 ( 1 ) 31 - 39  2009.07

     View Summary

    We report the discovery of high-energy (E &gt; 100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the Fermi Gamma-ray Space Telescope. The positional center of the gamma-ray source is only approximate to 3' away from the NGC 1275 nucleus, well within the 95% LAT error circle of approximate to 5'. The spatial distribution of gamma-ay photons is consistent with a point source. The average flux and power-law photon index measured with the LAT from 2008 August 4 to 2008 December 5 are F-gamma = (2.10 +/- 0.23) x 10(-7) ph (&gt;100 MeV) cm(-2) s(-1) and Gamma = 2.17 +/- 0.05, respectively. The measurements are statistically consistent with constant flux during the four-month LAT observing period. Previous EGRET observations gave an upper limit of F-gamma &lt; 3.72 x 10(-8) ph (&gt;100 MeV) cm(-2) s(-1) to the gamma-ray flux from NGC 1275. This indicates that the source is variable on timescales of years to decades, and therefore restricts the fraction of emission that can be produced in extended regions of the galaxy cluster. Contemporaneous and historical radio observations are also reported. The broadband spectrum of NGC 1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

    DOI

  • EARLY FERMI GAMMA-RAY SPACE TELESCOPE OBSERVATIONS OF THE QUASAR 3C 454.3

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, D. Donato, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, F. Rahoui, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, M. S. Shaw, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, J. A. Zensus, M. Ziegler

    ASTROPHYSICAL JOURNAL   699 ( 1 ) 817 - 823  2009.07

     View Summary

    This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable.-ray emission with an average flux of similar to 3 x 10 (6) photons cm(-2) s(-1), for energies &gt; 100 MeV. The gamma-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor delta &gt; 8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (delta similar to 25). The observed gamma-ray spectrum is not consistent with a simple power law, but instead steepens strongly above similar to 2 GeV, and is well described by a broken power law with photon indices of similar to 2.3 and similar to 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2 GeV could be due to gamma-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (less than or similar to 100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

    DOI

  • BRIGHT ACTIVE GALACTIC NUCLEI SOURCE LIST FROM THE FIRST THREE MONTHS OF THE FERMI LARGE AREA TELESCOPE ALL-SKY SURVEY

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, A. W. Chen, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, W. Collmar, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, J. Finke, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, D. Horan, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, W. McConville, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. S. Shaw, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL   700 ( 1 ) 597 - 622  2009.07

     View Summary

    The first three months of sky-survey operation with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope reveal 132 bright sources at |b| &gt; 10 degrees with test statistic greater than 100 ( corresponding to about 10 sigma). Two methods, based on the CGRaBS, CRATES, and BZCat catalogs, indicate high-confidence associations of 106 of these sources with known active galactic nuclei (AGNs). This sample is referred to as the LAT Bright AGN Sample (LBAS). It contains two radio galaxies, namely, Centaurus A and NGC 1275, and 104 blazars consisting of 58 flat spectrum radio quasars (FSRQs), 42 BL Lac objects, and 4 blazars with unknown classification. Four new blazars were discovered on the basis of the LAT detections. Remarkably, the LBAS includes 10 high-energy-peaked BL Lacs (HBLs), sources which were previously difficult to detect in the GeV range. Another 10 lower-confidence associations are found. Only 33 of the sources, plus two at |b| &lt; 10 degrees, were previously detected with Energetic Gamma-Ray Experiment Telescope( EGRET), probably due to variability. The analysis of the gamma-ray properties of the LBAS sources reveals that the average GeV spectra of BL Lac objects are significantly harder than the spectra of FSRQs. No significant correlation between radio and peak gamma-ray fluxes is observed. Blazar log N-log S distributions and luminosity functions are constructed to investigate the evolution of the different blazar classes, with positive evolution indicated for FSRQs but none for BL Lacs. The contribution of LAT blazars to the total extragalactic gamma-ray intensity is estimated.

    DOI

  • Performance of a multi-anode photomultiplier employing an ultra bi-alkali photo-cathode and rugged dynodes

    T. Toizumi, S. Inagawa, T. Nakamori, J. Kataoka, Y. Tsubuku, Y. Yatsu, T. Shimokawabe, N. Kawai, T. Okada, I. Ohtsu

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 168 - 173  2009.06

     View Summary

    We report on the performance testing of a multi-anode photomultiplier (MAPMT), the R8900-200-M16MOD-UBA, newly developed by Hamamatsu Photonics K.K. Although the R8900 series offers the great advantage of a highly sensitive surface (&gt;=-80% of physical area), the quantum efficiency (Q.E.) was relatively low (at up to 20%). This paper describes two substantial changes we have made to the R8900-200-M16MOD-UBA: (1) improving the Q.E. to the 40% level by employing an ultra bi-alkali (UBA) photocathode and (2) constructing a rugged dynode that can withstand vibration for future use in space. We measured each pixel signal at the single photoelectron level and the signals of scintillation photons by using a 16-pixel plastic scintillator array. Thanks to high Q.E., good energy resolution of 29.9% (FWHM) was obtained for 59.5 keV gamma-rays. We also demonstrated tolerance to vibration up to 17 G(rms) in possible launching vehicles. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • Development of a low-noise analog front-end ASIC for APD-PET detectors

    M. Koizumi, J. Kataoka, S. Tanaka, H. Ishibashi, N. Kawai, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, K. Shimizu, H. Kubo

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 327 - 330  2009.06

     View Summary

    We report on the development of a front-end ASIC for high spatial resolution PET detectors with time-of-flight capability based on LYSO scintillator arrays coupled with position-sensitive avalanche photodiode (APD) arrays. The ASIC is designed based on the open-IP LSI project led by JAXA and realized in TSMC 0.35-mu m CMOS technology. It consists of an 8-channel charge-sensitive amplifier, band-pass filters, differentiators, pulse-height and timing discriminators, and two-channel time-to-amplitude converters. As a result, energy resolution of 9.7% (FWHM) is obtained at 511 keV, with a time resolution below 970 ps (sigma). We will also report on the current status of developing a second-version ASIC designed to have 32-channel analog circuits with improved time resolution. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • Development of large-area, reverse-type APD-arrays for high-resolution medical imaging

    J. Kataoka, M. Koizumi, S. Tanaka, H. Ishibashi, T. Nakamori, N. Kawai, H. Ikeda, Y. Ishikawa, N. Kawabata, Y. Matsunaga, S. Kishimoto, H. Kubo

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   604 ( 1-2 ) 323 - 326  2009.06

     View Summary

    Avalanche photodiodes (APD) offer advantages in terms of weak scintillation detection, fast time response, and magnetic field insensitivity. We have developed new types of large-area, reverse-type APD-arrays specifically designed for high-resolution positron emission tomography (PET). Each device has a monolithic 16 x 16 (or 8 x 8) pixel structure with an active area of 1.0 (or 4.0, 0.25) mm(2) for each pixel. An excellent gain uniformity (&lt;= 10%) and low dark noise (&lt;= 0.3 nA) have been achieved, measured at room temperature. Energy resolution of 7.2% (FWHM) was obtained for the direct detection of 5.9 keV X-rays, while 10.2% (FWHM) was obtained for 662 keV gamma-rays when coupled with a LYSO scintillator matrix. An excellent time resolution of 102 ps (FWHM) was obtained for a monolithic, 3 mm phi APD pixel. These results suggest that APD-arrays could be a promising device for future applications in nuclear medicine. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM: SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE

    F. Aharonian, A. G. Akhperjanian, G. Anton, U. Barres de Almeida, A. R. Bazer-Bachi, Y. Becherini, B. Behera, K. Bernloehr, C. Boisson, A. Bochow, V. Borrel, E. Brion, J. Brucker, P. Brun, R. Buehler, T. Bulik, I. Buesching, T. Boutelier, P. M. Chadwick, A. Charbonnier, R. C. G. Chaves, A. Cheesebrough, L. M. Chounet, A. C. Clapson, G. Coignet, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Atai, W. Domainko, L. O. C. Drury, F. Dubois, G. Dubus, J. Dyks, M. Dyrda, K. Egberts, D. Emmanoulopoulos, P. Espigat, C. Farnier, F. Feinstein, F. Fiasson, A. Foerster, G. Fontaine, M. Fuessling, S. Gabici, Y. A. Gallant, L. Gerard, B. Giebels, J. F. Glicenstein, B. Glueck, P. Goret, D. Goehring, D. Hauser, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, M. Holleran, S. Hoppe, D. Horns, A. Jacholkowska, O. C. de Jager, C. Jahn, I. Jung, K. Katarzynski, U. Katz, S. Kaufmann, E. Kendziorra, M. Kerschhaggl, D. Khangulyan, B. Khelifi, D. Keogh, W. Kluzniak, N. Komin, K. Kosack, G. Lamanna, J.-P. Lenain, T. Lohse, V. Marandon, J. M. Martin, O. Martineau-Huynh, A. Marcowith, D. Maurin, T. J. L. McComb, M. C. Medina, R. Moderski, E. Moulin, M. Naumann-Godo, M. de Naurois, D. Nedbal, D. Nekrassov, J. Niemiec, S. J. Nolan, S. Ohm, J.-F. Olive, E. de Ona Wilhelmi, K. J. Orford, M. Ostrowski, M. Panter, M. Paz Arribas, G. Pedaletti, G. Pelletier, P.-O. Petrucci, S. Pita, G. Puehlhofer, M. Punch, A. Quirrenbach, B. C. Raubenheimer, M. Raue, S. M. Rayner, M. Renaud, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. RudaK, C. B. Rulten, J. Ruppel, V. Sahakian, A. Santangelo, R. Schlickeiser, F. M. Schoeck, R. Schroeder, U. Schwanke, S. Schwarzburg, S. Schwemmer, A. Shalchi, M. Sikora, J. L. Skilton, H. Sol, D. Spangler, L. Stawarz, R. Steenkamp, C. Stegmann, G. Superina, A. Szostek, P. H. Tam, J.-P. Tavernet, R. Terrier, O. Tibolla, C. van Eldik, G. Vasileiadis, C. Venter, L. Venter, J. P. Vialle, P. Vincent, M. Vivier, H. J. Voelk, F. Volpe, S. J. Wagner, M. Ward, A. A. Zdziarski, A. Zech, A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, A. W. Chen, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, R. Dubois, G. Dubus, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M.-H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, D. Horan, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knodlseder, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, F. Ryde, H. F.-W. Sadrozinski, D. Sanchez, A. Sander, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. Shaw, D. A. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. S. Strickman, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL LETTERS   696 ( 2 ) L150 - L155  2009.05

     View Summary

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of gamma-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; &gt; 100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little (similar to 30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

    DOI

  • SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM: SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE

    F. Aharonian, A. G. Akhperjanian, G. Anton, U. Barres de Almeida, A. R. Bazer-Bachi, Y. Becherini, B. Behera, K. Bernloehr, C. Boisson, A. Bochow, V. Borrel, E. Brion, J. Brucker, P. Brun, R. Buehler, T. Bulik, I. Buesching, T. Boutelier, P. M. Chadwick, A. Charbonnier, R. C. G. Chaves, A. Cheesebrough, L. M. Chounet, A. C. Clapson, G. Coignet, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Atai, W. Domainko, L. O. C. Drury, F. Dubois, G. Dubus, J. Dyks, M. Dyrda, K. Egberts, D. Emmanoulopoulos, P. Espigat, C. Farnier, F. Feinstein, F. Fiasson, A. Foerster, G. Fontaine, M. Fuessling, S. Gabici, Y. A. Gallant, L. Gerard, B. Giebels, J. F. Glicenstein, B. Glueck, P. Goret, D. Goehring, D. Hauser, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, M. Holleran, S. Hoppe, D. Horns, A. Jacholkowska, O. C. de Jager, C. Jahn, I. Jung, K. Katarzynski, U. Katz, S. Kaufmann, E. Kendziorra, M. Kerschhaggl, D. Khangulyan, B. Khelifi, D. Keogh, W. Kluzniak, N. Komin, K. Kosack, G. Lamanna, J.-P. Lenain, T. Lohse, V. Marandon, J. M. Martin, O. Martineau-Huynh, A. Marcowith, D. Maurin, T. J. L. McComb, M. C. Medina, R. Moderski, E. Moulin, M. Naumann-Godo, M. de Naurois, D. Nedbal, D. Nekrassov, J. Niemiec, S. J. Nolan, S. Ohm, J.-F. Olive, E. de Ona Wilhelmi, K. J. Orford, M. Ostrowski, M. Panter, M. Paz Arribas, G. Pedaletti, G. Pelletier, P.-O. Petrucci, S. Pita, G. Puehlhofer, M. Punch, A. Quirrenbach, B. C. Raubenheimer, M. Raue, S. M. Rayner, M. Renaud, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. RudaK, C. B. Rulten, J. Ruppel, V. Sahakian, A. Santangelo, R. Schlickeiser, F. M. Schoeck, R. Schroeder, U. Schwanke, S. Schwarzburg, S. Schwemmer, A. Shalchi, M. Sikora, J. L. Skilton, H. Sol, D. Spangler, L. Stawarz, R. Steenkamp, C. Stegmann, G. Superina, A. Szostek, P. H. Tam, J.-P. Tavernet, R. Terrier, O. Tibolla, C. van Eldik, G. Vasileiadis, C. Venter, L. Venter, J. P. Vialle, P. Vincent, M. Vivier, H. J. Voelk, F. Volpe, S. J. Wagner, M. Ward, A. A. Zdziarski, A. Zech, A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, A. W. Chen, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, R. Dubois, G. Dubus, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M.-H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, D. Horan, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knodlseder, F. Kuehn, M. Kuss, J. Lande, L. Latronico, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, F. Ryde, H. F.-W. Sadrozinski, D. Sanchez, A. Sander, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, M. Shaw, D. A. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. S. Strickman, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL LETTERS   696 ( 2 ) L150 - L155  2009.05

     View Summary

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of gamma-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; &gt; 100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little (similar to 30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

    DOI

  • Measurement of the Cosmic Ray e(+)+e(-) Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope

    A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, G. Bogaert, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, P. Carlson, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, G. Di Bernardo, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, D. Gaggero, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, D. Grasso, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, D. Kocevski, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. M. Massai, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, M. Pohl, T. A. Porter, S. Profumo, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, A. Sellerholm, C. Sgro, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, V. Vasileiou, N. Vilchez, V. Vitale, A. P. Waite, E. Wallace, P. Wang, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    PHYSICAL REVIEW LETTERS   102 ( 18 ) 1101  2009.05

     View Summary

    Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m(2) sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E-3.0 and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.

    DOI

  • FERMI/LARGE AREA TELESCOPE DISCOVERY OF GAMMA-RAY EMISSION FROM THE FLAT-SPECTRUM RADIO QUASAR PKS 1454-354

    A. A. Abdo, M. Ackermann, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, G. Bogaert, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, E. C. Ferrara, P. Fleury, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, S. E. Healey, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, M. L. Kocian, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. Marelli, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, M. Ohno, T. Ohsugi, R. Ojha, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, M. S. Shaw, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler, P. G. Edwards, M. M. Chester, D. N. Burrows, M. Hauser, S. Wagner

    ASTROPHYSICAL JOURNAL   697 ( 1 ) 934 - 941  2009.05

     View Summary

    We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy gamma-ray (GeV) emission from the flat-spectrum radio quasar PKS 1454-354 (z = 1.424). On 2008 September 4, the source rose to a peak flux of (3.5 +/- 0.7) x 10(-6) ph cm(-2) s(-1) (E &gt; 100 MeV) on a timescale of hours and then slowly dropped over the following 2 days. No significant spectral changes occurred during the flare. Fermi/LAT observations also showed that PKS 1454-354 is the most probable counterpart of the unidentified EGRET source 3EG J1500-3509. Multiwavelength measurements performed during the following days (7 September with Swift; 6-7 September with the ground-based optical telescope Automated Telescope for Optical Monitoring; 13 September with the Australia Telescope Compact Array) resulted in radio, optical, UV, and X-ray fluxes greater than archival data, confirming the activity of PKS 1454-354.

    DOI

  • FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE VELA PULSAR

    A. A. Abdo, M. Ackermann, W. B. Atwood, R. Bagagli, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, M. G. Baring, J. Bartelt, D. Bastieri, B. M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, B. Berenji, D. Bisello, R. D. Blandford, E. D. Bloom, J. R. Bogart, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, M. Ceccanti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, L. Corucci, S. Cutini, D. S. Davis, M. DeKlotz, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, D. L. Flath, P. Fleury, W. B. Focke, M. Frailis, P. C. C. Friere, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, R. Giannitrapani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, G. Haller, A. K. Harding, P. A. Hart, R. C. Hartman, E. Hays, G. Hobbs, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, G. Kanbach, V. M. Kaspi, H. Katagiri, J. Kataoka, A. Kavelaars, N. Kawai, H. Kelly, M. Kerr, B. Kiziltan, W. Klamra, J. Knodlseder, M. Kramer, F. Kuehn, M. Kuss, J. Lande, D. Landriu, L. Latronico, B. Lee, S. -H. Lee, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. G. Lyne, G. M. Madejski, A. Makeev, R. N. Manchester, B. Marangelli, M. Marelli, M. N. Mazziotta, J. E. McEnery, S. McGlynn, M. A. McLaughlin, N. Menon, C. Meurer, P. F. Michelson, T. Mineo, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. Mongelli, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, A. Paccagnella, D. Paneque, J. H. Panetta, D. Parent, M. Pearce, M. Pepe, M. Perchiazzi, M. Pesce-Rollins, L. Pieri, M. Pinchera, F. Piron, T. A. Porter, S. Raino, R. Rando, S. M. Ransom, E. Rapposelli, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, A. Sacchetti, H. F. -W. Sadrozinski, N. Saggini, D. Sanchez, A. Sander, P. M. Saz Parkinson, K. N. Segal, A. Sellerholm, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, J. -L. Starck, F. W. Stecker, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J. B. Thayer, J. G. Thayer, G. Theureau, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, D. F. Torres, A. Tramacere, M. Turri, T. L. Usher, L. Vigiani, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, K. Watters, P. Weltevrede, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

    ASTROPHYSICAL JOURNAL   696 ( 2 ) 1084 - 1093  2009.05

     View Summary

    The Vela pulsar is the brightest persistent source in the GeV sky and thus is the traditional first target for new gamma-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure and early sky survey scanning. We have used the Vela signal to verify Fermi timing and angular resolution. The high-quality pulse profile, with some 32,400 pulsed photons at E &gt;= 0.03 GeV, shows new features, including pulse structure as fine as 0.3 ms and a distinct third peak, which shifts in phase with energy. We examine the high-energy behavior of the pulsed emission; initial spectra suggest a phase-averaged power-law index of Gamma = 1.51(-0.04)(+0.05) with an exponential cutoff at E-c = 2.9 +/- 0.1 GeV. Spectral fits with generalized cutoffs of the form e(-(E/Ec)b) require b &lt;= 1, which is inconsistent with magnetic pair attenuation, and thus favor outer-magnetosphere emission models. Finally, we report on upper limits to any unpulsed component, as might be associated with a surrounding pulsar wind nebula.

    DOI

  • DISCOVERY OF PULSED gamma-RAYS FROM THE YOUNG RADIO PULSAR PSR J1028-5819 WITH THE FERMI LARGE AREA TELESCOPE

    A. A. Abdo, M. Ackermann, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, N. Komin, M. Kramer, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, S. E. Thorsett, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A. P. Waite, K. Watters, K. S. Wood, T. Ylinen, M. Ziegler, G. Hobbs, M. Keith, R. N. Manchester, P. Weltevrede

    ASTROPHYSICAL JOURNAL LETTERS   695 ( 1 ) L72 - L77  2009.04

     View Summary

    Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz) in the error circle of the Energetic Gamma-Ray Experiment Telescope (EGRET) source 3EG J1027-5817. The spin-down power of this young pulsar is great enough to make it very likely the counterpart for the EGRET source. We report here the discovery of gamma-ray pulsations from PSR J1028-5819 in early observations by the Large Area Telescope (LAT) on the Fermi Gamma-Ray Space Telescope. The gamma-ray light curve shows two sharp peaks having phase separation of 0.460 +/- 0.004, trailing the very narrow radio pulse by 0.200 +/- 0.003 in phase, very similar to that of other known gamma-ray pulsars. The measured gamma-ray flux gives an efficiency for the pulsar of similar to 10-20% (for outer magnetosphere beam models). No evidence of a surrounding pulsar wind nebula is seen in the current Fermi data but limits on associated emission are weak because the source lies in a crowded region with high background emission. However, the improved angular resolution afforded by the LAT enables the disentanglement of the previous COS-B and EGRET source detections into at least two distinct sources, one of which is now identified as PSR J1028-5819.

    DOI

  • DISCOVERY OF PULSED gamma-RAYS FROM THE YOUNG RADIO PULSAR PSR J1028-5819 WITH THE FERMI LARGE AREA TELESCOPE

    A. A. Abdo, M. Ackermann, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, M. Dormody, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, C. Farnier, C. Favuzzi, P. Fleury, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knoedlseder, N. Komin, M. Kramer, F. Kuehn, M. Kuss, L. Latronico, S. -H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. Marelli, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. -L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, S. E. Thorsett, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, A. Van Etten, N. Vilchez, V. Vitale, A. P. Waite, K. Watters, K. S. Wood, T. Ylinen, M. Ziegler, G. Hobbs, M. Keith, R. N. Manchester, P. Weltevrede

    ASTROPHYSICAL JOURNAL LETTERS   695 ( 1 ) L72 - L77  2009.04

     View Summary

    Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz) in the error circle of the Energetic Gamma-Ray Experiment Telescope (EGRET) source 3EG J1027-5817. The spin-down power of this young pulsar is great enough to make it very likely the counterpart for the EGRET source. We report here the discovery of gamma-ray pulsations from PSR J1028-5819 in early observations by the Large Area Telescope (LAT) on the Fermi Gamma-Ray Space Telescope. The gamma-ray light curve shows two sharp peaks having phase separation of 0.460 +/- 0.004, trailing the very narrow radio pulse by 0.200 +/- 0.003 in phase, very similar to that of other known gamma-ray pulsars. The measured gamma-ray flux gives an efficiency for the pulsar of similar to 10-20% (for outer magnetosphere beam models). No evidence of a surrounding pulsar wind nebula is seen in the current Fermi data but limits on associated emission are weak because the source lies in a crowded region with high background emission. However, the improved angular resolution afforded by the LAT enables the disentanglement of the previous COS-B and EGRET source detections into at least two distinct sources, one of which is now identified as PSR J1028-5819.

    DOI

  • 28pSH-4 MAXI (Monitor of All-Sky X-ray Image) Data Analysis Sotware and Reduction System

    Sugizaki M., Mihara T., Isobe N., Matsuoka M., Kawasaki K., Ueno S., Tomida H., Kohama M., Suzuki M., Ishikawa M., Adachi Y., Tsunemi H., Miyata E., Kawai N., Kataoka J., Yoshida A., Yamaoka K., Negoro H., Nakajima M., Ueda Y., Morii M.

    Meeting abstracts of the Physical Society of Japan   64 ( 1 ) 92 - 92  2009.03

    CiNii

  • 27aXD-10 Galactic diffuse gamma-rays observed by Fermi LAT

    Mizuno Tsunefumi, Digel Seth, Fermi LAT Colaboration

    Meeting abstracts of the Physical Society of Japan   64 ( 1 ) 87 - 87  2009.03

    CiNii

  • SUZAKU OBSERVATIONS OF THE EXTREME MeV BLAZAR SWIFT J0746.3+2548

    Shin Watanabe, Rie Sato, Tadayuki Takahashi, Jun Kataoka, Greg Madejski, Marek Sikora, Fabrizio Tavecchio, Rita Sambruna, Roger Romani, Philip G. Edwards, Tapio Pursimo

    ASTROPHYSICAL JOURNAL   694 ( 1 ) 294 - 301  2009.03

     View Summary

    We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in 2005 November. This object, which, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics and high signal-to-noise ratio spectrum, the Suzaku observation clearly confirms that J0746 has an extremely hard spectrum in the energy range of 0.3-24 keV, which is well represented by a single power-law with a photon index of Gamma(ph) similar or equal to 1.17 and Galactic absorption. The multiwavelength spectral energy distribution of J0746 shows two continuum components, and is well modeled assuming that the high-energy spectral component results from Comptonization of the broad-line region photons. In this paper, we search for the bulk Compton spectral features predicted to be produced in the soft X-ray band by scattering external optical/UV photons by cold electrons in a relativistic jet. We discuss and provide constraints on the pair content resulting from the apparent absence of such features.

    DOI

  • Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    A. A. Abdo, M. Ackermann, M. Arimoto, K. Asano, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, M. G. Baring, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, B. Berenji, P. N. Bhat, E. Bissaldi, R. D. Blandford, E. D. Bloom, G. Bogaert, J. R. Bogart, E. Bonamente, J. Bonnell, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. S. Briggs, M. Brigida, P. Bruel, T. H. Burnett, D. Burrows, G. Busetto, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, M. Ceccanti, C. Cecchi, A. Celotti, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, V. Connaughton, J. Conrad, L. Costamante, S. Cutini, M. DeKlotz, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, B. L. Dingus, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, Y. Edmonds, P. A. Evans, D. Fabiani, C. Farnier, C. Favuzzi, J. Finke, G. Fishman, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, A. Goldstein, J. Granot, J. Greiner, I. A. Grenier, M. -H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, G. Haller, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, J. A. Hernando Morata, A. Hoover, R. E. Hughes, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, A. Kavelaars, N. Kawai, H. Kelly, J. Kennea, M. Kerr, R. M. Kippen, J. Knoedlseder, D. Kocevski, M. L. Kocian, N. Komin, C. Kouveliotou, F. Kuehn, M. Kuss, J. Lande, D. Landriu, S. Larsson, L. Latronico, C. Lavalley, B. Lee, S. -H. Lee, M. Lemoine-Goumard, G. G. Lichti, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, B. Marangelli, M. N. Mazziotta, S. McBreen, J. E. McEnery, S. McGlynn, C. Meegan, P. Meszaros, C. Meurer, P. F. Michelson, M. Minuti, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, D. Nelson, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, W. S. Paciesas, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Perri, M. Pesce-Rollins, V. Petrosian, M. Pinchera, F. Piron, T. A. Porter, R. Preece, S. Raino, E. Ramirez-Ruiz, R. Rando, E. Rapposelli, M. Razzano, S. Razzaque, N. Rea, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, M. Roth, F. Ryde, H. F. -W. Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, K. N. Segal, C. Sgro, T. Shimokawabe, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, J. -L. Starck, F. W. Stecker, H. Steinle, T. E. Stephens, M. S. Strickman, D. J. Suson, G. Tagliaferri, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, M. Turri, S. Tuvi, T. L. Usher, A. J. van der Horst, L. Vigiani, N. Vilchez, V. Vitale, A. von Kienlin, A. P. Waite, D. A. Williams, C. Wilson-Hodge, B. L. Winer, K. S. Wood, X. F. Wu, R. Yamazaki, T. Ylinen, M. Ziegler

    SCIENCE   323 ( 5922 ) 1688 - 1693  2009.03

     View Summary

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gamma-ray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

    DOI PubMed CiNii

  • 次期X線天文衛星ASTRO‐H(ex‐NeXT)搭載硬X線イメージャ(HXI)の開発の現状(III)

    中澤知洋, 牧島一夫, 国分紀秀, 渡辺伸, 高橋忠幸, 深沢泰司, 片岡淳, 寺田幸功, 山岡和貴, 玉川徹, 田島宏康

    日本天文学会年会講演予稿集   2009   260  2009.02

    J-GLOBAL

  • フェルミ・ガンマ線宇宙望遠鏡によるPWN候補の銀河系内TeVガンマ線源の観測

    中森健之, 金井義和, 下川辺隆史, 有元誠, 片岡淳, 河合誠之, 高橋弘充, 山崎了, 片桐秀明, 水野恒史, 深沢泰司, 大杉節, 大野雅功, 佐藤理江, 尾崎正伸, 高橋忠幸, 田中孝明, 林田将明, 内山泰伸, 田島宏康, 釜江常好, FUNK S., GRONDIN M., LEMOINE-GOUMARD M., MAZZIOTTA N.

    日本天文学会年会講演予稿集   2009  2009

    J-GLOBAL

  • Fermiガンマ線宇宙望遠鏡によって検出されたパルサー

    河合誠之, 金井義和, 片岡淳, 下川辺隆史, 中森健之, 大杉節, 深沢泰司, 水野恒史, 高橋弘充, 片桐秀明, 高橋忠幸, 尾崎正伸, 田島宏康, 釜江常好, REIMER O., ROMANI R., ATWOOD W., ZIEGLER M., PARKINSON P., WOOD K., ABDO A., HARDING A., THOMPSON D., CHEUNG T., JOHNSON T., CALIANDRO A., RAZZANO M., SMITH D., GUILLEMOT L., KERR M., KANBACH G., TIBOLLA O., BALLET J., GRENIER I.

    日本天文学会年会講演予稿集   2009  2009

    J-GLOBAL

  • MITSuME望遠鏡によるブレーザーの長期モニター観測

    森由希, 片岡淳, 河合誠之, 下川辺隆史, 工藤佑允, 中嶋英也, 佐藤理江, 高橋忠幸, MADEJSKI G.

    日本天文学会年会講演予稿集   2009  2009

    J-GLOBAL

  • Fermi衛星で探る高赤方偏移GeVガンマ線ブレーザー天体:宇宙再電離,UV背景放射の解明に向けて

    井上芳幸, 井上進, 小林正和, 戸谷友則, 片岡淳, 佐藤理江

    日本天文学会年会講演予稿集   2009  2009

    J-GLOBAL

  • PoGOLite: A balloon-borne soft gamma-ray polarimeter

    M. Jackson, M. Pearce, H. Takahashi, M. Axelsson, H.-G. Florén, Y. Fukazawa, S. Gunji, T. Kamae, Y. Kanai, J. Kataoka, N. Kawai, M. Kiss, W. Klamra, S. Larsson, G. Madejski, K. Maeda, P. Mallol, C. Marini Bettolo, Y. Miyamoto, T. Mizuno, G. Olofsson, F. Ryde, S. Rydström, J.-E. Strömberg, H. Tajima, T. Takahashi, T. Tanaka, T. Thurston, G. Varner, H. Yoshida, M. Pearce

    IEEE Nuclear Science Symposium Conference Record   2 ( OG PART 1 ) 449 - 453  2009  [Refereed]

     View Summary

    PoGOLite is a balloon-borne X-ray polarimeter, designed to measure the polarization of 25-80 keV X-rays. It is scheduled for a pathfinder flight in August 2010. This paper outlines the scientific motivation and the status of preparations of the payload. ©2009 IEEE.

    DOI

  • SELENE2ローバー搭載用中性子・ガンマ線分光計

    長谷部信行, 鳥居祥二, 片岡淳, 唐牛譲, 山下直之, 武田侑子, 森田幹雄, 小林進悟, 晴山慎, 三谷烈史, 高島健, 小林正規, 荒井朋子, D’USTON Claude, KIM Kyeong Ja, BRUECKNER Johannes

    宇宙科学技術連合講演会講演集(CD-ROM)   53rd   1J02  2009

    J-GLOBAL

  • SELENE2ローバ搭載用ガンマ線・中性子分光計

    森田幹雄, 長谷部信行, 鳥居祥二, 片岡淳, 唐牛譲, 早津佳那子, 武田侑子, 長岡央, 三谷烈史, 小林進悟, 晴山慎, 飯島祐一, 高島健, 小林正規, 荒井朋子, D’USTON C, GASNAULT O, 山下直之, KIM K. J, DOHM J. M

    太陽系科学シンポジウム講演集録(CD-ROM)   31st   ROMBUNNO.12GATSU21NICHI,14  2009

    J-GLOBAL

  • Suzaku observation of TeV blazar the 1ES 1218+304: clues on particle acceleration in an extreme TeV blazar

    R. Sato, J. Kataoka, T. Takahashi, G. M. Medejski, S. Ruegamer, S. J. Wagner

    HIGH ENERGY GAMMA-RAY ASTRONOMY   1085   447 - +  2009

     View Summary

    We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of similar to 2 on a timescale of 5 x 10(4) s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft X-rays, with the maximum lag of 2.3X10(4) s observed between the 0.3-1 keV and 5-10 keV bands, Furthermore we discovered that the temporal profile of the flare clearly changes with energy, being more symmetric at higher energies. From the spectral fitting of multi-wavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B similar to 0.047 G, an emission region size R = 3.0 x 10(16) cm for an appropriate beaming with a Doppler factor of delta = 20. This value of B is in good agreement with an independent estimate through the model fit to the observed time lag ascribing the energy-dependent variability to differential acceleration timescale of relativistic electrons provided that the gyro-factor xi is 10(5).

    DOI

  • Suzaku observation of TeV blazar the 1ES 1218+304: clues on particle acceleration in an extreme TeV blazar

    R. Sato, J. Kataoka, T. Takahashi, G. M. Medejski, S. Ruegamer, S. J. Wagner

    HIGH ENERGY GAMMA-RAY ASTRONOMY   1085   447 - +  2009

     View Summary

    We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of similar to 2 on a timescale of 5 x 10(4) s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft X-rays, with the maximum lag of 2.3X10(4) s observed between the 0.3-1 keV and 5-10 keV bands, Furthermore we discovered that the temporal profile of the flare clearly changes with energy, being more symmetric at higher energies. From the spectral fitting of multi-wavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B similar to 0.047 G, an emission region size R = 3.0 x 10(16) cm for an appropriate beaming with a Doppler factor of delta = 20. This value of B is in good agreement with an independent estimate through the model fit to the observed time lag ascribing the energy-dependent variability to differential acceleration timescale of relativistic electrons provided that the gyro-factor xi is 10(5).

    DOI

  • Suzaku Observations of Tycho's Supernova Remnant

    Toru Tamagawa, Asami Hayato, Satoshi Nakamura, Yukikatsu Terada, Aya Bamba, Junko S. Hiraga, John P. Hughes, Una Hwang, Jun Kataoka, Kenzo Kinugasa, Hideyo Kunieda, Takaaki Tanaka, Hiroshi Tsunemi, Masaru Ueno, Stephen S. Holt, Motohide Kokubun, Emi Miyata, Andrew Szymkowiak, Tadayuki Takahashi, Keisuke Tamura, Daisuke Ueno, Kazuo Makishima

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   61   S167 - S174  2009.01

     View Summary

    Tycho's supernova remnant was observed by the XIS and HXD instruments onboard the Suzaku satellite on 2006 June 26-29 for 92 ks. The spectrum up to 30 keV was well fitted with a two-component model, consisting of a power-law with a photon index of 2.7 and a thermal bremsstrahlung model with a temperature of 4.7 keV. The former component can alternatively be modeled as synchrotron emission from a population of relativistic electrons with an estimated roll-off energy of around 1 keV. In the XIS spectra, in addition to the prominent Fe K alpha line (6.445 keV), we observed for the first time significant K alpha line emission from trace species Cr and Mn at energies of 5.48 keV and 5.95 keV, respectively. Faint K beta lines from Ca (4.56 keV) and Fe (7.11 keV) were also seen. The ionization states of Cr and Mn, based on their line centroids, Lire estimated to be similar to that of Fe K alpha (Fe XV or XVI).

    DOI

  • Study of nonthermal emission from SNR RX J1713.7-3946 with Suzaku

    Takaaki Tanaka, Yasunobu Uchiyama, Felix A. Aharonian, Tadayuki Takahashi, Aya Bamba, Junko S. Hiraga, Jun Kataoka, Tetsuichi Kishishita, Motohide Kokubun, Koji Mori, Kazuhiro Nakazawa, Robert Petre, Hiroyasu Tajima, Shin Watanabe

    ASTROPHYSICAL JOURNAL   685 ( 2 ) 988 - 1004  2008.10

     View Summary

    We present results obtained from a series of observations of the supernova remnant RX J1713.7-3946 by Suzaku. Hard X-rays have been detected up to similar to 40 keV. The hard X-ray spectra are described by a power law with photon indices of similar to 3.0, which is larger than those below 10 keV. The combination of the spatially integrated XIS and HXD spectra clearly reveals a spectral cutoff which is linked to the maximum energy of accelerated electrons. The broad-band coverage of Suzaku allows us to derive, for the first time, the energy spectrum of parent electrons in the cutoff region. The cutoff energy in the X-ray spectrum indicates that the electron acceleration in the remnant proceeds close to the Bohm diffusion limit. We discuss the implications of the spectral and morphological properties of the Suzaku data in the context of the origin of nonthermal emission. The Suzaku X-ray and H.E.S.S. gamma-ray data together hardly can be explained within a pure leptonic scenario. Moreover, the leptonic models require a weak magnetic field, which is inconsistent with the recently discovered X-ray filamentary structures and their short-term variability. The hadronic models with strong magnetic fields provide reasonable fits to the observed spectra, but require special arrangements of parameters to explain the lack of thermal X-ray emission. For morphology studies, we compare the X-ray and TeV gamma-ray surface brightness. We confirm the previously reported strong correlation between X-rays and TeV gamma rays. At the same time, the Suzaku data reveal a deviation from the general tendency, namely, the X-ray emission in the western rims appears brighter than expected from the average X-ray to gamma-ray ratio.

    DOI

  • Chandra reveals twin X-ray jets in the powerful FR II radio galaxy 3C 353

    J. Kataoka, L. Stawarz, D. E. Harris, A. Siemiginowska, M. Ostrowski, M. R. Swain, M. J. Hardcastle, J. L. Goodger, K. Iwasawa, P. G. Edwards

    ASTROPHYSICAL JOURNAL   685 ( 2 ) 839 - 857  2008.10

     View Summary

    We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-Ray Observatory. Due to 3C 353's two 4 '' wide and 2' long jets we are able to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the subarcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the jet and the counterjet, the terminal jet regions (hot spots), and one radio lobe. We show that the detection of the X-ray emission associated with the radio knots and counterknots, which is most likely nonthermal in origin, puts several crucial constraints on the X-ray emission mechanisms in powerful large-scale jets of quasars and FR II sources. In particular, we show that this detection is inconsistent with the inverse-Compton model proposed in the literature and instead implies a synchrotron origin of the X-ray jet photons. We also find that the width of the X-ray counterjet is possibly narrower than that measured in radio bands, that the radio to X-ray flux ratio decreases systematically downstream along the jets, and that there are substantial (kpc-scale) offsets between the positions of the X-ray and radio intensity maxima within each knot, whose magnitudes increase away from the nucleus. We discuss all these findings in the wider context of the physics of extragalactic jets, proposing some particular although not definitive solutions or interpretations for each problem. In general, we find that the synchrotron X-ray emission of extragalactic large-scale jets is not only shaped by the global hydrodynamical configuration of the outflows, but is also likely to be very sensitive to the microscopic parameters of the jet plasma. A complete, self-consistent model for the X-ray emission of extragalactic jets still remains elusive.

    DOI

  • PoGOLite - A high sensitivity balloon-borne soft gamma-ray polarimeter

    Tuneyoshi Kamae, Viktor Andersson, Makoto Arimoto, Magnus Axelsson, Cecilia Marini Bettolo, Claes-Ingvar Bjornsson, Gilles Bogaert, Per Carlson, William Craig, Tomas Ekeberg, Olle Engdegdrd, Yasushi Fukazawa, Shuichi Gunji, Linnea Hjalmarsdotter, Bianca Iwan, Yoshikazu Kanai, Jun Kataoka, Nobuyuki Kawai, Jaroslav Kazejev, Mozsi Kiss, Wlodzimierz Klamra, Stefan Larsson, Grzegorz Madejski, Tsunefumi Mizuno, Johnny Ng, Mark Pearce, Felix Ryde, Markus Suhonen, Hiroyasu TaJima, Hiromitsu Takahashi, Tadayuki Takahashi, Takuya Tanaka, Timothy Thurston, Masaru Ueno, Gary Varneri, Kazuhide Yamamoto, Yuichiro Yamashita, Tomi Ylinen, Hiroaki Yoshida

    ASTROPARTICLE PHYSICS   30 ( 2 ) 72 - 84  2008.09

     View Summary

    We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200 mCrab point-like sources between 25 and 80 keV in one 6-h flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. Synchrotron radiation, inverse Compton scattering and propagation through high magnetic fields are likely to produce high degrees of polarisation in the energy band of the instrument. We demonstrate, through tests at accelerators, with radioactive sources and through computer simulations, that PoGOLite will be able to detect degrees of polarisation as predicted by models for several classes of high energy sources. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles while securing a large effective area has been the greatest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow Held of view (FWHM = 1.25 msr, 2.0 deg x 2.0 deg) obtained with detector cells and the use of thick background shields warrant a large effective area for polarisation measurements (similar to 228 cm(2) at E = 40 keV) without sacrificing the signal-to-noise ratio. Simulation studies for an atmospheric overburden of 3-4 g/cm(2) indicate that neutrons and gamma-rays entering the PDC assembly through the shields are dominant backgrounds. Off-line event selection based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a similar to 100 mCrab source between 25 and 50 keV. A 6-h observation of the Crab pulsar will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma significance; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. Long-duration flights will measure the dependence of the polarisation across the cyclotron absorption line in Hercules X-1. A scaled-down instrument will be flown as a pathfinder mission from the north of Sweden in 2010. The first science flight is planned to take place shortly thereafter. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

  • PoGOLite - A high sensitivity balloon-borne soft gamma-ray polarimeter

    Tuneyoshi Kamae, Viktor Andersson, Makoto Arimoto, Magnus Axelsson, Cecilia Marini Bettolo, Claes-Ingvar Bjornsson, Gilles Bogaert, Per Carlson, William Craig, Tomas Ekeberg, Olle Engdegdrd, Yasushi Fukazawa, Shuichi Gunji, Linnea Hjalmarsdotter, Bianca Iwan, Yoshikazu Kanai, Jun Kataoka, Nobuyuki Kawai, Jaroslav Kazejev, Mozsi Kiss, Wlodzimierz Klamra, Stefan Larsson, Grzegorz Madejski, Tsunefumi Mizuno, Johnny Ng, Mark Pearce, Felix Ryde, Markus Suhonen, Hiroyasu TaJima, Hiromitsu Takahashi, Tadayuki Takahashi, Takuya Tanaka, Timothy Thurston, Masaru Ueno, Gary Varneri, Kazuhide Yamamoto, Yuichiro Yamashita, Tomi Ylinen, Hiroaki Yoshida

    ASTROPARTICLE PHYSICS   30 ( 2 ) 72 - 84  2008.09

     View Summary

    We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200 mCrab point-like sources between 25 and 80 keV in one 6-h flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. Synchrotron radiation, inverse Compton scattering and propagation through high magnetic fields are likely to produce high degrees of polarisation in the energy band of the instrument. We demonstrate, through tests at accelerators, with radioactive sources and through computer simulations, that PoGOLite will be able to detect degrees of polarisation as predicted by models for several classes of high energy sources. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles while securing a large effective area has been the greatest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow Held of view (FWHM = 1.25 msr, 2.0 deg x 2.0 deg) obtained with detector cells and the use of thick background shields warrant a large effective area for polarisation measurements (similar to 228 cm(2) at E = 40 keV) without sacrificing the signal-to-noise ratio. Simulation studies for an atmospheric overburden of 3-4 g/cm(2) indicate that neutrons and gamma-rays entering the PDC assembly through the shields are dominant backgrounds. Off-line event selection based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a similar to 100 mCrab source between 25 and 50 keV. A 6-h observation of the Crab pulsar will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma significance; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. Long-duration flights will measure the dependence of the polarisation across the cyclotron absorption line in Hercules X-1. A scaled-down instrument will be flown as a pathfinder mission from the north of Sweden in 2010. The first science flight is planned to take place shortly thereafter. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

  • APDによるNeXT衛星軟γ線検出器BGOアクティブシールドの光読み出し

    池尻祐輝, 深沢泰司, 深水浩司, 片岡淳, 戸泉貴裕, 和田健介, 中澤知洋, 国分紀秀, 高橋忠幸, 田島宏康, 森国城

    日本天文学会年会講演予稿集   2008   263  2008.08

    J-GLOBAL

  • Evolution of and high-energy emission from GHz-peaked spectrum sources

    L. Stawarz, L. Ostorero, M. C. Begelman, R. Moderski, J. Kataoka, S. Wagner

    ASTROPHYSICAL JOURNAL   680 ( 2 ) 911 - 925  2008.06

    Book review, literature introduction, etc.  

     View Summary

    Here we discuss evolution and broadband emission of compact (&lt; kpc) lobes in young radio sources. We propose a simple dynamical description for these objects, consisting of a relativistic jet propagating into a uniform gaseous medium in the central parts of an elliptical host. In the framework of the proposed model we follow the evolution of ultra-relativistic electrons injected from a terminal hot spot of a jet to expanding lobes, taking into account their adiabatic energy losses, as well as radiative cooling. This allows us to discuss the broadband lobe emission of young radio sources. In particular, we argue that the observed spectral turnover in the radio synchrotron spectra of these objects cannot originate from the synchrotron self-absorption process but is most likely due to free-free absorption effects connected with neutral clouds of interstellar medium engulfed by the expanding lobes and photoionized by active centers. We also find a relatively strong and complex high-energy emission component produced by inverse Compton upscattering of various surrounding photon fields by the lobes' electrons. We argue that such high-energy radiation is strong enough to account for several observed properties of GHz-peaked spectrum (GPS) radio galaxies at UV- and X-ray frequencies. In addition, this emission is expected to extend up to GeV (or possibly even TeV) photon energies and can thus be probed by several modern gamma-ray instruments. In particular, we suggest that GPS radio galaxies should constitute a relatively numerous class of extragalactic sources detected by GLAST.

    DOI

  • 次期X線天文衛星NeXT搭載硬X線撮像検出器(HXI)の開発(II)

    国分紀秀, 渡辺伸, 佐藤理江, 武田伸一郎, 石川真之介, 小高裕和, 青野博之, 高橋忠幸, 深沢泰司, 中澤知洋, 片岡淳, 寺田幸功, 山岡和貴, 玉川徹

    日本天文学会年会講演予稿集   2008   247  2008.02

    J-GLOBAL

  • Measuring the broad-band X-ray spectrum from 400 eV to 40 keV in the southwest part of the supernova remnant RX J1713.7-3946

    Tadayuki Takahashi, Takaaki Tanaka, Yasunobu Uchiyama, Junko S. Hiraga, Kazuhiro Nakazawa, Shin Watanabe, Aya Bamba, John P. Hughes, Hideaki Katagiri, Jun Kataoka, Motohide Kokubun, Katsuji Koyama, Koji Mori, Robert Petre, Hiromitsu Takahashi, Yoko Tsuboi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   60   S131 - S140  2008.02

     View Summary

    We report on results from Suzaku broadband X-ray observations of the southwest part of the galactic supernova remnant (SNR) RX J1713.7-3946 with an energy coverage of 0.4-40keV. The X-ray spectrum, presumably of synchrotron origin, is known to be completely lineless, making this SNR ideally suited for a detailed study of the X-ray spectral shape formed through efficient particle acceleration at high-speed shocks. With a sensitive hard X-ray measurement from the HXD PIN aboard Suzaku, we determined the hard X-ray spectrum in the 12-40 keV range to be described by a power law with photon index of Gamma = 3.2 +/- 0.2, significantly steeper than the soft X-ray index of Gamma = 2.4 +/- 0.05 measured previously with ASCA and other missions. We find that a simple power law fails to describe the full spectral range of 0.4-40 keV, and instead a power-law with an exponential cutoff with a hard index of Gamma = 1.50 +/- 0.09 and a high-energy cutoff of epsilon(c) = 1.2 +/- 0.3 keV formally provides an excellent fit over the full bandpass. If we use the so-called SRCUT model, as an alternative model, it gives a best-fit rolloff energy of epsilon(roll) = 0.95 +/- 0.04 keV. Together with the TeV gamma-ray spectrum, ranging from 0.3 to 100 TeV, recently obtained by HESS observations, our Suzaku observations of RX J1713.7-3946 provide stringent constraints on the highest-energy particles accelerated in a supernova shock.

    DOI

  • ガンマ線バースト硬X線偏光観測衛星「つばめ」の開発現状

    戸泉貴裕, 津布久佳宏, 小林光吉, 下川辺隆史, 谷津陽一, 片岡淳, 河合誠之

    日本天文学会年会講演予稿集   2008  2008

    J-GLOBAL

  • ブレーザー3C 454.3の“ガンマ線フレア”多波長同時観測

    森由希, 片岡淳, 河合誠之, 石村拓人, 工藤佑允, 下川辺隆史, 谷津陽一, 高橋忠幸, 佐藤理江, TAVANINI M., TOSTI G., MADEJSKI G., GIOMMI P.

    日本天文学会年会講演予稿集   2008  2008

    J-GLOBAL

  • MITSuME望遠鏡の無人自動観測・自動解析システム

    下川辺隆史, 河合誠之, 片岡淳, 森由希, 工藤佑允, 中嶋英也, 吉田道利, 柳澤顕史, 長山省吾, 戸田博之, 黒田大介, 清水康広, 渡部潤一, 福島英雄, 森正樹

    日本天文学会年会講演予稿集   2008  2008

    J-GLOBAL

  • 23aSH-1 Initial Status of the Gamma-ray Large Area Telescope (GLAST)

    Fukazawa Y, Kawai N, Kataoka J, Nakamori T, Kanai Y, Shimokawabe T, Takahashi T, Ozaki M, Ohno M, Sato R, Kamae T, Ohsugi T, Tajima H, Tanaka T, Okumura A, Makishima K, CLAST team, Mizuno T, Katagiri H, Takahashi H, Yasuda H, Nishino S, Yoshida H, Hanabata Y

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 )  2008

    CiNii J-GLOBAL

  • Multiwavelength observations of the powerful gamma-ray quasar PKS 1510-089: Clues on the jet composition

    J. Kataoka, G. Madejski, M. Sikora, P. Roming, M. M. Chester, D. Grupe, Y. Tsubuku, R. Sato, N. Kawai, G. Tosti, D. Impiombato, Y. Y. Kovalev, Y. A. Kovalev, P. G. Edwards, S. J. Wagner, R. Moderski, L. Stawarz, T. Takahashi, S. Watanabe

    ASTROPHYSICAL JOURNAL   672 ( 2 ) 787 - 799  2008.01

     View Summary

    We present the results from a multiwavelength campaign conducted in 2006 August of the powerful gamma-ray quasar PKS 1510-089 (z = 0.361). This campaign commenced with a deep Suzaku observation lasting 3 days for a total exposure time of 120 ks and continued with Swift monitoring over 18 days. Besides Swift observations, the campaign included ground-based optical and radio data and yielded a quasi-simultaneous broadband spectrum from 10(9) to 10(19) Hz. The Suzaku observation provided a high signal-to-noise ratio X-ray spectrum, which is well represented by an extremely hard power law with a photon index of Gamma similar or equal to 1.2, augmented by a soft component apparent below 1 keV, which is well described by a blackbody model with a temperature of kT similar or equal to 0.2 keV. Monitoring by Suzaku revealed temporal variability that differs between the low- and high-energy bands, again suggesting the presence of a second, variable component in addition to the primary power-law emission. We model the broadband spectrum, assuming that the high-energy spectral component results from Comptonization of infrared radiation produced by hot dust located in the surrounding molecular torus. The adopted internal shock scenario implies that the power of the jet is dominated by protons, but with a number of electrons and/or positrons that exceeds the number of protons by a factor of similar to 10. We also find that inhomogeneities responsible for the shock formation prior to the collision may produce bulk Compton radiation, which can explain the observed soft X-ray excess and possible excess at similar to 18 keV. We note, however, that the bulk Compton interpretation is not unique, as discussed briefly in the text.

    DOI

  • Oxygen line mapping of SN 1006 with Suzaku

    Aya Bamba, Hiroya Yamaguchi, KatsuJi Koyama, Junko S. Hiraga, Steve Holt, John P. Hughes, Hideaki Katagiri, Jun Kataoka, Satoru Katsuda, Shunji Kitamoto, Motohide Kokubun, Hironori Matsumoto, Emi Miyata, Koji Mori, Hiroshi Nakajima, Masanobu Ozaki, Rob Petre, Akiko Sekiguchi, Tadayuki Takahashi, Takaaki Tanaka, Yukikatsu Terada, Hiroshi Tomida, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Yasunobu Uchiyama, Masaru Ueno, Shin Watanabe

    ADVANCES IN SPACE RESEARCH   41 ( 3 ) 411 - 415  2008

     View Summary

    SN 1006 is one of the supernova remnants (SNRs) with relatively low-temperature electrons, considering the young age of just 1000 years. We carried out SN 1006 mapping observations with the X-ray Imaging Spectrometers (XIS) and the Hard X-ray Detector (HXD) onboard Suzaku, the fifth Japanese X-ray satellite. Thanks to the excellent spectral resolution of XIS in the soft X-ray band, H-like and He-like oxygen emission lines were clearly detected, and we could make a map of the line intensity, and as well as a flux and the photon index of nonthermal component. We found that these parameters have spatial dependences from region to region in the SNR; the north region is bright in nonthermal, while dim in thermal; the east region is bright in both nonthermal and thermal; the inner region shows dim nonthermal and bright thermal emission. The photon index is the smallest in the north region. (C) 2007 Published by Elsevier Ltd on behalf of COSPAR.

    DOI

  • Environmental tests of the flight GLAST LAT tracker towers

    R. Bagagli, L. Baldini, R. Bellazzini, G. Barblellini, F. Belli, T. Borden, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, J. Goodman, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, J. Ku, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, B. Marangelli, F. Marcucci, M. Marchetti, M. M. Massai, M. N. Mazziotta, M. Minori, M. Minuti, N. Mirizzi, M. Mongelli, C. Monte, A. Morselli, D. Nelson, M. Nordby, N. Omodei, M. Pepe, M. Pesce-Rollins, S. Raino, R. Rando, M. Razzano, D. Rich, G. Scolieri, C. Sgro, G. Spandre, P. Spinelli, M. Sugizaki, H. Takahashi, A. Tenze, C. Young

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   584 ( 2-3 ) 358 - 373  2008.01

     View Summary

    The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance. (C) 2007 Elsevier B.V. All rights reserved.

    DOI CiNii

  • Design and initial tests of the Tracker-converter of the Gamma-ray Large Area Space Telescope

    W. B. Atwood, R. Bagagli, L. Baldini, R. Bellazzini, G. Barbiellini, F. Belli, T. Borden, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, R. Giannitrapani, N. Giglietto, F. Giordano, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, M. M. Massai, M. N. Mazziotta, M. Minuti, T. Mizuno, A. Morselli, D. Nelson, M. Nordby, T. Ohsugi, N. Omodei, M. Ozaki, M. Pepe, S. Raino, R. Rando, M. Razzano, D. Rich, H. F. -W. Sadrozinski, G. Scolieri, C. Sgro, G. Spandre, P. Spinelli, M. Sugizaki, H. Tajima, H. Takahashi, T. Takahashi, S. Yoshida, C. Young, M. Ziegler

    ASTROPARTICLE PHYSICS   28 ( 4-5 ) 422 - 434  2007.12

     View Summary

    The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. It is the largest silicon-strip detector system ever built for launch into space, and its aggressive design emphasizes very low power consumption, passive cooling, low noise, high efficiency, minimal dead area, and a structure that is highly transparent to charged particles. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements. It is now installed in the completed LAT, which is being prepared for launch in early 2008. (c) 2007 Elsevier B.V. All rights reserved.

    DOI

  • Construction, test and calibration of the GLAST silicon tracker

    C. Sgro, W. B. Atwood, L. Baldini, G. Barbiellini, R. Bellazzini, F. Belli, E. Bonamente, T. Borden, J. Bregeon, A. Brez, M. Brigida, G. A. Caliandro, C. Cecchi, J. Cohen-Tanugi, A. De Angelis, P. Drell, C. Favuzzi, Y. Fukazawa, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, T. Himel, M. Hirayama, R. P. Johnson, H. Katagiri, J. Kataoka, N. Kawai, W. Kroeger, M. Kuss, L. Latronico, F. Longo, F. Loparco, P. Lubrano, M. M. Massai, M. N. Mazziotta, M. Minuti, T. Mizuno, A. Morselli, D. Nelson, M. Nordby, T. Ohsugi, N. Omodei, M. Ozaki, M. Pepe, S. Raino, R. Rando, M. Razzano, D. Rich, H. F. -W. Sadrozinski, G. Scolieri, G. Spandre, P. Spinelli, M. Sugizaki, H. Tajima, H. Takahashi, T. Takahashi, S. Yoshida, C. Young, M. Ziegler

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   583 ( 1 ) 9 - 13  2007.12

     View Summary

    The Gamma-ray Large Area Space Telescope represents a great advance in space application of silicon detectors. With a surface of 80 m(2) and about 1 M readout channels it is the largest silicon tracker ever built for a space experiment.
    GLAST is an astro-particle mission that will study the mostly unexplored, high energy (20 MeV-300 GeV) spectrum coming from active sources or diffused in the Universe. The detector integration and test phase is complete. The full instrument underwent environmental testing and the spacecraft integration phase has just started: the launch is foreseen in late 2007. In the meanwhile the spare modules are being used for instrument calibration and performance verification employing the CERN accelerator complex. A Calibration Unit has been exposed to photon, electron and hadron beams from a few GeV up to 300 GeV. We report on the status of the instrument and on the calibration campaign. (C) 2007 Elsevier B.V. All rights reserved.

    DOI

  • Measuring energy dependent polarization in soft gamma-rays using compton scattering in PoGOLite

    M. Axelsson, O. Engdegard, F. Ryde, S. Larsson, M. Pearce, L. Hjalmarsdotter, M. Kiss, C. Marini Bettolo, M. Arimoto, C. -I. Bjornsson, P. Carlson, Y. Fukazawa, T. Kamae, Y. Kanai, J. Kataoka, N. Kawal, W. Klamra, G. Madejski, T. Mizuno, J. Ng, H. Tajima, T. Takahashi, T. Tanaka, M. Ueno, G. Varner, K. Yamamoto

    ASTROPARTICLE PHYSICS   28 ( 3 ) 327 - 337  2007.11

     View Summary

    Linear polarization in X-and gamma-rays is an important diagnostic of many astrophysical sources, foremost giving information about their geometry, magnetic fields, and radiation mechanisms. However, very few X-ray polarization measurements have been made, and then only mono-energetic detections, whilst several objects are assumed to have energy dependent polarization signatures. In this paper, we investigate whether detection of energy dependent polarization from cosmic sources is possible using the Compton technique, in particular with the proposed PoGOLite balloon-experiment, in the 25-100 keV range. We use Geant4 simulations of a PoGOLite model and input photon spectra based on Cygnus X-1 and accreting magnetic pulsars (100 mCrab). Effective observing times of 6 and 35 h were simulated, corresponding to a standard and a long duration flight, respectively. Both smooth and sharp energy variations of the polarization are investigated and compared to constant polarization signals using chi-square statistics. We can reject constant polarization, with energy, for the Cygnus X-1 spectrum (in the hard state), if the reflected component is assumed to be completely polarized, whereas the distinction cannot be made for weaker polarization. For the accreting pulsar, constant polarization can be rejected in the case of polarization in a narrow energy band with at least 50% polarization, and similarly for a negative step distribution from 30% to 0% polarization. (c) 2007 Elsevier B.V. All rights reserved.

    DOI

  • Development of wideband X-ray and gamma-ray spectrometer using transmission-type, large-area APD

    S. Tanaka, J. Kataoka, Y. Kanai, Y. Yatsu, M. Arimoto, M. Koizumi, N. Kawai, Y. Ishikawa, S. Kawai, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   582 ( 2 ) 562 - 568  2007.11

     View Summary

    The avalanche photodiode (APD) is a high-performance and compact light sensor recently applied in various fields of experimental physics. Among several types of APDs, the reach-through APD offers an advantage in direct X-ray detection, thanks to its thick depletion layer (&gt;= 100 mu m) in front of the amplification region. This type of APD is also sensitive to weak scintillation light from gamma ray scintillators with a high quantum efficiency of similar to 80% (at lambda similar or equal to 500 nm). In this paper, we propose a novel design of a compact X-rayto-gamma-ray detector widely applicable between 1 keV and several hundreds of keV. The prototype consists of a reach-through APD (transmission type) optically coupled with a cubic CsI(T1) crystal 4 x 4 x 4mm(3) in size. By applying the pulse shape discrimination technique to the APD output, we successfully discriminated the X-ray signals directly detected within the APD (1-40 keV), and gamma ray signals absorbed in a CsI(T1) scintillator (10-800 keV) located immediately behind the APD. Optimum FWHM energy resolutions of 15.1 +/- 0.2%, 6.6 +/- 0.4%, and 7.6 +/- 0.1% were obtained for 5.9 keV X-rays, 32 keV X-rays, and 662 keV gamma rays, respectively, measured at +20 degrees C. This stacked configuration is viable for various future applications in space science and nuclear medicine. (c) 2007 Elsevier B.V. All rights reserved.

    DOI

  • 22pZJ-13 Status of MAXI/GSC

    Kohama M., Suzuki M., Matsuoka M., Kawasaki K., Ueno S., Tomida H., Ishikawa M., Miyakawa Y., Mihara T., Isobe N., Kawai N., Kataoka J., Tanaka S., Yoshida A., Negoro H., Nakajima M., Morii M.

    Meeting abstracts of the Physical Society of Japan   62 ( 2 ) 111 - 111  2007.08

    CiNii

  • 次世代X線天文衛星NeXT搭載,硬X線撮像検出器(HXI)に向けた開発の現状

    渡辺伸, 国分紀秀, 佐藤理江, 武田伸一郎, 石川真之介, 小高裕和, 青野博之, 高橋忠幸, 深沢泰司, 安田創, 田中琢也, 西野翔, 中澤知洋, 奥山翔, 田島宏康, 田中孝明, 片岡淳, 寺田幸功, 玉川徹

    日本天文学会年会講演予稿集   2007   300  2007.08

    J-GLOBAL

  • The Suzaku observation of the nucleus of the radio-loud active galaxy Centaurus A: Constraints on abundances of the accreting material

    A. Markowitz, T. Takahashi, S. Watanabe, K. Nakazawa, Y. Fukazawa, M. Kokubun, K. Makishima, H. Awaki, A. Bamba, N. Isobe, J. Kataoka, G. Madejski, R. Mushotzky, T. Okajima, A. Ptak, J. N. Reeves, Y. Ueda, T. Yamasaki, T. Yaqoob

    ASTROPHYSICAL JOURNAL   665 ( 1 ) 209 - 224  2007.08

     View Summary

    A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3-250 keV. The net exposure times after screening were 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X- ray Detector (HXD) PIN, and 17.1 ks for the HXD GSO. The hard X- rays are fit by two power laws of the same slope, absorbed by columns of 1.5 and 7 x 10(23) cm(-2), respectively. The spectrum is consistent with previous suggestions that the power-law components are X- ray emission from the subparsec VLBI jet and from Bondi accretion at the core, but it is also consistent with a partial-covering interpretation. The soft band is dominated by thermal emission from the diffuse plasma and is fit well by a two-temperature VAPEC model, plus a third power-law component to account for scattered nuclear emission, jet emission, and emission from X- ray binaries and other point sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca, and Ni are detected. The Fe K proportional to line width yields a 200 lt-day lower limit on the distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell absorption edges are detected. Elemental abundances are constrained via absorption edge depths and strengths of the fluorescent and diffuse plasma emission lines. The high metallicity ([Fe/H] = +0.1) of the circumnuclear material suggests that it could not have originated in the relatively metal-poor outer halo unless enrichment by local star formation has occurred. Relative abundances are consistent with enrichment from Type II and Ia supernovae.

    DOI

  • Low-energy cutoffs and hard X-ray spectra in high-z radio-loud quasars: The Suzaku view of RBS 315

    F. Tavecchio, L. Maraschi, G. Ghisellini, J. Kataoka, L. Foschini, R. M. Sambruna, G. Tagliaferri

    ASTROPHYSICAL JOURNAL   665 ( 2 ) 980 - 989  2007.08

     View Summary

    We present the results from the Suzaku observation of the powerful radio-loud quasar RBS 315 (z = 2.69), for which a previous XMM-Newton observation showed an extremely flat X-ray continuum up to 10 keV ( photon index Gamma = 1.26) and indications of strong intrinsic absorption (N-H similar to 10(22) cm(-2), assuming neutral gas). The instrument for hard X-rays, HXD/PIN, allows us a detection of the source up to 50 keV. The broadband continuum (0.5-50 keV) can be well modeled with a power law with slope Gamma = 1.5 (definitively softer than the continuum measured by XMM-Newton) above 1 keV with strong deficit of soft photons. The low-energy cutoff can be well fitted, either with intrinsic absorption ( with column density N-H similar to 10(22) cm(-2) in the quasar rest frame) or with a break in the continuum, with an extremely hard (Gamma = 0.7) power law below 1 keV. We construct the spectral energy distribution of the source, using also optical-UV measurements obtained through a quasi-simultaneous observation with UVOT on board Swift observation. The shape of the SED is similar to that of other flat-spectrumradio quasars (FSRQs) with similar power, making this source an excellent candidate for the detection in gamma-rays by the Gamma-Ray Large Area Space Telescope ( GLAST). We model the SED with the synchrotron inverse Compton model usually applied to FSRQs, showing that the deficit of soft photons can be naturally interpreted as due to an intrinsic curvature of the spectrum near the low-energy end of the IC component, rather than to intrinsic absorption, although the latter possibility cannot be ruled out. We propose that in at least a fraction of the radio-loud QSOs at high redshift, the cutoff in the soft X-ray band can be explained in a similar way. Further studies are required to distinguish between the two alternatives.

    DOI

  • Probing the disk-jet connection of the radio galaxy 3C 120 observed with Suzaku

    Jun Kataoka, James N. Reeves, Kazushi Iwasawa, Alex G. Markowitz, Richard F. Mushotzky, Makoto Arimoto, Tadayuki Takahashi, Yoshihiro Tsubuku, Masayoshi Ushio, Shin Watanabe, Luigi C. Gallo, Greg M. Madejski, Yuichi Terashima, Naoki Isobe, Makoto S. Tashiro, Takayoshi Kohmura

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 2 ) 279 - 297  2007.04

     View Summary

    We report on deep (40 ks x 4) observations of the bright broad line radio galaxy 3C 120 using Suzaku. The observations were spaced one week apart, and sampled a range of continuum fluxes. An excellent broadband spectrum was obtained over two decades of frequency (0.6 to 50 keV) within each 40 ks exposure. We clearly resolved the iron K emission-line complex, finding that it consists of a narrow K alpha core (sigma similar or equal to 110 eV or an EW of 60 eV), a 6.9 keV line, and an underlying broad iron line. Our confirmation of the broad line contrasts with the XMM-Newton observation in 2003, where the broad line was not required. The most natural interpretation of the broadline is iron Kline emission from a face-on accretion disk that is truncated at similar to 10 r(g). Above 10 keV, a relatively weak Compton hump was detected (reflection fraction of R similar or equal to 0.6), superposed on the primary X-ray continuum of Gamma similar or equal to 1.75. Thanks to the good photon statistics and low background of the Suzaku data, we clearly confirm the spectral evolution of 3C 120, whereby the variability amplitude decreases with increasing energy. More strikingly, we discovered that the variability is caused by a steep power-law component of Gamma similar or equal to 2.7, possibly related to non-thermal jet emission. We discuss our findings in the context of similarities and differences between radio-loud/quiet objects.

    DOI

  • 26aSF-8 Multiwavelength and simultaneous observation of TeV blazers with SUZAKU/H.E.S.S/MAGIC

    Ushio Masayoshi, Aharonian F., Costamante L., Wagner S.

    Meeting abstracts of the Physical Society of Japan   62 ( 1 ) 95 - 95  2007.02

    CiNii

  • Hole multiplication in a reverse-type avalanche photodiode

    Mitsuhiro Sato, Takayuki Yanagida, Akira Yoshikawa, Yoichi Yatsu, Jun Kataoka, Fumio Saito

    2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11     1486 - +  2007  [Refereed]

     View Summary

    This paper reports on hole multiplication processes, detected in a reverse-type avalanche photodiode (APD), Hamamatsu Photonics type S8664-55, which has a light sensitive area of 5 x 5 mm and a depletion layer thickness of similar to 40 mu m. When the APD was irradiated from a Am-241 isotope, the 13.9 keV and 17.6 keV X-rays produced spectral peaks, whose pulse height depended strongly on the bias voltage, whereas 57.5 keV photons produced another peak, whose the pulse height was much less bias sensitive. The former are identified with electron multiplication signals, whereas the latter with those due to hole multiplication. By measuring the electron and hole multiplication gains as a function of the bias voltage, the ratio of hole and electron ionization probabilities was determined as 0.0130 +/- 0.0010 at 20 degrees C, and 0.0153 +/- 0.0010 at -20 degrees C.

  • シミュレーションを用いた次世代ガンマ線天文衛星GLASTの感度評価

    吉田広明, 大杉節, 深沢泰司, 片桐秀明, 水野恒史, 高橋弘充, 高橋拓也, 釜江常好, 田島宏康, 田中孝明, 河合誠之, 片岡淳, 植野優, 高橋忠幸, 尾崎正伸

    日本天文学会年会講演予稿集   2007  2007

    J-GLOBAL

  • Beam test of a prototype phoswich detector assembly for the PoGOLite astronomical soft gamma-ray polarimeter

    Y. Kanai, M. Ueno, J. Kataoka, M. Arimoto, N. Kawai, K. Yamamoto, T. Mizuno, Y. Fukazawa, M. Kiss, T. Ylinen, C. Marini Bettolo, P. Carlson, W. Klamra, M. Pearce, P. Chen, B. Craig, T. Kamae, G. Madejski, J. S. T. Ng, R. Rogers, H. Tajima, T. S. Thurston, Y. Saito, T. Takahashi, S. Gunji, C-I Bjornsson, S. Larsson, F. Ryde, G. Bogaert, S. Kishimoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   570 ( 1 ) 61 - 71  2007.01

     View Summary

    We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer-Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4%, 35.8% and 37.2% at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Wide Range Multifrequency Observations of Northern TeV Blazars

    Rugamer

    Astronomische Nachrichten   328   623  2007

  • The X-ray observatory Suzaku

    Kazuhisa Mitsuda, Mark Bautz, Hajime Inoue, Richard L. Kelley, Katsuji Koyama, Hideyo Kunieda, Kazuo Makshima, Yoshiaki Ogawara, Robert Petre, Tadayuki Takahashi, Hiroshi Tsunemi, Nicholas E. White, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Hisamitsu Awaki, Aya Bamba, Kevin Boyce, Gregory V. Brown, Kai-Wing Chan, Jean Cottam, Tadayasu Dotanli, John Doty, Ken Ebisawa, Yuichiro Ezoe, Andrew C. Fabian, Enectali Figueroa, Ryuichi Fujimoto, Yasushi Fukazawa, Tae Furusho, Akihiro Furuzawa, Keith Gendreau, Richard E. Griffiths, Yoshito Haba, Kenji Hamaguchi, Ilana Harrus, Gunther Hasinger, Isamu Hatsukade, Kiyoshi Hayashida, Patrick J. Henry, Junko S. Hiraga, Stephen S. Holt, Ann Hornschemeier, John P. Hughes, Una Hwang, Manabu Ishida, Yoshitaka Ishisaki, Naoki Isobe, Masayuki Itoh, Naoko Iyomoto, Steven M. Kahn, Tuneyoshi Kamae, Hideaki Katagiri, Jun Kataoka, Haruyoshi Katayama, Nobuyuki Kawai, Caroline Kilbourne, Kenzo Kinugasa, Steve Kissel, Shunji Kitamoto, Mitsuhiro Kohama, Takayoshi Kohmura, Motohide Kokubun, Taro Kotani, Jun'ichi Kotoku, Aya Kubota, Greg M. Madejski, Yoshitomo Maeda, Fumiyoshi Makino, Alex Markowitz, Chiho Matsumoto, Hironori Matsumoto, Masaru Matsuoka, Kyoko Matsushita, Dan McCammon, Tatehiko Mihara, Kazutami Misaki, Emi Miyata, Tsunefumi Mizuno, Koji Mori, Hideyuki Mori, Mikio Morii, Harvey Moseley, Koji Mukai, Hiroshi Murakami, Toshio Murakami, Richard Mushotzky, Fumiaki Nagase, Masaaki Namiki, Hitoshi Negoro, Kazubiro Nakazawa, John A. Nousek, Takashi Okajima, Yasushi Ogasaka, Takaya Ohashi, Tai Oshima, Naomi Ota, Masanobu Ozaki, Hideki Ozawa, Arvind N. Parmar, William D. Pence, F. Scott Porter, James N. Reeves, George R. Ricker, Ikuya Sakurai, Wilton T. Sanders, Atsushi Senda, Peter Serlemitsos, Ryo Shibata, Yang Soong, Randall Smith, Motoko Suzuki, Andrew E. Szymkowiak, Hiromitsu Takahashi, Torn Tamagawa, Keisuke Tamura, Takayuki Tamura, Yasuo Tanaka, Makoto Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Hiroshi Tomida, Ken'ichi Torii, Yohko Tsuboi, Masahiro Tsujimoto, Takeshi Go Tsuru, Martin J. L. Turner, Yoshihiro Ueda, Shiro Ueno, Masaru Ueno, Shin'ichiro Uno, Yuji Urata, Shin Watanabe, Norimasa Yamamoto, Kazutaka Yamaoka, Noriko Y. Yamasaki, Koujun Yamashita, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Daisuke Yonetoku, Atsumasa Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 1 SPEC. ISS. ) S1 - S7  2007.01

     View Summary

    High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

    DOI

  • Suzaku observations of HESS J1616-508: Evidence for a dark particle accelerator

    Hironori Matsumoto, Masaru Ueno, Aya Bamba, Yoshiaki Hyodo, Hideyuki Mori, Hideki Uchiyama, Takeshi Go Tsuru, Katsuji Koyama, Jun Kataoka, Hideaki Katagiri, Tadayuki Takahashi, Junko Hiraga, Shigeo Yamauchi, John P. Hughes, Atsushi Senda, Motohide Kokubun, Takayoshi Kohmura, Frederick S. Porter

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 1 SPEC. ISS. ) S199 - S208  2007.01

     View Summary

    We observed the bright unidentified TeV gamma-ray source HESS J1616-508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of 3.1 x 10(-13) erg s(-1) cm(-2) in the 2-10 keV band, which is some 60-times below the gamma-ray flux in the 1-10 TeV band. This object is bright in TeV gamma-rays, but very dim in the X-ray band, and thus is one of the best examples in the Galaxy of a "dark particle accelerator." We also detected soft thermal emission with kT similar to 0.3-0.6 keV near the location of HESS J1616-508. This may be due to a dust-grain scattering halo from the nearby bright supernova remnant RCW 103.

    DOI

  • A Suzaku observation of the low-ionization Fe-Line emission from RCW 86

    Masaru Ueno, Rie Sato, Jun Kataoka, Aya Bamba, Ilana Harrus, Junko Hiraga, John P. Hughes, Caroline A. Kilbourne, Katsuji Koyama, Motohide Kokubun, Hiroshi Nakajima, Masanobu Ozaki, Robert Petre, Tadayuki Takahashi, Takaaki Tanaka, Hiroshi Tomida, Hiroya Yaniaguchi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59 ( 1 SPEC. ISS. ) S171 - S176  2007.01

     View Summary

    The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant RCW 86 in 2006 February to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock, and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line, which we interpret as K beta emission from low-ionization iron. The Fe K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with n(e)t less than or similar to 10(9) cm(-3) s and kT(e) similar to 5 keV. This combination of low n(e)t and high kT(e) suggests collisionless electron heating in an SNR shock. The Fe K alpha line shows evidence for intrinsic broadening, with a width of 47 (34-59) eV (99% error region). The difference in the spatial distributions of the hard continuum above 3 keV and the Fe K line emission supports a synchrotron origin for the hard continuum.

    DOI

  • Beam test of a prototype phoswich detector assembly for the PoGOLite astronomical soft gamma-ray polarimeter

    Y. Kanai, M. Ueno, J. Kataoka, M. Arimoto, N. Kawai, K. Yamamoto, T. Mizuno, Y. Fukazawa, M. Kiss, T. Ylinen, C. Marini Bettolo, P. Carlson, W. Klamra, M. Pearce, P. Chen, B. Craig, T. Kamae, G. Madejski, J. S. T. Ng, R. Rogers, H. Tajima, T. S. Thurston, Y. Saito, T. Takahashi, S. Gunji, C-I Bjornsson, S. Larsson, F. Ryde, G. Bogaert, S. Kishimoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   570 ( 1 ) 61 - 71  2007.01

     View Summary

    We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer-Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4%, 35.8% and 37.2% at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Wide Range Multifrequency Observations of Northern TeV Blazars

    Rugamer

    Astronomische Nachrichten   328   623  2007

  • The X-ray observatory Suzaku

    Kazuhisa Mitsuda, Mark Bautz, Hajime Inoue, Richard L. Kelley, Katsuji Koyama, Hideyo Kunieda, Kazuo Makshima, Yoshiaki Ogawara, Robert Petre, Tadayuki Takahashi, Hiroshi Tsunemi, Nicholas E. White, Naohisa Anabuki, Lorella Angelini, Keith Arnaud, Hisamitsu Awaki, Aya Bamba, Kevin Boyce, Gregory V. Brown, Kai-Wing Chan, Jean Cottam, Tadayasu Dotanli, John Doty, Ken Ebisawa, Yuichiro Ezoe, Andrew C. Fabian, Enectali Figueroa, Ryuichi Fujimoto, Yasushi Fukazawa, Tae Furusho, Akihiro Furuzawa, Keith Gendreau, Richard E. Griffiths, Yoshito Haba, Kenji Hamaguchi, Ilana Harrus, Gunther Hasinger, Isamu Hatsukade, Kiyoshi Hayashida, Patrick J. Henry, Junko S. Hiraga, Stephen S. Holt, Ann Hornschemeier, John P. Hughes, Una Hwang, Manabu Ishida, Yoshitaka Ishisaki, Naoki Isobe, Masayuki Itoh, Naoko Iyomoto, Steven M. Kahn, Tuneyoshi Kamae, Hideaki Katagiri, Jun Kataoka, Haruyoshi Katayama, Nobuyuki Kawai, Caroline Kilbourne, Kenzo Kinugasa, Steve Kissel, Shunji Kitamoto, Mitsuhiro Kohama, Takayoshi Kohmura, Motohide Kokubun, Taro Kotani, Jun'ichi Kotoku, Aya Kubota, Greg M. Madejski, Yoshitomo Maeda, Fumiyoshi Makino, Alex Markowitz, Chiho Matsumoto, Hironori Matsumoto, Masaru Matsuoka, Kyoko Matsushita, Dan McCammon, Tatehiko Mihara, Kazutami Misaki, Emi Miyata, Tsunefumi Mizuno, Koji Mori, Hideyuki Mori, Mikio Morii, Harvey Moseley, Koji Mukai, Hiroshi Murakami, Toshio Murakami, Richard Mushotzky, Fumiaki Nagase, Masaaki Namiki, Hitoshi Negoro, Kazubiro Nakazawa, John A. Nousek, Takashi Okajima, Yasushi Ogasaka, Takaya Ohashi, Tai Oshima, Naomi Ota, Masanobu Ozaki, Hideki Ozawa, Arvind N. Parmar, William D. Pence, F. Scott Porter, James N. Reeves, George R. Ricker, Ikuya Sakurai, Wilton T. Sanders, Atsushi Senda, Peter Serlemitsos, Ryo Shibata, Yang Soong, Randall Smith, Motoko Suzuki, Andrew E. Szymkowiak, Hiromitsu Takahashi, Torn Tamagawa, Keisuke Tamura, Takayuki Tamura, Yasuo Tanaka, Makoto Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Hiroshi Tomida, Ken'ichi Torii, Yohko Tsuboi, Masahiro Tsujimoto, Takeshi Go Tsuru, Martin J. L. Turner, Yoshihiro Ueda, Shiro Ueno, Masaru Ueno, Shin'ichiro Uno, Yuji Urata, Shin Watanabe, Norimasa Yamamoto, Kazutaka Yamaoka, Noriko Y. Yamasaki, Koujun Yamashita, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Daisuke Yonetoku, Atsumasa Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S1 - S7  2007.01

     View Summary

    High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

    DOI

  • Suzaku observations of HESS J1616-508: Evidence for a dark particle accelerator

    Hironori Matsumoto, Masaru Ueno, Aya Bamba, Yoshiaki Hyodo, Hideyuki Mori, Hideki Uchiyama, Takeshi Go Tsuru, Katsuji Koyama, Jun Kataoka, Hideaki Katagiri, Tadayuki Takahashi, Junko Hiraga, Shigeo Yamauchi, John P. Hughes, Atsushi Senda, Motohide Kokubun, Takayoshi Kohmura, Frederick S. Porter

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S199 - S208  2007.01

     View Summary

    We observed the bright unidentified TeV gamma-ray source HESS J1616-508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of 3.1 x 10(-13) erg s(-1) cm(-2) in the 2-10 keV band, which is some 60-times below the gamma-ray flux in the 1-10 TeV band. This object is bright in TeV gamma-rays, but very dim in the X-ray band, and thus is one of the best examples in the Galaxy of a "dark particle accelerator." We also detected soft thermal emission with kT similar to 0.3-0.6 keV near the location of HESS J1616-508. This may be due to a dust-grain scattering halo from the nearby bright supernova remnant RCW 103.

    DOI

  • Iron and nickel line diagnostics for the Galactic Center diffuse emission

    Katsuji Koyama, Yoshiaki Hyodo, Tatsuya Inui, Hiroshi Nakajima, Hironori Matsumoto, Takeshi Go Tsuru, Tadayuki Takahashi, Yoshitomo Maeda, Noriko Y. Yamazaki, Hiroshi Murakami, Shigeo Yamauchi, Yohko Tsuboi, Atsushi Senda, Jun Kataoka, Hiromitsu Takahashi, Stephen S. Holt, Gregory V. Brown

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S245 - S255  2007.01

     View Summary

    We have observed the diffuse X-ray emission from the Galactic Center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provided excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are Fe I K alpha at 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (Fe XXV K alpha) and hydrogenic (Fe XXVI Ly alpha) ions of iron. In addition, K alpha lines from neutral or low ionization nickel (Ni I K alpha) and He-like nickel (Ni XXVII K alpha), Fe I K beta, Fe XXV K beta, Fe XXVI Ly beta, Fe XXV K gamma, and Fe XXVI Ly gamma were detected for the first time. The line center energies and widths of Fe XXV K alpha and Fe XXVI Ly alpha favor a collisional excitation plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of Fe XXV K alpha/Fe XXV K beta is similar to the ionization temperature determined from that of Fe XXV K alpha/Fe XXVI Ly alpha. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic, in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar abundance.

    DOI

  • Hard X-ray Detector (HXD) on board Suzaku

    Tadayuki Takahashi, Keiichi Abe, Manabu Endo, Yasuhiko Endo, Yuuichiro Ezoe, Yasushi Fukazawa, Masahito Hamaya, Shinya Hirakuri, Soojing Hong, Michihiro Horii, Hokuto Inoue, Naoki Isobe, Takeshi Itoh, Naoko Iyomoto, Tuneyoshi Kamae, Daisuke Kasama, Jun Kataoka, Hiroshi Kato, Madoka Kawaharada, Naomi Kawano, Kengo Kawashima, Satoshi Kawasoe, Tetsuichi Kishishita, Takao Kitaguch, Yoshihito Kobayashi, Motohide Kokubun, Jun'ichi Kotoku, Manabu Kouda, Aya Kubota, Yoshikatsu Kuroda, Greg Madejski, Kazuo Makishima, Kazunori Masukama, Yukari Matsumoto, Takefumi Mitani, Ryohei Miyawaki, Tsunefumi Mizuno, Kunishiro Mori, Masanori Mori, Mio Murashima, Toshio Murakami, Kazuhiro Nakazawa, Hisako Niko, Masaharu Nomachi, Yuu Okada, Masanori Ohno, Kousuke Oonuki, Naomi Ota, Hideki Ozawa, Goro Sato, Shingo Shinoda, Masahiko Sugiho, Masaya Suzuki, Koji Taguchi, Hiromitsu Takahashi, Isao Takahashi, Shin'ichiro Takeda, Ken-ichi Tamura, Takayuki Tamura, Takaaki Tanaka, Chiharu Tanihata, Makoto Tashiro, Yukikatsu Terada, Shin'ya Tominaga, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Takayuki Yanagida, Daisuke Yonetoku

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S35 - S51  2007.01

     View Summary

    The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by the combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of a well-type active shield counter. With an effective area of 142 cm(2) at 20 keV and 273 cm(2) at 150 keV, the background level at sea level reached similar to 1 X 10(-5) cts s(-1) cm(-2) keV(-1) at 30 keV for the PIN diodes, and similar to 2 X 10(-5) cts s(-1) cm(-2) keV(-1) at 100 keV, and similar to 7 X 10(-6) cts s(-1) cm(-2) keV(-1) at 200 keV for the phoswich counter. Tight active shielding of the HXD results in a large array of guard counters surrounding the main detector parts. These anti-coincidence counters, made of similar to 4 cm thick BGO crystals, have a large effective area for sub-MeV to MeV gamma-rays. They work as an excellent gamma-ray burst monitor with limited angular resolution (similar to 5 degrees). The on-board signal-processing system and the data transmitted to the ground are also described.

    DOI

  • A Suzaku observation of the low-ionization Fe-Line emission from RCW 86

    Masaru Ueno, Rie Sato, Jun Kataoka, Aya Bamba, Ilana Harrus, Junko Hiraga, John P. Hughes, Caroline A. Kilbourne, Katsuji Koyama, Motohide Kokubun, Hiroshi Nakajima, Masanobu Ozaki, Robert Petre, Tadayuki Takahashi, Takaaki Tanaka, Hiroshi Tomida, Hiroya Yaniaguchi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   59   S171 - S176  2007.01

     View Summary

    The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant RCW 86 in 2006 February to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock, and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line, which we interpret as K beta emission from low-ionization iron. The Fe K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with n(e)t less than or similar to 10(9) cm(-3) s and kT(e) similar to 5 keV. This combination of low n(e)t and high kT(e) suggests collisionless electron heating in an SNR shock. The Fe K alpha line shows evidence for intrinsic broadening, with a width of 47 (34-59) eV (99% error region). The difference in the spatial distributions of the hard continuum above 3 keV and the Fe K line emission supports a synchrotron origin for the hard continuum.

    DOI

  • Pre-flight performance and radiation hardness of the Tokyo Tech pico-satellite Cute-1.7

    J. Kotoku, J. Kataoka, Y. Kuramoto, Y. Tsubuku, Y. Yatsu, R. Sato, T. Ikagawa, T. Saito, N. Kawai, K. Konoue, N. Miyashita, M. Iai, K. Omagari, M. Kashiwa, H. Yabe, K. Imai, Miyamoto, K. Fujiwara, S. Masumoto, T. Usuda, T. Iljic, A. Konda, S. Sugita, T. Yamanaka, D. Matsuura, T. Sagami, S. Kajiwara, Y. Funaki, S. Matsunaga, T. Shima, S. Kishimoto

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   565 ( 2 ) 677 - 685  2006.09

     View Summary

    The Cute-1.7 was launched successfully in February 2006 as a piggyback satellite of the Astro-F mission. The Cute-1.7 dimensions are 10 x 10 x 20 cm(3) box with a total mass of 3.6kg. It is the second pico-satellite to have been developed completely by students of the Tokyo Institute of Technology (Tokyo Tech.) after the successful launch of the CUTE-I in June 2003. The goals of the Cute-1.7 mission are two-fold: (1) to validate high-performance, commercially available products for the first time in space. We particularly use personal digital assistants (PDAs) as a main computer in orbit (2) to demonstrate new potential uses for small satellites in various space studies, as proposed by the "satellite-core" concept. For the Cute-1.7 mission, we will carry avalanche photo diodes (APDs) as a high-count particle monitor in low-Earth orbit. Here we present details of various ground tests and pre-flight performance of the Cute-1.7 immediately before the launch. Results of the Cute-1.7 mission will provide quick feedback for space applications of APDs in Japan's future X-ray astronomy mission NeXT. (c) 2006 Elsevier B.V. All rights reserved.

    DOI CiNii

  • 23pSH-13 Current Status of Gamma-Ray Large Area Space Telescope (GLAST)

    Takahashi H., Ohsugi T., Fukazawa Y., Mizuno T., Katagiri H., Kawabata K., Kawamoto T., Kamae T., Tajima H., Kawai N., Kataoka J., Takahashi T., the GLAST team

    Meeting abstracts of the Physical Society of Japan   61 ( 2 ) 79 - 79  2006.08

    CiNii

  • An active gain-control system for avalanche photo-diodes under moderate temperature variations

    J. Kataoka, R. Sato, T. Ikagawa, J. Kotoku, Y. Kuramoto, Y. Tsubuku, T. Saito, Y. Yatsu, N. Kawai, Y. Ishikawa, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   564 ( 1 ) 300 - 307  2006.08

     View Summary

    Avalanche photodiodes (APDs) are a promising light sensor for various fields of experimental physics. It has been argued, however, that variation of APD gain with temperature could be a serious problem preventing APDs from replacing traditional photomultiplier tubes (PMTs) in some applications. Here we develop an active gain-control system to keep the APD gain stable under moderate temperature variations. As a performance demonstration of the proposed system, we have tested the response of a scintillation photon detector consisting of a 5 x 5 mm 2 reverse-type APD optically coupled with a CsI(Tl) crystal. We show that the APD gain was successfully controlled under a temperature variation of Delta T = 20 degrees C, within a time-cycle of 6000 s. The best FWHM energy resolution of 6.1 +/- 0.2 % was obtained for 662 keV gamma-rays, and the energy threshold was as low as 6.5 keV, by integrating data from +20 degrees C-0 degrees C cycles. The corresponding values for -20 degrees C-0 degrees C cycles were 6.9 +/- 0.2% and 5.2 keV, respectively. These results are comparable, or only slightly worse than that obtained at a fixed temperature. Our results suggest new potential uses for APDs in various space researches and nuclear physics. As examples, we briefly introduce the NeXT and Cute-1.7 satellite missions that will carry the APDs as scientific instruments for the first time. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Study of avalanche photodiodes for soft X-ray detection below 20 keV

    Y. Yatsu, Y. Kuramoto, J. Kataoka, J. Kotoku, T. Saito, T. Ikagawa, R. Sato, N. Kawai, S. Kishimoto, K. Mori, T. Kamae, Y. Ishikawa, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   564 ( 1 ) 134 - 143  2006.08

     View Summary

    The performance of the large area reach-through avalanche photodiode (APD), manufactured by Hamamatsu Photonics, K.K. as a high resolution X-ray detector is presented. The mentioned APD has an area of 3 mm 0, a fast time response for signal carrier collection and its thick depletion layer of 130 pm shows a potential to be used as an effective X-ray absorber below 20 keV. Having a capacitance of similar to 10 pF and a low dark current of 5 nA for a gain of 15, at room temperature, this APD had demonstrated one of the best energy resolutions within this kind of devices: 6.4% (FWHM) for 5.9 keV photons with a minimum detectable energy of 0.3 keV, measured at -20 degrees C. The experiments for the timing property were made in a synchrotron beam facility using an 8 keV X-ray beam; the reached count rate was above 108 counts/s, corresponding to a very short dead time of 4.5 ns/pulse. In order to test the radiation hardness of the APD, the device was irradiated at a Ring Cyclotron Facility with a 53.5 MeV proton beam. The total dose was of 11.3 krad and no fatal damage was found in the APD, although the dark current of the APD had shown an increase of one order of magnitude. Finally, the obtained results allow us to affirm that the reach-through APD has the potential to become an excellent X-ray detector, especially in the space mission application. (c) 2006 Elsevier B.V. All rights reserved.

    DOI CiNii

  • Dynamics and high-energy emission of the flaring HST-1 knot in the M 87 jet

    L. Stawarz, F. Aharonian, J. Kataoka, M. Ostrowski, A. Siemiginowska, M. Sikora

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   370 ( 2 ) 981 - 992  2006.08

     View Summary

    Stimulated by recent observations of a giant radio-to-X-ray synchrotron flare from Hubble Space Telescope (HST)-1, the innermost knot of the M 87 jet, as well as by the detection of a very high energy gamma-ray emission from M 87, we investigated the dynamics and multiwavelength emission of the HST-1 region. We study thermal pressure of the hot interstellar medium in M 87 and argue for the presence of a gaseous condensation in its central parts. We postulate that this additional feature is linked to the observed central stellar cusp of the elliptical host. Interaction of the jet with such a feature is likely to result in the formation of a stationary converging/diverging reconfinement/reflected shock structure in the innermost parts of the M 87 jet. We show that for a realistic set of the outflow parameters, a stationary and a flaring part of the HST-1 knot located similar to 100 pc away from the active centre can be associated with the decelerated portion of the jet matter placed immediately downstream of the point where the reconfinement shock reaches the jet axis. We discuss a possible scenario explaining a broad-band brightening of the HST-1 region related to the variable activity of the central core. In particular, we show that assuming a previous epoch of the high central black hole activity resulting in ejection of excess particles and photons down along the jet, one may first expect a high-energy flare of HST-1 due to inverse-Comptonization of the nuclear radiation, followed after a few years by an increase in the synchrotron continuum of this region. The synchrotron flare itself could be accompanied by a subsequent inverse-Compton brightening due to upscattering of the ambient (mostly starlight) photons. If this is the case, then the recently observed order-of-magnitude increase in the knot luminosity in all spectral bands could be regarded as an unusual echo of the order-of-magnitude outburst that had happened previously (and could be eventually observed some similar to 40 yr ago) in the highly relativistic active core of the M 87 radio galaxy. We show that very high energy gamma-ray fluxes expected in a framework of the proposed scenario are consistent with the observed ones.

    DOI

  • An active gain-control system for avalanche photo-diodes under moderate temperature variations

    J. Kataoka, R. Sato, T. Ikagawa, J. Kotoku, Y. Kuramoto, Y. Tsubuku, T. Saito, Y. Yatsu, N. Kawai, Y. Ishikawa, N. Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   564 ( 1 ) 300 - 307  2006.08

     View Summary

    Avalanche photodiodes (APDs) are a promising light sensor for various fields of experimental physics. It has been argued, however, that variation of APD gain with temperature could be a serious problem preventing APDs from replacing traditional photomultiplier tubes (PMTs) in some applications. Here we develop an active gain-control system to keep the APD gain stable under moderate temperature variations. As a performance demonstration of the proposed system, we have tested the response of a scintillation photon detector consisting of a 5 x 5 mm 2 reverse-type APD optically coupled with a CsI(Tl) crystal. We show that the APD gain was successfully controlled under a temperature variation of Delta T = 20 degrees C, within a time-cycle of 6000 s. The best FWHM energy resolution of 6.1 +/- 0.2 % was obtained for 662 keV gamma-rays, and the energy threshold was as low as 6.5 keV, by integrating data from +20 degrees C-0 degrees C cycles. The corresponding values for -20 degrees C-0 degrees C cycles were 6.9 +/- 0.2% and 5.2 keV, respectively. These results are comparable, or only slightly worse than that obtained at a fixed temperature. Our results suggest new potential uses for APDs in various space researches and nuclear physics. As examples, we briefly introduce the NeXT and Cute-1.7 satellite missions that will carry the APDs as scientific instruments for the first time. (c) 2006 Elsevier B.V. All rights reserved.

    DOI CiNii

  • The spectral energy distribution of PKS 2004-447: a compact steep-spectrum source and possible radio-loud narrow-line Seyfert 1 galaxy

    L. C. Gallo, P. G. Edwards, E. Ferrero, J. Kataoka, D. R. Lewis, S. P. Ellingsen, Z. Misanovic, W. F. Welsh, M. Whiting, Th. Boller, W. Brinkmann, J. Greenhill, A. Oshlack

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   370 ( 1 ) 245 - 254  2006.07

     View Summary

    An investigation of the spectral energy distribution ( SED) of the compact steep-spectrum (CSS) source and possible radio-loud narrow-line Seyfert 1 galaxy (NLS1), PKS 2004-447, is presented. Five out of six well-studied radio-loud NLS1 share this dual classification [optically defined as an NLS1 with radio definition of a CSS or gigahertz-peaked spectrum (GPS) source], suggesting that the connection could have a physical origin. The SED is created from simultaneous observations (within 24 h) at radio (from Australia Telescope Compact Array), optical/near-infrared (NIR) (from Siding Spring) and UV/X-ray (from XMM-Newton) wave-lengths. The X-ray data show evidence of short-term variability (primarily a similar to 30 per cent increase in the final 4 ks of the observation), a possible soft excess and negligible absorption. Together with the rest of the SED, the X-ray emission is excessive in comparison to synchrotron plus synchrotron self-Compton (SSC) models. The SED can be described with a two-component model consisting of extended synchrotron/SSC emission with Comptonization in the X-rays, though SSC models with a very high electron-to-magnetic energy density ratio cannot be excluded either. The peak emission in the SED appears to be in the NIR, which can be attributed to thermal emission (T approximate to 1000 K) from a dusty torus. Analysis of a. non-contemporaneous, low-resolution optical spectrum suggests that the narrow-line region (NLR) is much more reddened than the X-ray emitting region suggesting that the gas-to-dust ratio in PKS 2004-447 may be very different than in our own Galaxy. This could be achieved if the radio jets in PKS 2004-447 deposits material from the nucleus into the NLR. Long-term radio monitoring of PKS 2004-447 shows a rather constant light curve over nearly a six-month period with the exception of one outburst when the 6.65-GHz flux increased by similar to 35 per cent over 19 d. It is not possible to differentiate between intrinsic or extrinsic (i.e. interstellar scintillation) origins for this outburst, but the detection of the rare event demonstrates the importance of intensive monitoring campaigns. In comparison to general samples of GPS sources, which appear to be X-ray weak, NLS1-CSS/GPS sources possess stronger X-ray emission relative to radio ( comparable to normal radio-loud AGN). In addition, NLS1-CSS/GPS sources also exhibit lower intrinsic absorption than GPS sources of similar X-ray luminosity. This is consistent with the additional X-ray component required for PKS 2004-447, but larger samples of NLS1-CSS/GPS are needed before any conclusive remarks can be made.

    DOI

  • The X-ray jet in Centaurus A: Clues to the jet structure and particle acceleration

    J Kataoka, L Stawarz, F Aharonian, F Takahara, M Ostrowski, PG Edwards

    ASTROPHYSICAL JOURNAL   641 ( 1 ) 158 - 168  2006.04

     View Summary

    We report detailed studies of the X-ray emission from the kiloparsec-scale jet in the nearest active galaxy, Centaurus A. By analyzing the highest quality X-ray data obtained with the Chandra ACIS-S, 41 compact sources (mostly bright jet knots) were found within the jet on angular scales less than 400, 13 of which were newly identified. We construct the luminosity function for the detected jet knots and argue that the remaining emission is most likely to be truly diffuse, rather than resulting from the sum of many unresolved fainter knots. We subtracted the contributions of the bright knots from the total X-ray jet flux, and show that the remaining extended emission has a relatively flat-topped intensity profile in the transverse jet direction, with the intensity peaking at the jet boundaries between 5000 and 17000. We note that limb-brightened morphologies have been observed previously at radio frequencies in a few FR I and FR II jet sources, but never so clearly at higher photon energies. Our result therefore supports a stratified jet model, consisting of a relativistic outflow including a boundary layer with a velocity shear. In addition, we found that the X-ray spectrum of the diffuse component is almost uniform across and along the jet, with an X-ray energy spectral index of alpha(X)approximate to 1, similar to those observed in the compact knots. We discuss this spectral behavior within a framework of shock and stochastic particle acceleration processes, connected with the turbulent, supersonic, and nonsteady nature of the relativistic outflow. We note some evidence for a possible spectral hardening at the outer sheath of the jet, and manifesting itself in observed X-ray spectra of alpha(X)&lt; 0.5 in the most extreme cases. Due to the limited photon statistics of the present data, further deep observations of Centaurus A are required to determine the reality of this finding; however, we note that the existence of the hard X-ray features at outer jet boundaries would provide an important challenge to theories for the evolution of ultrarelativistic particles within extragalactic jets.

    DOI

  • The parsec-scale jet of PKS 0637-752

    Philip G. Edwards, B. Glenn Piner, Steven J. Tingay, James E. J. Lovell, Jun Kataoka, Roopesh Ojha, Yasuhiro Murata

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   58 ( 2 ) 233 - 241  2006.04

     View Summary

    Chandra observations of the quasar PKS 0637-752 during its checkout phase resulted in the unexpected detection of a luminous kiloparsec-scale X-ray jet. The apparent superluminal speed of this jet on the parsec-scale, based on two VSOP and four ground-based observations, has proven crucial to understanding the X-ray production in the arcsec-scale jet. We present here for the first time the full details of the ground-based observations used to determine the parsec-scale jet speed, describe the results of a third VSOP observation, and examine the reported jet speed in the light of more recent ground-based VLBI observations. We find some evidence of increased source activity coincident with extrapolated epochs of jet component ejection, although the monitoring of the source is relatively sparse and the ejection epochs are not tightly constrained. We also construct the spectral energy distribution for the nucleus of PKS 0637-752 and show that it can be modelled well in terms of a one-zone synchrotron self-Compton model of an electron-positron jet with a Doppler factor of similar to 10, consistent with the results of the VLBI observations.

    DOI

  • 30aSD-2 大学小型衛星Cute-1.7によるAPDの宇宙動作実証(30aSD X線・γ線,宇宙線・宇宙物理領域)

    古徳 純一, 片岡 淳, 河合 誠之, 倉本 祐介, 谷津 陽一, 津布久 佳宏, および工学部松永研究室

    日本物理学会講演概要集   61 ( 1 ) 103 - 103  2006.03

    CiNii

  • 28pTF-5 Development of Hard X-Ray Polarimeter PoGO (II)

    Ueno M., Kanai Y., Arimoto M., Kataoka J., Kawai N., Mizuno T., Yamamoto K., Fukazawa Y., Ylinen Tomi P., Kiss Mozsi, Kamae T., Tajima H., Apte Zachary, Gunji S., Takahashi T., Saito Y.

    Meeting abstracts of the Physical Society of Japan   61 ( 1 ) 97 - 97  2006.03

    CiNii

  • 明野ガンマ線バースト観測用50cm望遠鏡の開発

    下川辺隆史, 河合誠之, 片岡淳, 小谷太郎, 佐藤理江, 谷津陽一, 有元誠, 渡部潤一, 福島英雄, 柳澤顕史, 清水康広, 吉田道利, 長山省吾, 太田耕司, 吉田篤正, 黒田大介, 戸田博之

    日本天文学会年会講演予稿集   2006   214  2006.02

    J-GLOBAL

  • すざく衛星によるTeV γ線天体HESS J1616‐508の観測

    松本浩典, 片桐秀明, 鶴剛, 小山勝二, 馬場彩, 千田篤史, 平賀純子, 高橋忠幸, 植野優, 片岡淳

    日本天文学会年会講演予稿集   2006   148  2006.02

    J-GLOBAL

  • すざく衛星による超新星残骸RX J1713.7‐3946の観測

    田中孝明, 高橋忠幸, 中澤知洋, 平賀純子, 渡辺伸, 馬場彩, 高橋弘充, 片岡淳

    日本天文学会年会講演予稿集   2006   149  2006.02

    J-GLOBAL

  • 「三つ目」望遠鏡の3色同時撮像カメラの更新

    長山省吾, 柳澤顕史, 沖田喜一, 清水康広, 吉田道利, 河合誠之, 戸田博之, 小谷太郎, 片岡淳, 佐藤理江, 鈴木素子, 谷津陽一, 有元誠, 下河辺隆史, 太田耕司, 渡部潤一, 黒田大介, 吉田篤正

    日本天文学会年会講演予稿集   2006   215  2006.02

    J-GLOBAL

  • Kiloparsec-scale jets in FR I radio galaxies and the gamma-ray background

    L Stawarz, TM Kneiske, J Kataoka

    ASTROPHYSICAL JOURNAL   637 ( 2 ) 693 - 698  2006.02

     View Summary

    We discuss the contribution of kiloparsec- scale jets in FR I radio galaxies to the diffuse gamma- ray background radiation. The analyzed gamma- ray emission comes from inverse- Compton scattering of starlight photon fields by the ultrarelativistic electrons whose synchrotron radiation is detected from such sources at radio, optical, and X- ray energies. We find that these objects, under the minimum- power hypothesis ( corresponding to a magnetic field of 300 mu G in the brightest knots of these jets), can contribute about one percent to the extragalactic gamma- ray background measured by EGRET. We point out that this result already indicates that the magnetic fields in kiloparsec- scale jets of low- power radio galaxies are not likely to be smaller than 10 mu G on average, as otherwise the extragalactic gamma- ray background would be overproduced.

    DOI

  • Cute-1.7搭載APDモジュールの放射線耐性と性能評価

    津布久佳宏, 谷津陽一, 古徳純一, 片岡淳, 河合誠之, 尾曲邦之, 根田康実, 芦田宏樹

    日本天文学会年会講演予稿集   2006  2006

    J-GLOBAL

  • 27pTF-7 MItsuME-Multicolor Imaging Telescope for Survey and Monstrous Explosions

    Yatsu Y, Kuroda D, Toda H, Yoshida M, Ohta K, Watanabe J, Yoshida A, Shimizu Y, Okita K, Shimokawabe T, Kawai N, Kotani T, Kataoka J, Sato R, Arimoto M, Yanagisawa K, Nagayama S

    Meeting Abstracts of the Physical Society of Japan   61 ( 0 )  2006

    CiNii

  • 超小型衛星Cute1.7+APD 搭載のAPD センサー技術

    片岡 淳

    OplusE 特集 ~宇宙における光学~   10月号 ( vol.28 ) 1037  2006

  • Suzaku observations of iron lines and reflection in AGN

    J. N. Reeves, A. C. Fabian, J. Kataoka, H. Kunieda, A. Markowitz, G. Miniutti, T. Okajima, P. Serlemitsos, T. Takahashi, Y. Terashima, T. Yaqoob

    ASTRONOMISCHE NACHRICHTEN   327 ( 10 ) 1079 - 1086  2006

     View Summary

    Initial results on the iron K-shell line and reflection component in several AGN observed as part of the Suzaku Guaranteed Time program are reviewed. This paper discusses a small sample of Compton-thin Seyferts observed to date with Suzaku; namely MCG-5-23-16, MCG-6-30-15, NGC4051, NGC3516, NGC2110, 3C120 and NGC2992. The broad iron K alpha emission line appears to be present in all but one of these Seyfert galaxies, while the narrow core of the line from distant matter is ubiquitous in all the observations. The iron line in MCG-6-30-15 shows the most extreme relativistic blurring of all the objects, the red-wing of the line requires the inner accretion disk to extend inwards to within 2.2R(g) of the black hole, in agreement with the XMM-Newton observations. Strong excess emission in the Hard X-ray Detector (HXD) above 10 keV is observed in many of these Seyfert galaxies, consistent with the presence of a reflection component from reprocessing in Compton-thick matter (e.g. the accretion disk). Only one Seyfert galaxy (NGC 2110) shows neither a broad iron line nor a reflection component. The spectral variability of MCG-6-30-15, MCG-5-23-16 and NGC 4051 is also discussed. In all 3 cases, the spectra appear harder when the source is fainter, while there is little variability of the iron line or reflection component with source flux. This agrees with a simple two component spectral model, whereby the variable emission is the primary power-law, while the iron line and reflection component remain relatively constant. (c) 2006 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim.

    DOI

  • Development of 2cm-square Hamamatsu avalanche photodiodes for high-resolution X-rays and gamma-rays detection

    R Sato, J Kataoka, Y Kanai, Y Ishikawa, N Kawabata, T Ikagawa, T Saito, Y Kuramoto, N Kawai

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   556 ( 2 ) 535 - 542  2006.01

     View Summary

    The avalanche photodiodes (APDs) have attracted considerable attention in various field of experimental physics, but their uses are still limited in only a few experiments, possibly due to their small surface areas. Here, we report the development of the large-area (similar to 20 mm square) APDs, for future applications to high-resolution X-rays and gamma-rays detection. We have made two prototypes of reverse-type APDs based on different concepts, one consists of a 2 x 2 array of 10 x 10 mm(2) pixels (APD1) and the other is a monolithic pixel of 19 x 19mm(2) size (APD2) to achieve a large effective area. By comparing the dark current and gain characteristics at room temperature (+20 degrees C) and lightly cooled environment (-20 degrees C), we quantitatively discussed the origin of predominant noise source at different temperatures. As a performance demonstration of newly developed APDs. we made a scintillation gamma-ray detector consisting of a 20 x 20 x 5mm(3) CsI(Tl) crystal and a 2cm-square APD. The best FWHM energy resolution of 8.5 +/- 0.2% were obtained for 662 keV gamma-rays at room temperature. Similarly, the best FWHM energy resolution of 8.5 0.2% were obtained for 122 keV gamma-rays at lightly cooled environment. We showed that the minimum detectable energy for scintillation light was 15 keV at 20 degrees C and less than 5 keV at -20 degrees C. (c) 2005 Elsevier B.V. All rights reserved.

    DOI CiNii

  • Design and performance of the soft gamma-ray detector for the NeXT mission

    H Tajima, T Kamae, G Madejski, Mitani, I, K Nakazawa, T Tanaka, T Takahashi, S Watanabe, Y Fukazawa, T Ikagawa, J Kataoka, M Kokubun, K Makishima, Y Terada, M Nomachi, M Tashiro

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   52 ( 6 ) 2749 - 2757  2005.12

     View Summary

    The soft gamma-ray detector (SGD) onboard the Japanese future high energy astrophysics mission (NeXT) is a Compton telescope with narrow field of view, which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor gamma-ray detector which consists of silicon and cadmium telluride (CdTe) detectors. It can detect photons in a wide energy band (0.05-1 MeV) at a background level of 5 x 10(-7) counts/s/cm(2) /keV; the silicon layers are required to improve the performance at a lower energy band (&lt; 0.3 MeV). Excellent energy resolution is the key feature of the SGD, allowing it to achieve both high angular resolution and good background rejection capability. An additional capability of the SGD, its ability to measure gamma-ray polarization, opens up a new window to study properties of astronomical objects. We will present the development of key technologies to realize the SGD: high quality CdTe, low noise front-end application-specific integrated circuit, and bump bonding technology. Energy resolutions of 1.7 keV (full-width at half-maximum) for CdTe pixel detectors and 1.1 keV for Si strip detectors have been measured. We also present the validation of Monte Carlo simulation used to evaluate the performance of the SGD.

    DOI CiNii

  • Chandra observation of the interaction between the hot plasma nebula RCW 89 and the pulsar jet of PSR B1509-58

    Y. Yatsu, N. Kawai, J. Kataoka, T. Kotani, K. Tamura, W. Brinkmann

    Astrophysical Journal   631 ( 1 I ) 312 - 319  2005.09

     View Summary

    We present a Chandra observation of the H II region RCW 89. The nebula lies 10′ north from the central pulsar PSR B1509-58, and it has been suggested that the nebula is irradiated by the pulsar jet. We performed a spectral analysis of the seven brightest emitting regions aligned in a "horseshoe" shape and found that the temperature of the knots increases along the horseshoe in the clockwise direction, while, in contrast, the ionization parameter net decreases. This strongly supports a picture of energy transfer via the precessing pulsar jet. We examined the energy budget assuming that RCW 89 is powered by the pulsar jet and confirmed that the pulsar rotational energy loss is sufficient to drive the nebula. The rate of energy injection into RCW 89 by the jet was estimated from the synchrotron radiation flux. We obtained a heating timescale of 1400 yr, which is consistent with the pulsar characteristic age of 1700 yr. To explain the temperature gradient, we discuss the cooling process for plasma clouds in RCW 89. We argue that the plasma clouds can be cooled down by the adiabatic expansion within 70 yr and form the temperature gradient reflecting the sequential heating by the precessing pulsar jet. We also determined the velocities of the individual plasma clouds by spectral fitting. The plasma clouds in RCW 89 are moving away at 240-860 km s-1, which constrains the inclination angle of the pulsar spin axis i &gt
    50° and the expanding velocity of the shell as vshell &gt
    1100 km s-1. © 2005. The American Astronomical Society. All rights reserved.

    DOI

  • Chandra observation of the interaction between the hot plasma nebula RCW 89 and the pulsar jet of PSR B1509-58

    Y Yatsu, N Kawai, J Kataoka, T Kotani, K Tamura, W Brinkmann

    ASTROPHYSICAL JOURNAL   631 ( 1 ) 312 - 319  2005.09

     View Summary

    We present a Chandra observation of the H (II) region RCW 89. The nebula lies 10' north from the central pulsar PSR B1509-58, and it has been suggested that the nebula is irradiated by the pulsar jet. We performed a spectral analysis of the seven brightest emitting regions aligned in a "horseshoe'' shape and found that the temperature of the knots increases along the horseshoe in the clockwise direction, while, in contrast, the ionization parameter net decreases. This strongly supports a picture of energy transfer via the precessing pulsar jet. We examined the energy budget assuming that RCW 89 is powered by the pulsar jet and confirmed that the pulsar rotational energy loss is sufficient to drive the nebula. The rate of energy injection into RCW 89 by the jet was estimated from the synchrotron radiation flux. We obtained a heating timescale of 1400 yr, which is consistent with the pulsar characteristic age of 1700 yr. To explain the temperature gradient, we discuss the cooling process for plasma clouds in RCW 89. We argue that the plasma clouds can be cooled down by the adiabatic expansion within 70 yr and form the temperature gradient reflecting the sequential heating by the precessing pulsar jet. We also determined the velocities of the individual plasma clouds by spectral fitting. The plasma clouds in RCW 89 are moving away at 240-860 km s(-1), which constrains the inclination angle of the pulsar spin axis i &gt; 50 degrees and the expanding velocity of the shell as nu(shell) &gt; 1100 km s(-1).

    DOI

  • 「三つ目」岡山50cm望遠鏡の試験観測 II

    柳澤顕史, 河合誠之, 太田耕司, 清水康広, 吉田道利, 長山省吾, 沖田喜一, 岡田隆史, 黒田大介, 戸田博之, 小谷太郎, 片岡淳, 佐藤理江, 鈴木素子, 谷津陽一, 有元誠, 下河辺隆史, 渡部潤一, 吉田篤正

    日本天文学会年会講演予稿集   2005   261  2005.08

    J-GLOBAL

  • VLSIを用いたAPD多チャンネル読み出しシステムの開発

    斉藤孝男, 植野優, 片岡淳, 河合誠之, 高島健, 田中孝明, 三谷烈史, 高橋忠幸

    日本天文学会年会講演予稿集   2005   323  2005.08

    J-GLOBAL

  • 15pSA-8 Ground Calibration of Gamma-Ray Large Area Space Telescope(GLAST)

    Takahashi H., Ohsugi T., Fukazawa Y., Mizuno T., Kawabata K., Ohishi M., Kawamoto T., Kamae T., Tajima H., Kawai N., Kataoka J., Takahashi T.

    Meeting abstracts of the Physical Society of Japan   60 ( 2 ) 40 - 40  2005.08

    CiNii

  • X-ray emission properties of large-scale jets, hot spots, and lobes in active galactic nuclei

    J Kataoka, L Stawarz

    ASTROPHYSICAL JOURNAL   622 ( 2 ) 797 - 810  2005.04

     View Summary

    We examine a systematic comparison of jet knots, hot spots, and radio lobes recently observed with Chandra and ASCA. This report discusses the origin of their X-ray emissions and investigates the dynamics of the jets. The data were compiled at well-sampled radio (5 GHz) and X-ray (1 keV) frequencies for more than 40 radio galaxies. We examine three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC), and external Compton (EC) on cosmic microwave background (CMB) photons. For the SYN sources-mostly jet knots in nearby low-luminosity radio galaxies-X-ray photons are produced by ultrarelativistic electrons with energies 10 100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the "expected'' X-ray fluxes under an equipartition hypothesis is presented. We confirm that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and the majority of hot spots, whereas a considerable fraction of jet knots are too bright in X-rays to be explained in this way. We examine two possibilities to account for the discrepancy in a framework of the inverse Compton model: ( 1) the magnetic field is much smaller than the equipartition value, and ( 2) the jets are highly relativistic on kiloparsec and megaparsec scales. We conclude that if the inverse Compton model is the case, the X-ray-bright jet knots are most likely far from the minimum-power condition. We also briefly discuss the other possibility, namely, that the observed X-ray emission from all the jet knots is synchrotron in origin.

    DOI

  • Application of CdTe for the NeXT mission

    T Takahashi, K Nakazawa, S Watanabe, G Sato, T Mitani, T Tanaka, K Oonuki, K Tamura, H Tajima, T Kamae, G Madejski, M Nomachi, Y Fukazawa, K Makishima, M Kokubun, Y Terada, J Kataoka, M Tashiro

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   541 ( 1-2 ) 332 - 341  2005.04

     View Summary

    Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and gamma-ray detection. The high-atomic number of the materials (Z(Cd) = 48, Z(Te) = 52) gives a high quantum efficiency in comparison with Si. The large band-gap energy (E-g = 1.5 eV) allows to operate the detector at room temperature. Based on recent achievements in high-resolution CdTe detectors, in the technology of ASICs and in bump-bonding, we have proposed the novel hard X-ray and gamma-ray detectors for the NeXT mission in Japan. The high-energy response of the super mirror onboard NeXT will enable us to perform the first sensitive imaging observations up to 80keV. The focal plane detector, which combines a fully depleted X-ray CCD and a pixellated CdTe detector, will provide spectra and images in the wide energy range from 0.5 to 80keV. In the soft gamma-ray band up to similar to 1 MeV, a narrow field-of-view Compton gamma-ray telescope utilizing several tens of layers of thin Si or CdTe detector will provide precise spectra with much higher sensitivity than present instruments. The continuum sensitivity will reach several x 10(-8) photons(-1) keV(-1) cm(-1) in the hard X-ray region and a few X 10(-7) photons(-1) keV(-1) cm(-2) in the soft gamma-ray region. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • X-ray emission properties of large-scale jets, hot spots, and lobes in active galactic nuclei

    Jun Kataoka, Łukasz Stawarz

    Astrophysical Journal   622 ( 2 I ) 797 - 810  2005.04

     View Summary

    We examine a systematic comparison of jet knots, hot spots, and radio lobes recently observed with Chandra and ASCA. This report discusses the origin of their X-ray emissions and investigates the dynamics of the jets. The data were compiled at well-sampled radio (5 GHz) and X-ray (1 keV) frequencies for more than 40 radio galaxies. We examine three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC), and external Compton (EC) on cosmic microwave background (CMB) photons. For the SYN sources - mostly jet knots in nearby low-luminosity radio galaxies - X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the "expected" X-ray fluxes under an equipartition hypothesis is presented. We confirm that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and the majority of hot spots, whereas a considerable fraction of jet knots are too bright in X-rays to be explained in this way. We examine two possibilities to account for the discrepancy in a framework of the inverse Compton model: (1) the magnetic field is much smaller than the equipartition value, and (2) the jets are highly relativistic on kiloparsec and megaparsec scales. We conclude that if the inverse Compton model is the case, the X-ray-bright jet knots are most likely far from the minimum-power condition. We also briefly discuss the other possibility, namely, that the observed X-ray emission from all the jet knots is synchrotron in origin. © 2005. The American Astronomical Society. All rights reserved.

    DOI

  • Recent progress of avalanche photodiodes in high-resoution X-rays and gamma-rays detection

    J Kataoka, T Saito, Y Kuramoto, T Ikagawa, Y Yatsu, J Kotoku, M Arimoto, N Kawai, Y Ishikawa, N Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   541 ( 1-2 ) 398 - 404  2005.04

     View Summary

    We have studied the performance of large area avalanche photodiodes (APDs) recently developed by Hamamatsu Photonics K.K, in high-resolution X-rays and gamma-rays detections. We show that reach-through APD can be an excellent soft X-ray detector operating at room temperature or moderately cooled environment. We obtain the best energy resolution ever achieved with APDs, 6.4% for 5.9 keV X-rays, and obtain the energy threshold as low as 0.5 keV measured at -20 degrees C. Thanks to its fast timing response, signal carriers in the APD device are collected within a short time interval of 1.9 ns (FWHM). This type of APDs can therefore be used as a low-energy, high-counting particle monitor onboard the forthcoming Pico-satellite Cute1.7. As a scintillation photon detector, reverse-type APDs have a good advantage of reducing the dark noise significantly. The best FWHM energy resolutions of 9.4 +/- 0.3% and 4.9 +/- 0.2% were obtained for 59.5 and 662 keV gamma-rays, respectively, as measured with a CsI(T1) crystal. Combination of APDs with various other scintillators (BGO, GSO, and YAP) also showed better results than that obtained with a photomultiplier tube (PMT). These results suggest that APD could be a promising device for replacing traditional PMT usage in some applications. In particular 2-dim, APD array, which we present in this paper, will be a promising device for a wide-band X-ray and x-ray imaging detector in future space research and nuclear medicine. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Application of CdTe for the NeXT mission

    Tadayuki Takahashi, Kazuhiro Nakazawa, Shin Watanabe, Goro Sato, Takefumi Mitani, Takaaki Tanaka, Kousuke Oonuki, Ken'Ichi Tamura, Hiroyasu Tajima, Tuneyoshi Kamae, Greg Madejski, Masaharu Nomachi, Yasushi Fukazawa, Kazuo Makishima, Motohide Kokubun, Yukikatsu Terada, Jun Kataoka, Makoto Tashiro

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   541 ( 1-2 ) 332 - 341  2005.04

     View Summary

    Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and γ-ray detection. The high-atomic number of the materials (ZCd=48,ZTe=52) gives a high quantum efficiency in comparison with Si. The large band-gap energy (Eg=1.5eV) allows to operate the detector at room temperature. Based on recent achievements in high-resolution CdTe detectors, in the technology of ASICs and in bump-bonding, we have proposed the novel hard X-ray and γ-ray detectors for the NeXT mission in Japan. The high-energy response of the super mirror onboard NeXT will enable us to perform the first sensitive imaging observations up to 80 keV. The focal plane detector, which combines a fully depleted X-ray CCD and a pixellated CdTe detector, will provide spectra and images in the wide energy range from 0.5 to 80 keV. In the soft γ-ray band up to ∼1MeV, a narrow field-of-view Compton γ-ray telescope utilizing several tens of layers of thin Si or CdTe detector will provide precise spectra with much higher sensitivity than present instruments. The continuum sensitivity will reach several ×10-8photons-1keV-1cm-2 in the hard X-ray region and a few ×10-7photons-1keV-1cm-2 in the soft γ-ray region. © 2005 Elsevier B.V. All rights reserved.

    DOI

  • 明野ガンマ線バースト観測用50cm望遠鏡の開発

    谷津陽一, 河合誠之, 片岡淳, 小谷太郎, 鈴木素子, 佐藤理江, 有元誠, 下川辺隆史, 渡辺潤一, 福島英雄, 柳澤顕史, 清水康広, 吉田道利, 長山省吾, 太田耕司, 吉田篤正, 黒田大介, 戸田博之

    日本天文学会年会講演予稿集   2005   224  2005.02

    J-GLOBAL

  • Study of large area Hamamatsu avalanche photodiode in a gamma-ray scintillation detector

    T Ikagawa, J Kataoka, Y Yatsu, T Saita, Y Kuramoto, N Kawai, M Kokubun, T Kamae, Y Ishikawa, N Kawabata

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   538 ( 1-3 ) 640 - 650  2005.02

     View Summary

    We have carried out study of a large area (10 x 10 mm(2)), reverse-type avalanche photodiode (APD) recently developed by Hamamatsu photonics. It has low dark current of 3 nA at room temperature, and the gain stability was almost the same as prototypical APDs reported in our previous paper. We studied the performance as a gamma-ray detector with four scintillators, CsI(Tl), BGO, GSO(Ce), and YAP(Ce) crystals. For example we obtained the best energy resolution of 4.9 +/- 0.2 % (FWHM) for 662 keV gamma-rays, as measured with a 10 x 10 x 10 mm 3 CsI(Tl) crystal. The minimum detectable energy was as low as 10 keV at 20degreesC and 3.1 keV at -20degreesC. Thanks to its large effective area, this APD can effectively read out photons from larger size scintillators. When coupling to a 300 x 48 mm(2) BGO plate of 3 mm thickness, an FWHM energy resolution of 20.9 +/- 0.2% was obtained for 662 keV gamma-rays, with the minimum detectable energy of about 60 keV at -15degreesC. These results suggest that our prototype APD can be a promising device for various applications replacing traditional PMTs such as use in space for Japan's future X-ray astronomy mission NeXT. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • 高エネルギー天体からの硬X線偏光検出器PoGOの開発

    金井 義和, 片岡 淳, 有元 誠

    宇宙科学シンポジウム   5   312 - 315  2005.01

    CiNii

  • ガンマ線バースト偏光X線観測用小型衛星「燕」の開発

    斉藤 孝男, 有元 誠, 片岡 淳

    宇宙科学シンポジウム   5   309 - 311  2005.01

    CiNii

  • 大学小型衛星Cute-1.7フライトモデルの開発現状

    古徳純一, 倉本祐輔, 片岡淳, 谷津陽一, 津布久佳宏, 河合誠之, 斎藤孝男

    日本天文学会年会講演予稿集   2005  2005

    J-GLOBAL

  • アバランシェ・フォトダイオードの宇宙利用と放射線耐性

    五十川知子, 片岡淳, 谷津陽一, 齊藤孝男, 倉本祐輔, 古徳純一, 河合誠之, 石川嘉隆, 川端信行, 岸本俊二, 嶋達志

    日本天文学会年会講演予稿集   2005  2005

    J-GLOBAL

  • ガンマ線バースト偏光X線観測用小型衛星「燕」の開発

    斉藤孝男, 有元誠, 片岡淳, 倉本祐輔, 谷津陽一, 古徳純一, 五十川知子, 河合誠之, 今井勝俊, 宮本径, 矢部秀幸, 飯沼大, 船木勇佑, 臼田武史, 藤原謙, 桝本晋嗣, 尾曲邦之, 浅見正, 宮澤航, 松永三郎

    日本天文学会年会講演予稿集   2005  2005

    J-GLOBAL

  • X-Ray Emission Properties of Large-Scale Jets, HotSpots, and Lobes in Active Galactic Nuclei

    J.Kataoka &amp, L.Stawarz

    The Astrophysical Journal   622   797  2005

    DOI

  • 活動銀河核の大規模ジェット:X線で探る構造とダイナミクス

    片岡 淳

    天文月報   10月号 ( vol.98 ) 680  2005

  • Chandra observation of the interaction between the plasma nebula RCW89 and the pulsar jet of PSR B1509-58

    Y Yatsu, J Kataoka, N Kawai, K Tamura, W Brinkmann

    YOUNG NEUTRON STARS AND SUPERNOVA REMNANTS   35 ( 6 ) 1066 - 1069  2005

     View Summary

    We present a Chandra observation of the H II region RCW89. The nebula lies 10' north from the central pulsar PSR 131509-58, and it has been suggested that the nebula is irradiated by the pulsar jet. We performed a spectral analysis of the seven brightest emitting regions aligned in a horse-shoe like shape, and found that the temperature of the knots increases along the horse-shoe in the clockwise direction, while, in contrast, the ionization parameter n(e)t decreases. This result implies that RCW89 was heated in sequence. We examined the energy budget assuming that RCW89 is powered by the pulsar jet. The rate of energy injection into RCW89 by the jet was estimated from the synchrotron radiation flux. We obtained a heating time-scale of 1400 yr, which is consistent with the pulsar characteristic age of 1700 yr. To explain the temperature gradient, we discuss the cooling process for plasma clouds in RCW89. We argue that the plasma clumps can be cooled down by the adiabatic expansion within 250 yr, and form the temperature gradient reflecting the sequential heating by the precessing pulsar jet. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI

  • BGO readout with photodiodes as a soft gamma-ray detector at -30 deg

    Nakamoto et

    Nuclear Instruments and Method section-A   2005   536 - 136  2005

    DOI

  • Near-infrared, optical, and X-ray observations of the anomalous X-ray pulsar 4U 0142+61

    M Morii, N Kawai, J Kataoka, Y Yatsu, N Kobayashi, H Terada

    YOUNG NEUTRON STARS AND SUPERNOVA REMNANTS   35 ( 6 ) 1177 - 1180  2005

     View Summary

    We present results from the simultaneous observations of an anomalous X-ray pulsar (AXP) 4U 0142 + 61 on Sep. 2003. We used RXTE, Subaru, and UH88 telescopes to cover X-ray, near-infrared (NIR) (JHK'), and optical (BVRI) bands, respectively. We obtained a simultaneous broadband spectrum for the first time among AXPs. We found NIR excess in the spectrum, which may be another component different from the optical one. We also found a R band dip. We discuss the broadband spectrum covering the optical and X-ray bands in the framework of a self absorbed synchrotron emission from the magnetosphere of magnetar. We also discuss about the R band dip feature, which could put a restriction on the emission models of magnetars. (c) 2005 Published by Elsevier Ltd on behalf of COSPAR.

    DOI

  • Low energy response of a prototype detector array for the PoGO astronomical hard X-ray polarimeter

    J. Kataoka, M. Kanal, T. Arimoto, T. Ikagawa, M. Saito, N. Ueno, R. Kawai, P. Blandford, T. Chen, G. Kamae, T. Madejski, J. Mizuno, H. Ng, T. Tajima, L. Thurston, A. Barbier, J. Harding, S. Krizmanic, J. Hunter, R. Mitchell, E. Streitmatter, R. Groth, D. Fernholtz, Y. Marlow, T. Saito, S. Takahashi, H. Gunji, Y. Sakurai, V. Fukazawa, P. Anderson, W. Carlson, M. Klamra, M. Pearce, S. Suhonen, F. Larsson, C. I. Ryde, G. Bjornsson, S. Bogaert, Kishimoto

    Proceedings of SPIE - The International Society for Optical Engineering   5898   1 - 11  2005

     View Summary

    The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from astrophysical objects in the 30-200 keV range. It is under development for the first flight anticipated in 2008. PoGO is designed to minimize the background by an improved phoswich configuration, which enables a detection of 10 % polarization in a 100 mCrab source in a 6-8 hour observation. To achieve such high sensitivity, low energy response of the detector is important because the source count rate is generally dominated by the lowest energy photons. We have developed new PMT assemblies specifically designed for PoGO to read-out weak scintillation light of one photoelectron (1 p.e.) level. A beam test of a prototype detector array was conducted at the KEK Photon Factory, Tsukuba in Japan. The experimental data confirm that PoGO can detect polarization of 80-85 % polarized beam down to 30 keV with a modulation factor 0.25 ± 0.05.

    DOI

  • Chandra observation of the interaction between the plasma nebula RCW89 and the pulsar jet of PSR B1509-58

    Y Yatsu, J Kataoka, N Kawai, K Tamura, W Brinkmann

    YOUNG NEUTRON STARS AND SUPERNOVA REMNANTS   35 ( 6 ) 1066 - 1069  2005

     View Summary

    We present a Chandra observation of the H II region RCW89. The nebula lies 10' north from the central pulsar PSR 131509-58, and it has been suggested that the nebula is irradiated by the pulsar jet. We performed a spectral analysis of the seven brightest emitting regions aligned in a horse-shoe like shape, and found that the temperature of the knots increases along the horse-shoe in the clockwise direction, while, in contrast, the ionization parameter n(e)t decreases. This result implies that RCW89 was heated in sequence. We examined the energy budget assuming that RCW89 is powered by the pulsar jet. The rate of energy injection into RCW89 by the jet was estimated from the synchrotron radiation flux. We obtained a heating time-scale of 1400 yr, which is consistent with the pulsar characteristic age of 1700 yr. To explain the temperature gradient, we discuss the cooling process for plasma clouds in RCW89. We argue that the plasma clumps can be cooled down by the adiabatic expansion within 250 yr, and form the temperature gradient reflecting the sequential heating by the precessing pulsar jet. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI

  • BGO readout with photodiodes as a soft gamma-ray detector at -30 deg

    Nakamoto et

    Nuclear Instruments and Method section-A   2005   536 - 136  2005

    DOI

  • HETE-2 localization and observations of the gamma-ray burst GRB 020813

    Rie Sato, Takanori Sakamoto, Jun Kataoka, Atsumasa Yoshida, Motoko Suzuki, Junichi Kotoku, Yuji Urata, Yoshihisa Yamamoto, Makoto Arimoto, Toru Tamagawa, Yuji Shirasaki, Ken'ichi Torii, Masaru Matsuoka, Yujin Nakagawa, Toru Yamazaki, Kaoru Tanaka, Miki Maetou, Makoto Yamauchi, Kunio Takagishi, Donald Q. Lamb, Jean-Luc Atteia, Roland Vanderspek, Carlo Graziani, Gregory Prigozhin, Joel Villasenor, J. Garrett Jernigan, Geoffrey B. Crew, Kevin Hurley, George R. Ricker, Stanford E. Woosley, Nat Butler, Al Levine, John P. Doty, Timothy Q. Donaghy, Edward E. Fenimore, Mark Galassi, Michel Boer, Jean-Pascal Dezalay, Jean-François Olive, Joao Braga, Ravi Manchanda, Graziella Pizzichini, Nobuyuki Kawai

    Publications of the Astronomical Society of Japan   57 ( 6 ) 1031 - 1039  2005

     View Summary

    A bright, long gamma-ray burst (GRB) was detected and localized by the instruments on board the High Energy Transient Explorer 2 satellite (HETE-2) at 02:44:19.17 UTC (9859.17 s UT) on 2002 August 13. The location was reported to the GRB Coordinates Network (GCN) about 4 min after the burst. In the prompt emission, the burst had a duration of approximately 125 s, and more than four peaks. We analyzed the time-resolved 2-400 keV energy spectra of the prompt emission of GRB 020813 using the Wide Field X-Ray Monitor (WXM) and the French Gamma Telescope (FREGATE) in detail. We found that the early part of the burst (17-52 s after the burst trigger) shows a depletion of low-energy photons below about 50 keV. It is difficult to explain the depletion by either synchrotron self-absorption or Comptonization. One possibility is that the low-energy depletion may be understood as a mixture of "jitter" radiation with the usual synchrotron radiation component. © 2005. Astronomical Society of Japan.

    DOI

  • Design and performance of soft Gamma-ray detector for NeXT mission

    H. Tajima, T. Kamae, G. Madejski, T. Mitani, K. Nakazawa, T. Tanaka, T. Takahashi, S. Watanabe, Y. Fukazawa, T. Ikagawa, J. Kataoka, M. Kokubun, K. Makishima, Y. Terada, M. Nomachi, M. Tashiro

    IEEE Nuclear Science Symposium Conference Record   1   314 - 321  2004.12

     View Summary

    The Soft Gamma-ray Detector (SGD) on board NeXT (Japanese future high energy astrophysics mission) is a Compton telescope with narrow field of view (FOV), which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor gamma-ray detector which consists of silicon and CdTe (Cadmium Telluride) detectors. It can detect photons in a wide energy band (0.05-1 MeV) at a background level of 5 × 10-7counts/s/cm2/keV; the silicon layers are required to improve the performance at a lower energy band (&lt;0.3 MeV). Excellent energy resolution is the key feature of the SGD, allowing to achieve both high angular resolution and good background rejection capability. An additional capability of the SGD, its ability to measure gamma-ray polarization opens up a new window to study properties of astronomical objects. We will present the development of key technologies to realize the SGD; high quality CdTe, low noise front-end ASIC and bump bonding tecnology. Energy resolutions of 1.7 keV (FWHM) for CdTe pixel detectors and 1.1 keV for Si strip detectors have been measured. We also present the validation of MC simulation used to evaluate the performance of the SGD. © 2004 IEEE.

  • 28pSD-4 硬 X 線偏光計 PoGO の開発と気球実験への応用 (II)(X 線, 宇宙線)

    山下 祐一郎, 郡司 修一, 河合 誠之, 片岡 淳, 有元 誠, 釜江 常好, 水野 恒史, 斉藤 芳隆, 高橋 忠幸, 深沢 泰司, Mitchell John W, Streimatter Robert, Marlow Daniel

    日本物理学会講演概要集   59 ( 2 ) 79 - 79  2004.08

    CiNii

  • 27aZE-4 Chandra Observation of the Interaction between the plasma nebula RCW89 and the Pulsar Jet of PSR B1509 58

    Yatsu Yoichi, Kotani Taro, Kataoka Jun, Kawai Nobuyuki, Tamura Keisuke

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 78 - 78  2004.03

    CiNii

  • Evolution of the synchrotron spectrum in Markarian 421 during the 1998 campaign

    C Tanihata, J Kataoka, T Takahashi, GM Madejski

    ASTROPHYSICAL JOURNAL   601 ( 2 ) 759 - 770  2004.02

     View Summary

    The uninterrupted 7 day ASCA observations of the TeV blazar Mrk 421 in 1998 have clearly revealed that X-ray flares occur repeatedly. In this paper, we present the results of the time-resolved spectral analysis of the combined data taken by ASCA, RXTE, BeppoSAX, and the Extreme Ultraviolet Explorer (EUVE). In this object-and in many other TeV blazars-the precise measurement of the shape of the X-ray spectrum, which reflects the high-energy portion of the synchrotron component, is crucial in determining the high-energy cutoff of the accelerated electrons in the jet. Thanks to the simultaneous broadband coverage, we measured the 0.1-25 keV spectrum resolved on timescales as short as several hours, providing a great opportunity to investigate the detailed spectral evolution at the flares. By analyzing the time-subdivided observations, we parameterize the evolution of the synchrotron peak, where the radiation power dominates, by fitting the combined spectra with a quadratic form [where the nuF(nu) flux at the energy E obeys log nuF(nu)( E)=log (nuF(nu), (peak))-const(log E-log E-peak)(2)]. In this case, we show that there is an overall trend that the peak energy E-peak and peak flux nuF(nu,pea)k increase or decrease together. The relation of the two parameters is best described as E-peak proportional to nuF(nu,peak)(0.7) for the 1998 campaign. Similar results were derived for the 1997 observations, while the relation gave a smaller index when both 1997 and 1998 data were included. On the other hand, we show that this relation, and also the detailed spectral variations, differs from flare to flare within the 1998 campaign. We suggest that the observed features are consistent with the idea that flares are due to the appearance of a new spectral component. With the availability of the simultaneous TeV data, we also show that there exists a clear correlation between the synchrotron peak flux and the TeV flux.

    DOI

  • NeXTが目指すサイエンス:活動銀河ジェットの物理

    片岡 淳, 田代 信, 深沢 泰司

    宇宙科学シンポジウム   4   43 - 46  2004.01

    CiNii

  • 宇宙用アバランシェ・フォトダイオードの開発とNeXT衛星への応用

    五十川 知子, 片岡 淳, 谷津 陽一

    宇宙科学シンポジウム   4   81 - 83  2004.01

    CiNii

  • Well-type硬X線偏光計PoGOの開発と気球実験への応用

    谷津 陽一, 片岡 淳, 五十川 知子

    宇宙科学シンポジウム   4   453 - 455  2004.01

    CiNii

  • 学生主導の小型衛星の開発~展工大Cute1.7の現状~

    倉本祐輔, 谷津陽一, 片岡淳, 古徳純一, 河合誠之, 五十川知子, 斎藤孝男

    日本天文学会年会講演予稿集   2004  2004

    J-GLOBAL

  • Earliest detection of the optical afterglow of GRB 030329 and its variability

    R Sato, N Kawai, M Suzuki, Y Yatsu, J Kataoka, R Takagi, K Yanagisawa, H Yamaoka

    GAMMA-RAY BURSTS: 30 YEARS OF DISCOVERY   727 ( No. ) 307 - 311  2004

     View Summary

    We report the earliest detection of an extremely bright optical afterglow of the gamma-ray burst GRB 030329 using a 30 cm telescope at the Tokyo Institute of Technology (Tokyo, Japan). Our observation started 67 minutes after the burst and continued for two succeeding nights. Combining our data with those reported in GCN Circulars. we find that the early afterglow light curve of the first half day is described by a broken power-law (proportional to t(-alpha)) function with indices alpha(1) = 0.88 +/- 0.01 (0.047 days &lt; t &lt; t(b1)), alpha(2) = 1.18 +/- 0.01 (t(b1) &lt; t &lt; t(b2)), and alpha(3) = 1.81 +/- 0.04 (t(b2) &lt; t &lt; 1.2 days), where t(b1) similar to 0.26 days and t(b2) similar to 0.54 days. respectively. The change of the power-law index at the first break at t similar to 0.26 days is consistent with that expected from a "cooling break".

  • 岡山天体物理観測所のガンマ線バーストフォローアップ50cm望遠鏡

    柳澤顕史, 河合誠之, 太田耕司, 渡部潤一, 吉田篤正, 清水康広, 吉田道利, 長山省吾, 稲田素子, 服部尭, 沖田喜一, 岡田隆史, 渡邊悦二, 黒田大介, 戸田博之, 小谷太郎, 片岡淳, 佐藤理江, 鈴木素子, 谷津陽一

    日本天文学会年会講演予稿集   2004   231  2004

    J-GLOBAL

  • 宇宙用アバランシェ・フォトダイオードの開発:衛星搭載と撮像への応用

    五十川知子, 片岡淳, 斎藤孝男, 谷津陽一, 倉本祐輔, 河合誠之, 深沢泰司, 高橋忠幸, 三谷烈史, 石川嘉隆

    日本天文学会年会講演予稿集   2004   260  2004

    J-GLOBAL

  • Performance of the most recent avalanche photodiodes for future X-ray and gamma-ray astronomy

    J Kataoka, T Ikagawa, Y Yatsu, Y Kuramoto, T Saito, N Kawai, Y Serino, J Kotoku, Y Ishikawa, N Kawabata

    HIGH-ENERGY DETECTORS IN ASTRONOMY   5501   249 - 260  2004

     View Summary

    We report on the performance of the most recent avalanche photodiodes produced by Hamamatsu Photonics, as low-energy X-rays and gamma-rays detectors. APDs share good features of both photo diodes and PMTs, as they are very compact, produce an internal gain of 10-100, and have high quantum efficiency close to 100% in the visible right. Until very recently, however, APDs were limited to very small surfaces, and were mainly used as a digital device for light communication. We have developed large area (up to 10x10 mm(2)) APDs which can be used in the physics experiments. The best energy resolution of 6.4% (FWHM) was obtained in direct detection of 5.9 keV X-rays. The FWHM results of 9.4% and 4.9% were obtained for 59.5 keV and 662 keV gamma-rays respectively, as measured with the CsI(Tl) crystal. The minimum detectable energy for the scintillation light was as low as 1 keV at lightly cooled environment (-20degreesC). Note that our results are the best records ever achieved with APDs. Various applications of APDs are presented for future space research and nuclear medicine. In particular 2-dimensional APD arrays will be a promising device for a wide-band X-ray and gamma-ray imaging detector.

    DOI

  • Ground Support Electronics for testing the preflight performance of the MAXI-GSC

    J Kataoka, Y Serino, N Kawai, T Arakuni, A Yoshida, M Uzawa, M Kohama, Sakurai, I, T Mihara, H Negoro, N Isobe, H Katayama, K Kawasaki, N Kuramata, M Matsuoka, H Tomida, S Ueno, T Yokota, E Miyata, M Nomachi, H Tsunemi

    X-RAY AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY XIII   5165   375 - 386  2004

     View Summary

    MAXI is an X-ray all-sky monitor which will be mounted on the Japanese Experimental Module (JEM) of the International Space Station (ISS) in 2008. The Gas Slit Camera (GSC) consists of 12 one-dimensional position sensitive proportional counters and the sensitivity will be as high as 1 mCrab for a one-week accumulation in the 2-30 keV band. In order to calibrate the detectors and electronic systems thoroughly before the launch, a fast and versatile Ground Support Electronic (GSE) system is necessary. We have developed a new GSE based on VME I/O boards for a Linux workstation. These boards carry reconfigurable FPGAs of 100,000 gates, together with 16 Mbytes of SDRAM. As a demonstration application of using this GSE, we have tested the positional response of a GSC engineering counter. We present a schematic view of the GSE highlighting the functional design, together with a future vision of the ground testing of the GSC flight counters and digital associated processor.

    DOI

  • Earliest detection of the optical afterglow of GRB 030329 and its variability

    R Sato, N Kawai, M Suzuki, Y Yatsu, J Kataoka, R Takagi, K Yanagisawa, H Yamaoka

    ASTROPHYSICAL JOURNAL   599 ( 1 ) L9 - L12  2003.12

     View Summary

    We report the earliest detection of an extremely bright optical afterglow of the gamma-ray burst GRB 030329 using a 30 cm telescope at the Tokyo Institute of Technology ( Tokyo, Japan). Our observation started 67 minutes after the burst and continued for two succeeding nights until the afterglow faded below the sensitivity limit of the telescope (approximately 18 mag). Combining our data with those reported in GCN Circulars, we find that the early afterglow light curve of the first half-day is described by a broken power-law (proportional to(-alpha)) function with indices alpha(1) = 0.88 +/- 0.01 (0.047 days &lt; t &lt;t(b,1)), alpha(2) = 1.18 +/- 0.01 (t(b,1) &lt; t &lt;t(b,2)), and alpha(3) = 1.81 +/- 0.04 (t(b,2) &lt; t &lt; 1.2 days), where t(b,1) similar to 0.26 days and t(b,2) similar to 0.54 days, respectively. The change of the power- law index at the first break at days is consistent with that expected from a " cooling break" when the cooling frequency crossed the optical band. If the interpretation is correct, the decay index before the cooling break implies a uniform interstellar medium environment.

    DOI

  • Earliest detection of the optical afterglow of GRB 030329 and its variability

    R Sato, N Kawai, M Suzuki, Y Yatsu, J Kataoka, R Takagi, K Yanagisawa, H Yamaoka

    ASTROPHYSICAL JOURNAL   599 ( 1 ) L9 - L12  2003.12

     View Summary

    We report the earliest detection of an extremely bright optical afterglow of the gamma-ray burst GRB 030329 using a 30 cm telescope at the Tokyo Institute of Technology ( Tokyo, Japan). Our observation started 67 minutes after the burst and continued for two succeeding nights until the afterglow faded below the sensitivity limit of the telescope (approximately 18 mag). Combining our data with those reported in GCN Circulars, we find that the early afterglow light curve of the first half-day is described by a broken power-law (proportional to(-alpha)) function with indices alpha(1) = 0.88 +/- 0.01 (0.047 days &lt; t &lt;t(b,1)), alpha(2) = 1.18 +/- 0.01 (t(b,1) &lt; t &lt;t(b,2)), and alpha(3) = 1.81 +/- 0.04 (t(b,2) &lt; t &lt; 1.2 days), where t(b,1) similar to 0.26 days and t(b,2) similar to 0.54 days, respectively. The change of the power- law index at the first break at days is consistent with that expected from a " cooling break" when the cooling frequency crossed the optical band. If the interpretation is correct, the decay index before the cooling break implies a uniform interstellar medium environment.

    DOI

  • Chandra discovery of an X-ray jet and lobes in 3C 15

    J Kataoka, JP Leahy, PG Edwards, M Kino, F Takahara, Y Serino, N Kawai, AR Martel

    ASTRONOMY & ASTROPHYSICS   410 ( 3 ) 833 - 845  2003.11

     View Summary

    We report the Chandra detection of an X-ray jet in 3C 15. The peak of the X-ray emission in the jet is 4.1" ( a projected distance of 5.1 kpc) from the nucleus, and coincident with a component previously identified in the radio and optical jets. We construct the spectral energy distribution ( SED) for this component, optical knot C, and find that X-ray flux is well below the extrapolation of the radio-to-optical continuum. We examine four models for the X-ray jet emission: (I) weak synchrotron cooling in equipartition, (II) moderate synchrotron cooling in equipartition, ( III) weak synchrotron plus synchrotron self-Compton (SSC) cooling, and (IV) moderate synchrotron plus SSC cooling. Given weak evidence for a concave feature in the X-ray spectrum, we argue that case (II) can most reasonably explain the overall emission from knot C. Case (III) is also possible, but requires a large departure from equipartition and for the jet power to be comparable to that of the brightest quasars. In all models, (I)-(IV), electrons must be accelerated up to gamma(max) greater than or similar to 10(7), suggesting that re-acceleration is necessary in knot C of the 3C 15 jet. Diffuse X-ray emission has also been detected, distributed widely over the full extent (63 kpc x 25 kpc) of the radio lobes. The X-ray spectrum of the diffuse emission is described by a two-component model, consisting of soft thermal plasma emission from the host galaxy halo and a hard nonthermal power-law component. The hard component can be ascribed to the inverse Comptonization of cosmic microwave background (CMB) photons by the synchrotron emitting electrons in the radio lobes. We compare the total energy contained in the lobes with the jet power estimated from knot C, and discuss the energetic link between the jet and the lobes. We argue that the fueling time (t(fuel)) and the source age (t(src)) are comparable for case (II), whereas t(fuel) &lt;&lt; t(src) is likely for case (III). The latter may imply that the jet has a very small filling factor, similar to 10(-3). We consider the pressure balance between the thermal galaxy halo and non-thermal relativistic electrons in the radio lobes. Finally, we show that the X-ray emission from the nucleus is not adequately fitted by a simple absorbed power-law model, but needs an additional power-law with heavy absorption (N-H similar or equal to 10(22-23) cm(-2)) intrinsic to the source. Such a high column density is consistent with the presence of a dense, dusty torus which obscures the quasar nucleus.

    DOI

  • Chandra discovery of an X-ray jet and lobes in 3C 15

    J Kataoka, JP Leahy, PG Edwards, M Kino, F Takahara, Y Serino, N Kawai, AR Martel

    ASTRONOMY & ASTROPHYSICS   410 ( 3 ) 833 - 845  2003.11

     View Summary

    We report the Chandra detection of an X-ray jet in 3C 15. The peak of the X-ray emission in the jet is 4.1" ( a projected distance of 5.1 kpc) from the nucleus, and coincident with a component previously identified in the radio and optical jets. We construct the spectral energy distribution ( SED) for this component, optical knot C, and find that X-ray flux is well below the extrapolation of the radio-to-optical continuum. We examine four models for the X-ray jet emission: (I) weak synchrotron cooling in equipartition, (II) moderate synchrotron cooling in equipartition, ( III) weak synchrotron plus synchrotron self-Compton (SSC) cooling, and (IV) moderate synchrotron plus SSC cooling. Given weak evidence for a concave feature in the X-ray spectrum, we argue that case (II) can most reasonably explain the overall emission from knot C. Case (III) is also possible, but requires a large departure from equipartition and for the jet power to be comparable to that of the brightest quasars. In all models, (I)-(IV), electrons must be accelerated up to gamma(max) greater than or similar to 10(7), suggesting that re-acceleration is necessary in knot C of the 3C 15 jet. Diffuse X-ray emission has also been detected, distributed widely over the full extent (63 kpc x 25 kpc) of the radio lobes. The X-ray spectrum of the diffuse emission is described by a two-component model, consisting of soft thermal plasma emission from the host galaxy halo and a hard nonthermal power-law component. The hard component can be ascribed to the inverse Comptonization of cosmic microwave background (CMB) photons by the synchrotron emitting electrons in the radio lobes. We compare the total energy contained in the lobes with the jet power estimated from knot C, and discuss the energetic link between the jet and the lobes. We argue that the fueling time (t(fuel)) and the source age (t(src)) are comparable for case (II), whereas t(fuel) &lt;&lt; t(src) is likely for case (III). The latter may imply that the jet has a very small filling factor, similar to 10(-3). We consider the pressure balance between the thermal galaxy halo and non-thermal relativistic electrons in the radio lobes. Finally, we show that the X-ray emission from the nucleus is not adequately fitted by a simple absorbed power-law model, but needs an additional power-law with heavy absorption (N-H similar or equal to 10(22-23) cm(-2)) intrinsic to the source. Such a high column density is consistent with the presence of a dense, dusty torus which obscures the quasar nucleus.

    DOI

  • Variability timescale and jet power of 3C 273

    Jun Kataoka, Nobuyuki Kawai

    New Astronomy Reviews   47 ( 6-7 ) 685 - 687  2003.10

    Book review, literature introduction, etc.  

     View Summary

    We present the results of a long-look monitoring of 3C 273 with RXTE between 1996 and 2000. A total of 230 observations amounts to a net exposure of 845 ks, with this spectral and variability analysis of 3C 273 covering the longest observation period available at hard X-ray energies. Our new observations imply that 3C 273 is a unique object whose hard X-ray emission occasionally contains a component which is not related to a beamed emission (Seyfert like), but most hard X-rays are likely to originate in inverse Compton radiation from the relativistic jet (blazar like). We consider the 'power balance' (both radiative and kinetic) between the accretion disk, sub-pc-scale jet, and the 10 kpc-scale jet. © 2003 Elsevier B.V. All rights reserveed.

    DOI

  • Chandra observation of the anomalous X-ray pulsar 1E 1841-045

    M Morii, R Sato, J Kataoka, N Kawai

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   55 ( 3 ) L45 - L48  2003.06

     View Summary

    We present the results from a Chandra ACIS CC mode observation of an anomalous X-ray pulsar (AXP) 1E 1841-045. This was the first observation in which the pulsar spectrum over a wide energy range was spatially discriminated from the surrounding SNR, Kes 73. Like other AXPs, the phase-integrated spectrum was fitted well with a power-law plus blackbody model. The spectral parameters are Gamma = 2.0 +/- 0.3, kT(BB) = 0.44 +/- 0.02 keV, and N-H = 2.54(-0.13)(+0.15) x 10(22)cm(-2). This photon index is the flattest among AXPs, and resembles soft gamma-ray repeaters (SGRs) in a quiescent state. The pulse profile is double-peaked, and we found that the second peak has a significantly hard spectrum. The spectra of all phases are consistent with a power-law plus blackbody model with a constant temperature and photon index. When fitted with a two-blackbody model, we obtained a similarly good fit. These results can be interpreted by saying that there are two emission regions with different energy spectra.

    DOI

  • Implications of variability patterns observed in TeV blazars on the structure of the inner jet

    C Tanihata, T Takahashi, J Kataoka, GM Madejski

    ASTROPHYSICAL JOURNAL   584 ( 1 ) 153 - 163  2003.02

     View Summary

    The recent long-look X-ray observations of TeV blazars have revealed many important new features concerning their time variability. In this paper we suggest a physical interpretation for those features based on the framework of the internal and external shock scenarios. We present a simplified model applicable to TeV blazars and investigate through simulations how each of the model parameters would affect the observed light curve or spectrum. In particular, we show that the internal shock scenario naturally leads to all the observed variability properties, including the structure function, but for it to be applicable, the fractional fluctuation of the initial bulk Lorentz factors must be small, sigma'(Gamma) = sigma(Gamma)/Gamma(avg) &lt;&lt; 0.01. This implies very low dynamical efficiency of the internal shock scenario. We also suggest that several observational quantities such as the characteristic timescale, the relative amplitude of flares as compared to the steady ("offset") component, and the slope of the structure function can be used to probe the inner jet. The results are applied to the TeV blazar Mrk 421, and this, within the context of the model, leads to the determination of several physical parameters: the ejection of a shell with average thickness of similar to10(13) cm occurs on average every 10 minutes, and the shells collide similar to10(17) cm away from the central source.

    DOI

  • Chandra detection of hotspot and knots of 3C 303

    J Kataoka, P Edwards, M Georganopoulos, F Takahara, S Wagner

    ASTRONOMY & ASTROPHYSICS   399 ( 1 ) 91 - 97  2003.02

     View Summary

    We report the detection at X-rays of the radio/optical hotspot and knots of 3C 303 from a short (15 ksec) Chandra exposure in 2001 March. The X-ray morphology is similar to that of the radio/optical emission with peaks in the X-ray emission found at 5.5" (knot B), 9" (knot C) and 17" (hotspot) from the core of 3C 303. Despite the limited signal-to-noise ratio of the short Chandra exposure, the X-ray photon spectrum was measured for the hotspot. We construct the spectral energy distribution (SED) and find that the X-ray flux is well below the extrapolation of the radio-to-optical continuum, which we interpret as resulting from the production of X-rays via inverse Compton scattering of both synchrotron photons (SSC) and cosmic microwave background photons (EC/CMB). The magnetic field strength, region size, and the maximum energy of electrons are self-consistently determined for the hotspot to be B similar or equal to 4.3 muG, R similar or equal to 6.5 x 10(21) cm, and gamma(max) similar or equal to 1.4 x 10(7). This implies a magnetic field strength a factor of similar to30 below the equipartition value; B-eq 150 muG. The origin of this large departure from equipartition is still uncertain, but the discrepancy is reduced if the plasma in the hotspot is moving with mildly relativistic speeds. Our observation of 3C 303, as well as recent Chandra detections of large scale jets and hotspots in a number of radio galaxies, confirm that particles are accelerated very efficiently in radio galaxies.

    DOI

  • 50kg級ガンマ線バースト観測衛星の概念設計

    山本 佳久, 片岡 淳, 河合 誠之

    宇宙科学シンポジウム   3   507 - 514  2003.01

    CiNii

  • Chandra Detection of Hot Spot and Knots of 3C303

    J.Kataoka

      399   91  2003

  • Performance of Large Area Avalanche Photodiode as a Low Signal Photon Detector

    Ikagawa et

    Nuclear Instruments and Method section-A   515   663  2003

  • Performance of Large Area Avalanche Photodiode as a Low Signal Photon Detector

    Ikagawa et

    Nuclear Instruments and Method section-A   515   663  2003

  • Implications of Variability Patterns Observed in TeV Blazars on the Structure of the Inner Jet

    Tanihata et

    The Astrophysical Journal   584   153  2003

    DOI

  • Chandra Observation of the Anomalous X-Ray Pulsar 1E 1841-045

    PASJ

    Morii et al.   55 ( 3 ) L45 - 48  2003

    CiNii

  • Chandra Detection of Hot Spot and Knots of 3C303

    J.Kataoka

      399   91  2003

  • RXTE observations of 3C 273 between 1996 and 2000: variability time-scale and jet power

    J Kataoka, C Tanihata, N Kawai, F Takahara, T Takahashi, PG Edwards, F Makino

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   336 ( 3 ) 932 - 944  2002.11

     View Summary

    We present the results of a long-look monitoring of 3C 273 with RXTE between 1996 and 2000. A total of 230 observations amounts to a net exposure of 845 ks, with this spectral and variability analysis of 3C 273 covering the longest observation period available at hard X-ray energies. Flux variations by a factor of 4 have been detected over 4 yr, whereas flux variations of less than 30 per cent have been observed for individual flares on time-scales of similar to3 d. Two temporal methods, the power spectrum density (PSD) and the structure function (SF), have been used to study the variability characteristics of 3C 273. The hard X-ray photon spectra generally show a power-law shape with a differential photon index of Gamma similar or equal to 1.6 +/- 0.1. In 10 of 261 data segments, exceptions to power-law behaviour have been found: (i) an additional soft excess below 4 keV; and (ii) a broad Fe fluorescent line feature with EW similar to 100-200 eV. Our new observations of these previously reported X-ray features may imply that 3C 273 is a unique object whose hard X-ray emission occasionally contains a component that is not related to a beamed emission (Seyfert-like), but most hard X-rays are likely to originate in inverse Compton radiation from the relativistic jet (blazar-like). Multifrequency spectra from radio to gamma-rays are presented in addition to our RXTE results. The X-ray time variability and spectral evolution are discussed in the framework of the beamed, synchrotron self-Compton picture. We consider the 'power balance' (both radiative and kinetic) between the accretion disc, the sub-parsec-scale jet and the 10-kpc-scale jet.

    DOI

  • Observation of gamma rays greater than 10 TeV from Markarian 421

    K Okumura, A Asahara, GV Bicknell, PG Edwards, R Enomoto, S Gunji, S Hara, T Hara, S Hayashi, C Itoh, S Kabuki, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, S Maeda, A Maeshiro, Y Matsubara, Y Mizumoto, M Mori, M Moriya, H Muraishi, Y Muraki, T Naito, T Nakase, K Nishijima, M Ohishi, Patterson, JR, K Sakurazawa, R Suzuki, DL Swaby, K Takano, T Takano, T Tanimori, F Tokanai, K Tsuchiya, H Tsunoo, K Uruma, A Watanabe, S Yanagita, T Yoshida, T Yoshikoshi

    ASTROPHYSICAL JOURNAL   579 ( 1 ) L9 - L12  2002.11

     View Summary

    We have observed Markarian 421 in 2001 January and March with the CANGAROO-II imaging Cerenkov telescope during an extraordinarily high state at TeV energies. From 14 hr of observations at very large zenith angles, similar to70degrees, a signal of 298 +/- 52 gamma-ray-like events (5.7 sigma) was detected at E &gt; 10 TeV, where a higher sensitivity is achieved than those of usual observations near the zenith, owing to a greatly increased collecting area. Under the assumption of an intrinsic power-law spectrum, we derived a differential energy spectrum dN/dE p (3.3 +/- 0.9(stat) +/- 0.3(syst)) x 10(-13) (E/10 TeV)(-(4.0+/-0.60.9, stat +/-0.3syst)) photons cm(-2) s(-1) TeV-1, which is steeper than those previously measured around 1 TeV and supports the evidence for a cutoff in the spectrum of Mrk 421. However, the 4 sigma excess at energies greater than 20 TeV in our data favors a cutoff energy of similar to8 TeV, at the upper end of the range previously reported from measurements at TeV energies.

    DOI

  • Status of Monitor of All-sky X-ray Image(MAXI) onboard ISS

    Mihara T., Negoro H., Kohama M., Sakurai I., Nakajima M., Makishima K., Matsuoka M., Ueno S., Tomida H., Isobe N., Kawai N., Kataoka J., Yoshida A., Tsunemi H., Miyata E.

    Meeting abstracts of the Physical Society of Japan   57 ( 2 ) 78 - 78  2002.08

    CiNii

  • Performance of the ASTRO-E hard X-ray detector

    M Tashiro, T Kamae, K Makishima, T Takahashi, T Murakami, Y Fukazawa, M Kokubun, K Nakazawa, M Nomachi, A Yoshida, Y Ezoe, N Isobe, N Iyomoto, J Kataoka, J Kotoku, M Kouda, S Kubo, A Kubota, Y Matsumoto, T Mizuno, GM Madejski, Y Okada, N Ota, H Ozawa, G Sato, M Sugiho, M Sugizaki, Takahashi, I, H Takahashi, T Tamura, C Tanihata, Y Terada, Y Uchiyama, S Watanabe, K Yamaoka, D Yonetoku

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE   49 ( 4 ) 1893 - 1897  2002.08

     View Summary

    This paper summarizes the design and performance of the hard X-ray detector constructed for the ASTRO-E satellite. The detector utilizes the GSO/BGO well-type phoswich counters in a compound-eye configuration to achieve an extremely low background level of a few x 10(-5) counts s(-1) cm(-2)keV(-1) [1]. The GSO scintillators installed in the BGO active shield wells are sensitive to 30-600 keV photons, while the 2-mm-thick silicon PIN diodes, placed in front of each GSO crystal, cover the 10-60 keV energy band with a spectral resolution of similar to3.5-keV full-width at half-maximum. The design goals, of both low background and high energy resolution, in the hard X-ray bands were verified through the preflight calibration experiments.

    DOI

  • Multi-wavelength Observations of Blazars and the Implications on Particle Acceleration in Jets

    KATAOKA Jun, TAKAHASHI Tadayuki, TANIHATA Chiharu, KUBO Hidetoshi

    The Astronomical herald   95 ( 8 ) 418 - 425  2002.07

    CiNii

  • The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946

    R Enomoto, T Tanimori, T Naito, T Yoshida, S Yanagita, M Mori, PG Edwards, A Asahara, GV Bicknell, S Gunji, S Hara, T Hara, S Hayashi, C Itoh, S Kabuki, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, S Maeda, A Maeshiro, Y Matsubara, Y Mizumoto, M Moriya, H Muraishi, Y Muraki, T Nakase, K Nishijima, M Ohishi, K Okumura, Patterson, JR, K Sakurazawa, R Suzuki, DL Swaby, K Takano, T Takano, F Tokanai, K Tsuchiya, H Tsunoo, K Uruma, A Watanabe, T Yoshikoshi

    NATURE   416 ( 6883 ) 823 - 826  2002.04

     View Summary

    Protons with energies up to similar to10(15) eV are the main component(1) of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking(2). Electrons are known to be accelerated to cosmic-ray energies in supernova remnants(3,4), and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi(0)), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in gamma-rays with a particular spectral-energy distribution(5,6). Here we report the observation of cascade showers of optical photons resulting from g-rays at energies of similar to10(12) eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.

    DOI PubMed CiNii

  • ブレーザーの他波長同時か観測と粒子加速への示唆

    片岡 淳 他

    天文月報   8月号 ( vol.95 ) 373  2002

  • RXTE observations of 3C 273 between 1996 and 2000:Variability Timescale and Jet Power

    Kataoka et

    Mon. Not. Roy. Astron. Soc.   336   932  2002

    DOI

  • RXTE observations of 3C 273 between 1996 and 2000:Variability Timescale and Jet Power

    J.Kataoka

    Mon. Not. Roy. Astron. Soc.   336   932  2002

    DOI

  • Design study of CANGAROO-III, stereoscopic imaging atmospheric Cherenkov telescopes for sub-TeV gamma-ray detection

    R Enomoto, S Hara, A Asahara, GV Bicknell, PG Edwards, S Gunji, T Hara, J Jimbo, F Kajino, H Katagiri, J Kataoka, A Kawachi, T Kifune, H Kubo, J Kushida, Y Matsubara, Y Mizumoto, M Mori, M Moriya, H Muraishi, Y Muraki, T Naito, T Nakase, K Nishijima, K Okumura, Patterson, JR, K Sakurazawa, DL Swaby, K Takano, T Tanimori, T Tamura, K Tsuchiya, K Uruma, S Yanagita, T Yoshida, T Yoshikoshi, A Yuki

    ASTROPARTICLE PHYSICS   16 ( 3 ) 235 - 244  2002.01

     View Summary

    CANGAROO-III is an imaging atmospheric Cherenkov telescope array of four 10-m telescopes for very high energy (sub-TeV) gamma-ray astronomy. A design study of the CANGAROO-III telescope system was carried out using the Monte Carlo technique in order to optimize the pixel size and the telescope spacing. Studies were also made of observations at low elevation angles. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • Variability timescales of TeV blazars observed in the ASCA continuous long-look X-ray monitoring

    C Tanihata, CM Urry, T Takahashi, J Kataoka, SJ Wagner, GM Madejski, M Tashiro, M Kouda

    ASTROPHYSICAL JOURNAL   563 ( 2 ) 569 - 581  2001.12

     View Summary

    Three uninterrupted, long (lasting respectively 7, 10, and 10 days) ASCA observations of the well-studied TeV-bright blazars Mrk 421, Mrk 501, and PKS 2155-304 all show continuous strong X-ray flaring. Despite the relatively faint intensity states in two of the three sources, there was no identifiable quiescent period in any of the observations. Structure function analysis shows that all blazars have a characteristic timescale of similar to1 day, comparable to the recurrence time and to the timescale of the stronger flares. On the other hand, examination of these flares in more detail reveals that each of the strong flares is not a smooth increase and decrease but exhibits substructures of shorter flares having timescales of similar to 10 ks. We verify via simulations that in order to explain the observed structure function, these shorter flares ("shots") are unlikely to be fully random, but in some way are correlated with each other. The energy dependent cross-correlation analysis shows that interband lags are not universal in TeV blazars. This is important since in the past only positive detections of lags were reported. In this work, we determine that the sign of a lag may differ from flare to flare; significant lags of both signs were detected from several flares, while no significant lag was detected from others. However, we also argue that the nature of the underlying component can affect these values. The facts that all flares are nearly symmetric and that fast variability shorter than the characteristic timescale is strongly suppressed, support the scenario where the light crossing time dominates the variability timescales of the day-scale flares.

    DOI

  • Characteristic X-ray variability of TeV blazars: Probing the link between the jet and the central engine

    J Kataoka, T Takahashi, SJ Wagner, N Iyomoto, PG Edwards, K Hayashida, S Inoue, GM Madejski, F Takahara, C Tanihata, N Kawai

    ASTROPHYSICAL JOURNAL   560 ( 2 ) 659 - 674  2001.10

     View Summary

    We have studied the rapid X-ray variability of three extragalactic TeV gamma -ray sources : Mrk 421, Mrk 501, and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or Rossi X-Ray Timing Explorer observations between 1993 and 1998, we have investigated the variability in the time domain from 10(3) to 10(8) s. For all three sources, both the power spectrum density (PSD) and the structure function (SF) show a rollover with a timescale of the order of 1 day or longer, which may be interpreted as the typical timescale of successive flare events. Although the exact shape of turnover is not well constrained and the low-frequency (long timescale) behavior is still unclear, the high-frequency (short timescale) behavior is clearly resolved. We found that, on timescales shorter than 1 day, there is only small power in the variability, as indicated by a steep power spectrum density of f(-2 similar to -3). This is very different from other types of mass-accreting black hole systems, for which the short-timescale variability is well characterized by a fractal, flickering-noise PSD (f(-1 similar to -2)). The steep PSD index and the characteristic timescale of flares imply that the X-ray-emitting site in the jet is of limited spatial extent : D greater than or equal to 10(17) cm distant from the base of the jet, which corresponds to greater than or equal to 10(2) Schwarzschild radii for 10(7-10) M-circle dot black hole systems.

    DOI

  • Data Processor (DP) for Monitor of All-sky X-ray Image (MAXI)

    Kohama M., Mihara T., Negoro H., Yamaoka K., Kawai N., Kataoka J., Yoshida A., Matsuoka M., Tanaka T., Yamaguchi M., Tanaka I.

    Meeting abstracts of the Physical Society of Japan   56 ( 2 ) 47 - 47  2001.09

    CiNii

  • Evidence for a characteristic time-scale in the X-ray light curves of TeV blazars

    Jun Kataoka, Tadayuki Takahashi, Philip G. Edwards, Stefan J. Wagner, Susumu Inoue, Fumio Takahara

    AIP Conference Proceedings   558   660 - 663  2001  [Refereed]  [International journal]  [International coauthorship]

    Article, review, commentary, editorial, etc. (international conference proceedings)  

     View Summary

    We have studied the rapid X-ray variability of four TeV blazars, Mrk 421, Mrk 501, PKS 2155-304 and 1ES 2344+514. Analyzing the X-ray light curves obtained from ASCA and/or RXTE observations, we have investigated the variability in the time domain from 103 to 107 sec. The structure functions show a roll-over around 1 day, which can be interpreted as the typical time-scale of day-by-day flare events. On time-scales shorter than 1 day, variability is significantly suppressed, indicating a steep power spectrum density (PSD) of f-2~-3. This is very different from other types of mass-accreting black-hole systems for which the short timescale variability is well characterized by a fractal, flickering noise (f-1~-2). Importantly, the steep PSD index and the characteristic time-scale of day-by-day flares imply that the X-ray emitting site in the jet is of limited spatial extent; D~=1017-18 cm distant from the base of the jet, which corresponds to ~=102-4Rg for 107-9Msolar black-hole systems.

    DOI

  • Rapid synchrotron flares from BL Lacertae detected by ASCA and RXTE

    C Tanihata, T Takahashi, J Kataoka, GM Madejski, S Inoue, H Kubo, F Makino, Mattox, JR, N Kawai

    ASTROPHYSICAL JOURNAL   543 ( 1 ) 124 - 130  2000.11

     View Summary

    We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray, optical, and gamma -ray emission, with its 2-10 keV flux peaking at similar to3.3 x 10(-11) ergs cm(-2) s(-1). This is more than 3 times higher than the value measured by ASCA in 1995. Ne detected two rapid flares that occurred only in the soft X-ray band, while the hard X-ray flux also increased, but decayed with a much longer timescale. Together with the requirement of a very steep and varying power law dominating the soft X-ray band in addition to the hard power law, we suggest that both the high-energy end of the synchrotron spectrum and the hard inverse Compton spectrum were visible in this source during the outburst. We discuss the possible origins of the observed variability timescales, and interpret the short timescales of the soft X-ray variability as reflecting the size of the emission region.

    DOI

  • Rapid synchrotron flares from BL Lacertae detected by ASCA and RXTE

    C Tanihata, T Takahashi, J Kataoka, GM Madejski, S Inoue, H Kubo, F Makino, Mattox, JR, N Kawai

    ASTROPHYSICAL JOURNAL   543 ( 1 ) 124 - 130  2000.11

     View Summary

    We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray, optical, and gamma -ray emission, with its 2-10 keV flux peaking at similar to3.3 x 10(-11) ergs cm(-2) s(-1). This is more than 3 times higher than the value measured by ASCA in 1995. Ne detected two rapid flares that occurred only in the soft X-ray band, while the hard X-ray flux also increased, but decayed with a much longer timescale. Together with the requirement of a very steep and varying power law dominating the soft X-ray band in addition to the hard power law, we suggest that both the high-energy end of the synchrotron spectrum and the hard inverse Compton spectrum were visible in this source during the outburst. We discuss the possible origins of the observed variability timescales, and interpret the short timescales of the soft X-ray variability as reflecting the size of the emission region.

  • Complex spectral variability from intensive multiwavelength monitoring of Markarian 421 in 1998

    T Takahashi, J Kataoka, G Madejski, J Mattox, CM Urry, S Wagner, F Aharonian, M Catanese, L Chiappetti, P Coppi, B Degrange, G Fossati, H Kubo, H Krawczynski, F Makino, H Marshall, L Maraschi, F Piron, R Remillard, F Takahara, M Tashiro, H Terasranta, T Weekes

    ASTROPHYSICAL JOURNAL   542 ( 2 ) L105 - L109  2000.10

     View Summary

    We conducted a multifrequency campaign for the TeV blazar Markarian 421 in 1998 April. The campaign started from a pronounced high-amplitude flare recorded by BeppoSAX and Whipple; the ASCA observation started 3 days later. In the X-ray data, we detected multiple flares, occurring on timescales of about 1 day. ASCA data clearly reveal spectral variability. The comparison of the data from ASCA, the Extreme Ultraviolet Explorer, and the Rossi X-Ray Timing Explorer indicates that the variability amplitudes in the low-energy synchrotron component are larger at higher photon energies. In TeV gamma -rays, large intraday variations-which were correlated with the X-ray flux-were observed when results from three Cerenkov telescopes were combined. The rms variability of TeV gamma -rays was similar to that observed in hard X-rays, above 10 keV. The X-ray light curve reveals flares that are almost symmetric for most cases, implying that the dominant timescale is the light crossing time through the emitting region. The structure function analysis based on the continuous X-ray light curve of 7 days indicates that the characteristic timescale is similar to0.5 days. The analysis of ASCA light curves in various energy bands appears to show both soft (positive) and hard (negative) lags. These may not be real, as systematic effects could also produce these lags, which are all much smaller than an orbit. If the lags of both signs are red, these imply that the particle acceleration and X-ray cooling timescales are similar.

    DOI

  • Complex spectral variability from intensive multiwavelength monitoring of Markarian 421 in 1998

    T Takahashi, J Kataoka, G Madejski, J Mattox, CM Urry, S Wagner, F Aharonian, M Catanese, L Chiappetti, P Coppi, B Degrange, G Fossati, H Kubo, H Krawczynski, F Makino, H Marshall, L Maraschi, F Piron, R Remillard, F Takahara, M Tashiro, H Terasranta, T Weekes

    ASTROPHYSICAL JOURNAL   542 ( 2 ) L105 - L109  2000.10

     View Summary

    We conducted a multifrequency campaign for the TeV blazar Markarian 421 in 1998 April. The campaign started from a pronounced high-amplitude flare recorded by BeppoSAX and Whipple; the ASCA observation started 3 days later. In the X-ray data, we detected multiple flares, occurring on timescales of about 1 day. ASCA data clearly reveal spectral variability. The comparison of the data from ASCA, the Extreme Ultraviolet Explorer, and the Rossi X-Ray Timing Explorer indicates that the variability amplitudes in the low-energy synchrotron component are larger at higher photon energies. In TeV gamma -rays, large intraday variations-which were correlated with the X-ray flux-were observed when results from three Cerenkov telescopes were combined. The rms variability of TeV gamma -rays was similar to that observed in hard X-rays, above 10 keV. The X-ray light curve reveals flares that are almost symmetric for most cases, implying that the dominant timescale is the light crossing time through the emitting region. The structure function analysis based on the continuous X-ray light curve of 7 days indicates that the characteristic timescale is similar to0.5 days. The analysis of ASCA light curves in various energy bands appears to show both soft (positive) and hard (negative) lags. These may not be real, as systematic effects could also produce these lags, which are all much smaller than an orbit. If the lags of both signs are red, these imply that the particle acceleration and X-ray cooling timescales are similar.

  • Variability pattern and the spectral evolution of the BL lacertae object PKS 2155-304

    J Kataoka, T Takahashi, F Makino, S Inoue, GM Madejski, M Tashiro, CM Urry, H Kubo

    ASTROPHYSICAL JOURNAL   528 ( 1 ) 243 - 253  2000.01

     View Summary

    The TeV blazar PKS 2155 - 304 was monitored with the X-ray satellite ASCA in 1994 May as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a lame flare, in which the 2-10 keV flux changed by a factor of 2 on a timescale of 3 x 10(4) s. During the hare, the increase in the hard X-ray flux clearly preceded that observed in the soft X-rays, with the spectral evolution tracking a "clockwise loop" in the flux versus photon index plane. Ascribing the energy-dependent variability to differential synchrotron cooling of relativistic electrons, we estimate the magnetic field B in the emission region. We tested two different methods of comparing the time series in various X-ray bands: (1) fitting the light curves to a Gaussian function and searching for the time shift of the peak of the flare, and (2) calculating the discrete correlation function. Both methods yielded a consistent solution of B similar to 0.1 G; We also found that the flare amplitude becomes larger as the photon energy increases, while the duration of the flare stays roughly constant throughout the ASCA energy band (0.7-7.5 keV). In the framework of the time-dependent synchrotron self-Compton model in a homogeneous region, we consider a flare where the maximum Lorentz factor (gamma(max)) of the injected electrons increases uniformly throughout the emission volume. The temporal evolution of spectra as well as the light curves were reproduced with the physical parameters self-consistently determined from seven observables. We obtained B similar to 0.1-0.2 G and a region size R similar to 10(-2) pc for relativistic beaming with a Doppler factor of delta similar to 20-30. We discuss the significance of light-travel time effects.

    DOI

  • Variability pattern and the spectral evolution of the BL lacertae object PKS 2155-304

    J Kataoka, T Takahashi, F Makino, S Inoue, GM Madejski, M Tashiro, CM Urry, H Kubo

    ASTROPHYSICAL JOURNAL   528 ( 1 ) 243 - 253  2000.01

     View Summary

    The TeV blazar PKS 2155 - 304 was monitored with the X-ray satellite ASCA in 1994 May as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a lame flare, in which the 2-10 keV flux changed by a factor of 2 on a timescale of 3 x 10(4) s. During the hare, the increase in the hard X-ray flux clearly preceded that observed in the soft X-rays, with the spectral evolution tracking a "clockwise loop" in the flux versus photon index plane. Ascribing the energy-dependent variability to differential synchrotron cooling of relativistic electrons, we estimate the magnetic field B in the emission region. We tested two different methods of comparing the time series in various X-ray bands: (1) fitting the light curves to a Gaussian function and searching for the time shift of the peak of the flare, and (2) calculating the discrete correlation function. Both methods yielded a consistent solution of B similar to 0.1 G; We also found that the flare amplitude becomes larger as the photon energy increases, while the duration of the flare stays roughly constant throughout the ASCA energy band (0.7-7.5 keV). In the framework of the time-dependent synchrotron self-Compton model in a homogeneous region, we consider a flare where the maximum Lorentz factor (gamma(max)) of the injected electrons increases uniformly throughout the emission volume. The temporal evolution of spectra as well as the light curves were reproduced with the physical parameters self-consistently determined from seven observables. We obtained B similar to 0.1-0.2 G and a region size R similar to 10(-2) pc for relativistic beaming with a Doppler factor of delta similar to 20-30. We discuss the significance of light-travel time effects.

  • Variability Pattern and the Spectral Evolution of the BL Lacertae Object PKS 2155-304

    J.Kataoka

    The Astrophysical Journal   528 ( 1 ) 243 - 253  2000

    DOI

  • A study of high energy emission from the TeV blazar Mrk 501 during multiwavelength observations in 1996

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartmann, GM Madejski, P Sreekumar, SJ Wagner

    BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES   25 ( 3-4 ) 737 - 740  2000

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA. EGRET, Whipple, and optical telescopes. We report here for the first time the detection of GeV gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). Higher flux was also observed in April/May 1996, with 4.0 sigma for E &gt; 100 MeV, and 5.2 sigma for E &gt; 500 MeV. We find that the multiband spectrum in March 1996 is consistent with that calculated from a one-zone SSC model, except for the extremely 'flat' TeV spectrum. We show that this flat spectrum cannot be explained by either 2nd order Comptonization or the contribution of the 'seed' IR photons from the host galaxy. (C) 2000 COSPAR. Published by Elsevier Science Ltd.

  • Thick and large area PIN diodes for hard X-ray astronomy

    N Ota, T Murakami, M Sugizaki, H Kaneda, T Tamura, H Ozawa, T Kamae, K Makishima, T Takahashi, M Tashiro, Y Fukazawa, J Kataoka, K Yamaoka, S Kubo, C Tanihata, Y Uchiyama, K Matsuzaki, N Iyomoto, M Kokubun, T Nakazawa, A Kubota, T Mizuno, Y Matsumoto, N Isobe, Y Terada, M Sugiho, T Onishi, H Kubo, H Ikeda, M Nomachi, T Ohsugi, M Muramatsu, H Akahori

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   436 ( 1-2 ) 291 - 296  1999.10

     View Summary

    Thick and large area PIN diodes for the hard X-ray astronomy in the 10-60 keV range are developed. To cover this energy range in a room temperature and in a low background environment, Si PIN junction diodes of 2 mm in thickness with 2.5 cm(2) in effective area were developed, and will be used in the bottom of the Phoswich Hard X-ray Detector (HXD), on-board the ASTRO-E satellite. Problems related to a high purity Si and a thick depletion layer during our development and performance of the PIN diodes are presented in detail. (C) 1999 Elsevier Science B.V. All rights reserved.

    DOI CiNii

  • Multiwavelength observations of the TeV blazar Mrk 501 in March 1996. The first report of the detection by EGRET

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartman, GM Madejski, P Sreekumar, SJ Wagner

    ASTROPARTICLE PHYSICS   11 ( 1-2 ) 149 - 151  1999.06

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA, EGRET, Whipple, and optical telescopes. We report here for the first time the detection of a GeV gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). A higher flux was also observed in April/May 1996, with 4.0 sigma significance for E &gt; 100 MeV, and 5.2 sigma significance for E &gt; 500 MeV. We find that the multiband spectrum in March 1996 is consistent with that calculated from a one-zone SSC model, except for the extremely 'flat' TeV spectrum. We show that the discrepancy cannot be explained by either second order Comptonization or the contribution of the 'seed' IR photons from the host galaxy. (C) 1999 Elsevier Science B.V. All rights reserved.

  • High-energy emission from the TeV blazar Markarian 501 during multiwavelength observations in 1996

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartman, GM Madejski, P Sreekumar, SJ Wagner

    ASTROPHYSICAL JOURNAL   514 ( 1 ) 138 - 147  1999.03

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in 1996 March with ASCA, EGRET, Whipple, and optical telescopes. The X-ray flux observed with ASCA was 5 times higher than the quiescent level and gradually decreased by a factor of 2 during the observation in 1996 March. In the X-ray band, a spectral break was observed around 2 keV. We report here for the first time the detection of high-energy gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). Higher flux was also observed in 1996 April-May, with 4.0 sigma significance for E &gt; 100 MeV and 5.2 sigma significance for E &gt; 500 MeV. The gamma-ray spectrum was measured to be flatter than most of the gamma-ray blazars. We find that the multiband spectrum in 1996 is consistent with that calculated from a one-zone synchrotron self-Compton (SSC) model in which X-rays are produced via synchrotron emission and gamma-rays are produced via inverse Compton scattering of synchrotron photons in a homogeneous region. The flux of TeV gamma-rays is consistent with the predictions of the model if the decrease of the Compton scattering cross section in the Klein-Nishina regime is considered. In the context of this model, we investigate the values of the magnetic field strength and the beaming factor allowed by the observational results. We compare the 1996 March multiwavelength spectrum with that in the flare state in 1997 April. Between these two epochs, the TeV flux increase is well correlated with that observed in keV range. The keV and TeV amplitudes during the 1997 April hare are accurately reproduced by a one-zone SSC model, assuming that the population of synchrotron photons in 1996 are scattered by newly injected relativistic electrons having maximum energies of gamma(max) similar to 6 x 10(6). However, the TeV spectrum observed during the 1996 March campaign is flatter than predicted by our models. We find that this cannot be explained by either higher order Comptonization or the contribution of the "seed" IR photons from the host galaxy for the first-order external radiation. Comptonization, but we cannot exclude possible effects of the IR photons that may arise in the parsec-size tori postulated to exist in active galactic nuclei.

    DOI

  • High-energy emission from the TeV blazar Markarian 501 during multiwavelength observations in 1996

    J Kataoka, Mattox, JR, J Quinn, H Kubo, F Makino, T Takahashi, S Inoue, RC Hartman, GM Madejski, P Sreekumar, SJ Wagner

    ASTROPHYSICAL JOURNAL   514 ( 1 ) 138 - 147  1999.03

     View Summary

    We present the results of a multiwavelength campaign for Mrk 501 performed in 1996 March with ASCA, EGRET, Whipple, and optical telescopes. The X-ray flux observed with ASCA was 5 times higher than the quiescent level and gradually decreased by a factor of 2 during the observation in 1996 March. In the X-ray band, a spectral break was observed around 2 keV. We report here for the first time the detection of high-energy gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E &gt; 100 MeV). Higher flux was also observed in 1996 April-May, with 4.0 sigma significance for E &gt; 100 MeV and 5.2 sigma significance for E &gt; 500 MeV. The gamma-ray spectrum was measured to be flatter than most of the gamma-ray blazars. We find that the multiband spectrum in 1996 is consistent with that calculated from a one-zone synchrotron self-Compton (SSC) model in which X-rays are produced via synchrotron emission and gamma-rays are produced via inverse Compton scattering of synchrotron photons in a homogeneous region. The flux of TeV gamma-rays is consistent with the predictions of the model if the decrease of the Compton scattering cross section in the Klein-Nishina regime is considered. In the context of this model, we investigate the values of the magnetic field strength and the beaming factor allowed by the observational results. We compare the 1996 March multiwavelength spectrum with that in the flare state in 1997 April. Between these two epochs, the TeV flux increase is well correlated with that observed in keV range. The keV and TeV amplitudes during the 1997 April hare are accurately reproduced by a one-zone SSC model, assuming that the population of synchrotron photons in 1996 are scattered by newly injected relativistic electrons having maximum energies of gamma(max) similar to 6 x 10(6). However, the TeV spectrum observed during the 1996 March campaign is flatter than predicted by our models. We find that this cannot be explained by either higher order Comptonization or the contribution of the "seed" IR photons from the host galaxy for the first-order external radiation. Comptonization, but we cannot exclude possible effects of the IR photons that may arise in the parsec-size tori postulated to exist in active galactic nuclei.

  • Preflight performance of the ASTRO-E hard-x-ray detector

    OTA Naomi, Tanihata, C, Kataoka, J, Murakami, T, Ota, N, Ozawa, H, Takahashi, T, Tamura, T, Uchiyama, Y, Watanabe, S, Yamaoka, K, Yonetoku, D, Ezoe, Y, Fukazawa, Y, Isobe, N, Iyomoto, N

    Proc. SPIE   3765   645 - 663  1999

     View Summary

    The Hard X-ray Detector (HXD) is one of the three experiments of the Astro-E mission, the fifth Japanese X-ray satellite devoted to studies of high energy phenomena in the universe in the X-ray to soft gamma-ray region. Prepared for launch at the beginning of 2000 via the newly developed M-V launch vehicle of the Institute of Space and Astronautical Science, the Astro-E is to be thrown into a near-circular orbit of 550 km altitude, with an inclination of 31 degrees. The flight model has been finished assembled this year, and we carried out various tests to verify the performance. We acquired the background spectrum at sea level, and confirmed that our system is operating effectively in reducing the background level. The HXD will observe photons in the energy range of 10-600 keV, and the calculations based on the preflight calibration suggest that the HXD will have the highest sensitivity ever achieved in this energy range. We also verified that our electronic system will maintain its performance against charged particle events expected in orbit.

  • Activation of the ASTRO-E hard X-ray detector in low earth orbit

    M. Kokubun, Y. Fukazawa, E. Idesawa, J. Kataoka, T. Kamae, K. Matsuzaki, T. Mizuno, Y. Saito, T. Takahashi, K. Takizawa, M. Tashiro, T. Tamura, A. Yoshida

    IEEE Transactions on Nuclear Science   46 ( 3 ) 371 - 376  1999

     View Summary

    ASTRO-E Hard X-ray Detector (HXD) is characterized by well-type phoswich counters[1] in a compound-eye configuration which reduce the detector background to lower level than any other past hard X-ray mission. When operating in Low Earth Orbit, the expected background of the HXD is an order of 10 -5 counts/s/kcV/cm 2, mainly caused from the radioactivity induced within the detector materials by geomagnetically trapped protons. Results are presented from measurements of induced radioactivity in two phoswich scintillators, GSO (Gd 2SiO 5:Ce 0.5% mol) and BGO (Bi 4Ge 3O 12), irradiated by mono-energetic protons at an accelerator facility. Radiation transport computer codes are used to build the detector response functions for emissions from decays of spallation products. Based on the comparison between experimental and simulation results, the activation background level of HXD in the orbit is estimated. © 1999 IEEE.

    DOI CiNii

  • 2a-J-5 ASTRO-E搭載硬X線検出器アナログ処理回路の開発(phoswich-I)

    谷畑 千春, 片岡 淳, 寺田 幸功, 水野 恒史, 江澤 元, 田代 信, 深沢 泰司, 高橋 忠幸, 牧島 一夫, 釜江 常好, 森國 城

    日本物理学会講演概要集   53 ( 1 ) 80 - 80  1998.03

    CiNii

  • Evaluation Test of Photomultiplier Tube for Hard Xray Detector on bord ASTRO-E

    TERADA Y., MIZUNO T., FUKAZAWA Y., MAKISHIMA K., KAMAE T., TAKAHASHI T., KATAOKA J., TANIHATA T., HXD TEAM

    Meeting abstracts of the Physical Society of Japan   53 ( 1 ) 56 - 56  1998.03

    CiNii

  • Verification of the Astro-E Hard X-ray Detector based on newly developed Ground Support Equipment

    J Kataoka, M Nomachi, T Takahashi, G Kawaguchi, Y Terada, T Murakami, C Tanihata, Y Uchiyama, K Yamaoka, Y Fukazawa, T Kamae, K Makishima, M Tashiro, H Kubo

    EUV, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY IX   3445   143 - 154  1998

     View Summary

    We report the first results of the ground test of the Hard X-ray Detector (HXD) on board the Astro-E mission, by means of the newly developed Ground Support Equipment (GSE). Astro-E will be launched in 2000 by a Japanese M-V rocket. In order to verify the detector system during the limited time before launch, fast and versatile GSE is necessary. For this, we have developed a flexible test system based on nine VME I/O boards for a SUN workstation. These boards carry reconfigurable Field Programmable Gate Arrays (FPGAs) with 50,000 gates, together with 1 Mbyte SRAM devices tightly coupled to each FPGA device. As an application of using this GSE, we have tested the performance of a phoswich unit of the Flight Model of the HXD. In this paper, we present a schematic view of the GSE highlighting the functional design, and the results of our ground test of the HXD-sensor under the high count rate environment (similar to 10 kHz/unit) expected in orbit.

  • Verification of the Astro-E Hard X-ray Detector based on newly developed Ground Support Equipment

    J Kataoka, M Nomachi, T Takahashi, G Kawaguchi, Y Terada, T Murakami, C Tanihata, Y Uchiyama, K Yamaoka, Y Fukazawa, T Kamae, K Makishima, M Tashiro, H Kubo

    EUV, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY IX   3445   143 - 154  1998

     View Summary

    We report the first results of the ground test of the Hard X-ray Detector (HXD) on board the Astro-E mission, by means of the newly developed Ground Support Equipment (GSE). Astro-E will be launched in 2000 by a Japanese M-V rocket. In order to verify the detector system during the limited time before launch, fast and versatile GSE is necessary. For this, we have developed a flexible test system based on nine VME I/O boards for a SUN workstation. These boards carry reconfigurable Field Programmable Gate Arrays (FPGAs) with 50,000 gates, together with 1 Mbyte SRAM devices tightly coupled to each FPGA device. As an application of using this GSE, we have tested the performance of a phoswich unit of the Flight Model of the HXD. In this paper, we present a schematic view of the GSE highlighting the functional design, and the results of our ground test of the HXD-sensor under the high count rate environment (similar to 10 kHz/unit) expected in orbit.

  • 30p-YM-8 Activation of GSO, BGO scintillators for Hard X-ray Detectors

    Kokubun M., Idesawa E., Kataoka J., Kamae T., Saito Y., Takahashi T., Takizawa K., Tashiro M., Fukazawa Y., Makishima K., Matsuzaki K., Mizuno T., Yoshida A., HXD team

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 74 - 74  1997.03

    CiNii

  • 30p-YM-7 Activation of HXD onboard the Astro-E satellite

    Takizawa K., Idesawa E., Kataoka J., Kamae T., Kokubun M., Saito Y., Takahashi T., Tashiro M., Fukazawa Y., Makishima K., Matsuzaki K., Mizuno T., Yoshida A., HXD team

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 74 - 74  1997.03

    CiNii

  • 30p-YM-9 Evaluation of GSO scintillators for Hard Xray Detector of Astro-E satellite

    Osone S, Kataoka J, Yamaoka K, Takahashi T, HXD team, Kubota A, Matsuzaki K, Kamae T, Fukazawa Y, Saito Y, Ezawa H, Kokubun M, Mizuno T

    Meeting Abstracts of the Physical Society of Japan   52 ( 0 )  1997

    CiNii

  • Development of the hard X-ray detector for the ASTRO-E mission

    T Takahashi, H Ezawa, Y Fukazawa, M Hirayama, E Idesawa, H Ikeda, Y Ishisaki, N Iyomoto, T Kamae, J Kataoka, H Kaneda, H Kubo, K Makishima, K Matsushita, K Matsuzaki, T Mizuno, T Murakami, K Nagata, S Nakamae, M Nomachi, H Obayashi, T Ohtsuka, H Ozawa, Y Saito, M Sugizaki, T Tamura, M Tashiro, N Tsuchida, K Tsukada, A Yoshida

    ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES   120 ( 4 ) C645 - C648  1996.12

     View Summary

    The Hard X-ray Detector (HXD) is one of three instruments on the fifth Japanese X-ray astronomy satellite, ASTRO-E, scheduled for launch in 2000. The HXD consists of a 4x4 = 16 modular assembly of identical counters, each consisting of a combination of YAP(or GSO)/BGO well-type phoswich counters and silicon PIN diodes. The field of view of the detector for high energy photons is restricted to 4 degrees x 4 degrees by active collimators made of BGO and the fov for low energy photons is restricted to 0.5 degrees x 0.5 degrees by the fine passive collimators made of phosphor bronze. The detector is characterized by a low background reaching severalx10(-6) c/s/cm(2)/keV. Combined with the other two instruments for soft X-ray observations (0.5-12 keV), the ASTRO-E mission will cover the entire range of soft and hard X-rays with the highest sensitivity ever achieved. Furthermore, thick EGO counters which surround the 4x4 matrix of well-type phoswich counters act as a gamma-ray burst detector in the energy band of 100-2000 keV.

  • Development of the hard X-ray detector for the ASTRO-E mission

    T Takahashi, H Ezawa, Y Fukazawa, M Hirayama, E Idesawa, H Ikeda, Y Ishisaki, N Iyomoto, T Kamae, J Kataoka, H Kaneda, H Kubo, K Makishima, K Matsushita, K Matsuzaki, T Mizuno, T Murakami, K Nagata, S Nakamae, M Nomachi, H Obayashi, T Ohtsuka, H Ozawa, Y Saito, M Sugizaki, T Tamura, M Tashiro, N Tsuchida, K Tsukada, A Yoshida

    ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES   120 ( 4 ) C645 - C648  1996.12

     View Summary

    The Hard X-ray Detector (HXD) is one of three instruments on the fifth Japanese X-ray astronomy satellite, ASTRO-E, scheduled for launch in 2000. The HXD consists of a 4x4 = 16 modular assembly of identical counters, each consisting of a combination of YAP(or GSO)/BGO well-type phoswich counters and silicon PIN diodes. The field of view of the detector for high energy photons is restricted to 4 degrees x 4 degrees by active collimators made of BGO and the fov for low energy photons is restricted to 0.5 degrees x 0.5 degrees by the fine passive collimators made of phosphor bronze. The detector is characterized by a low background reaching severalx10(-6) c/s/cm(2)/keV. Combined with the other two instruments for soft X-ray observations (0.5-12 keV), the ASTRO-E mission will cover the entire range of soft and hard X-rays with the highest sensitivity ever achieved. Furthermore, thick EGO counters which surround the 4x4 matrix of well-type phoswich counters act as a gamma-ray burst detector in the energy band of 100-2000 keV.

  • ASCA observation of an X-ray/TeV flare from the BL Lacertae object Markarian 421

    T Takahashi, M Tashiro, G Madejski, H Kubo, T Kamae, J Kataoka, T Kii, F Makino, K Makishima, N Yamasaki

    ASTROPHYSICAL JOURNAL   470 ( 2 ) L89 - L92  1996.10

     View Summary

    We observed the BL Lac object Mrk 421 with the X-ray satellite ASCA in 1994 as part of a multifrequency observation. The 24 hr observation was conducted 1 day after the onset of a TeV flare detected by the Whipple Observatory and detected an X-ray flare, with no apparent variability in the optical, UV, and EGRET GeV flux. The ASCA 2-10 keV flux peaked at 3.7 x 10(-10) ergs cm(-2) s(-1) and then decreased to 1.8 x 10(-10) ergs cm(-2) s(-1) with a doubling timescale of similar to 12 hr. The shape of the X-ray spectrum varied during the observation, such that the hard X-rays always led the soft X-rays, both in brightening and dimming of the source, with a lag of the 0.5-1 keV photons versus those in the 2-7.5 keV band of similar to 1 hr. The rapid TeV variability indicates a compact TeV-producing region, suggesting relativistic beaming with a Doppler factor delta greater than or equal to 5. The correlation of the flux in the X-ray and the TeV bands indicates that a high-energy tail of a single electron population is responsible for both X-rays and TeV gamma-rays, with radio, IR, UV and X-rays produced via the synchrotron process and GeV and TeV gamma-rays produced via Comptonization. Under the assumption that the ''soft lag'' observed in the X-ray band is due to the synchrotron-lifetime effects, with delta = 5, we calculate the magnetic field for the X-ray-producing region to be similar to 0.2 G. The Lorentz factors gamma(el) of the electrons responsible for the emission in the keV and TeV bands are similar to 10(6), consistent with the values implied by the Klein-Nishina limit.

  • ASCA observation of an X-ray/TeV flare from the BL Lacertae object Markarian 421

    T Takahashi, M Tashiro, G Madejski, H Kubo, T Kamae, J Kataoka, T Kii, F Makino, K Makishima, N Yamasaki

    ASTROPHYSICAL JOURNAL   470 ( 2 ) L89 - L92  1996.10

     View Summary

    We observed the BL Lac object Mrk 421 with the X-ray satellite ASCA in 1994 as part of a multifrequency observation. The 24 hr observation was conducted 1 day after the onset of a TeV flare detected by the Whipple Observatory and detected an X-ray flare, with no apparent variability in the optical, UV, and EGRET GeV flux. The ASCA 2-10 keV flux peaked at 3.7 x 10(-10) ergs cm(-2) s(-1) and then decreased to 1.8 x 10(-10) ergs cm(-2) s(-1) with a doubling timescale of similar to 12 hr. The shape of the X-ray spectrum varied during the observation, such that the hard X-rays always led the soft X-rays, both in brightening and dimming of the source, with a lag of the 0.5-1 keV photons versus those in the 2-7.5 keV band of similar to 1 hr. The rapid TeV variability indicates a compact TeV-producing region, suggesting relativistic beaming with a Doppler factor delta greater than or equal to 5. The correlation of the flux in the X-ray and the TeV bands indicates that a high-energy tail of a single electron population is responsible for both X-rays and TeV gamma-rays, with radio, IR, UV and X-rays produced via the synchrotron process and GeV and TeV gamma-rays produced via Comptonization. Under the assumption that the ''soft lag'' observed in the X-ray band is due to the synchrotron-lifetime effects, with delta = 5, we calculate the magnetic field for the X-ray-producing region to be similar to 0.2 G. The Lorentz factors gamma(el) of the electrons responsible for the emission in the keV and TeV bands are similar to 10(6), consistent with the values implied by the Klein-Nishina limit.

    DOI

  • ASCA Observations of X-ray/TeV Flare from Mkn 421

    Takahashi et a

    Mem. Della Soc.Astr. Ital.   67   533  1996

  • ASCA Observations of X-ray/TeV Flare from Mkn 421

    Takahashi et a

    Mem. Della Soc.Astr. Ital.   67   533  1996

  • A SEARCH FOR MASSIVE NEUTRAL BOSONS IN ORTHOPOSITRONIUM DECAY

    T MAENO, M FUJIKAWA, J KATAOKA, Y NISHIHARA, S ORITO, K SHIGEKUNI, Y WATANABE

    PHYSICS LETTERS B   351 ( 4 ) 574 - 578  1995.06

     View Summary

    We have searched for an exotic decay of orthopositronium into a single photon and a short-lived neutral boson in the hitherto unexplored mass region above 900 keV/c(2), by noting that this decay is one of few remaining candidates which could explain the discrepancy of the orthopositronium decay rate. A high-resolution measurement of the associated photon energy spectrum was carried out with a germanium detector to search for a sharp peak from this two-body decay. Our negative result provides an upper limit of 2.0 x 10(-4) on the branching ratio of such a decay in the mass region from 847 to 1013 keV/c(2), and excludes the possibility of this decay mode explaining the discrepancy in the orthopositronium decay rate.

    DOI CiNii

  • Temperature effects in reverse-type avalanche photodiodes

    Mitsuhiro Sato, Takayuki Yanagida, Akira Yoshikawa, Yoichi Yatsu, Jun Kataoka, Fumio Saito

    2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11     1491 - +  1905.06  [Refereed]

     View Summary

    These The present paper shows ionization coefficient ratios, k-values, k(1) and k(eff), of reverse-type Si avalanche photodiode. Both of k(eff) and k(1), tend to increase when APDs are cooled down. The results for k(eff) are 0.0023 +/- 0.0002 at 20 degrees C, 0.0027 +/- 0.0003 at 0 degrees C, and 0.0049 +/- 0.0007 at -20 degrees C. With the result of k(1), temperature dependency of k-values indicates mean free paths of the carriers for phonon scattering shows different temperature dependency, which is considered to reflect the inner structure of APDs.

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Industrial Property Rights

  • 放射性物質の三次元分布を計測する方法及びその装置

    片岡 淳, 岩本 康弘, 岸本 彩

    Patent

  • コンプトンカメラ

    6191957

    片岡 淳, 西山 徹

    Patent

  • コンプトンカメラ

    5991519

    岸本 彩, 加藤 卓也, 片岡 淳

    Patent

  • 放射線検出器

    6145248

    片岡 淳, 岸本 彩

    Patent

  • 携帯型放射線検出器

    片岡 淳

    Patent

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  • Scientific...

     View Summary

    Scientific Organizing Committe for
    (1) "15-years of Chandra", Nov. Harvard Center for Astrophysics, Boston, USA, Nov, 2014
    (2) "The Many Faces of Centaurus A",r June-July 2009, Sydney, Australia
    (3) "Radio Galaxies in Chandra Era", July, 2008, Cambridge, USA
    (4) "Workshop on Blazar Variability across the Electromagnetic Spectrum", Apri, 2008, Paris, France

 

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Sub-affiliation

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

Research Institute

  • 2022
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    2024

    Waseda Research Institute for Science and Engineering   Concurrent Researcher