Concurrent Post

Faculty of Science and Engineering School of Advanced Science and Engineering
Details of a Researcher
Updated on 2022/05/18
Faculty of Science and Engineering School of Advanced Science and Engineering
Waseda University Institue for Advanced Study
Waseda University Institue for Advanced Study
Waseda University Research Institute for Science and Engineering
Kyoto University Yukawa Institute for Theoretical Physics
Waseda University Research Institute for Science and Engineering
Institute Superior Tecnico GRIT ERC fellow
Kyoto University Yukawa Institute for Theoretical Physics Research Physics under Extreme Conditions
Theoretical studies related to particle, nuclear, cosmic ray and astrophysics General Relativity
Computational Science
Astrophysics
ECOspotting: Looking for extremely compact objects with bosonic fields
Vitor Cardoso, Caio F.B. Macedo, Kei Ichi Maeda, Hirotada Okawa
Classical and Quantum Gravity 39 ( 3 ) 2022.02
Multidimensional Boltzmann Neutrino Transport Code in Full General Relativity for Corecollapse Simulations
Ryuichiro Akaho, Akira Harada, Hiroki Nagakura, Kohsuke Sumiyoshi, Wakana Iwakami, Hirotada Okawa, Shun Furusawa, Hideo Matsufuru, Shoichi Yamada
Astrophysical Journal 909 ( 2 ) 2021.03
PostNewtonian KozaiLidov mechanism and its effect on cumulative shift of periastron time of binary pulsar
Haruka Suzuki, Priti Gupta, Hirotada Okawa, Kei Ichi Maeda
Monthly Notices of the Royal Astronomical Society 500 ( 2 ) 1645  1665 2021.01
Simulations of the early postbounce phase of corecollapse supernovae in threedimensional space with full boltzmann neutrino transport
Wakana Iwakami, Hirotada Okawa, Hiroki Nagakura, Akira Harada, Shun Furusawa, Kosuke Sumiyoshi, Hideo Matsufuru, Shoichi Yamada
Astrophysical Journal 903 ( 2 ) 2020.11
The Boltzmannradiationhydrodynamics Simulations of Corecollapse Supernovae with Different Equations of State: The Role of Nuclear Composition and the Behavior of Neutrinos
Akira Harada, Hiroki Nagakura, Wakana Iwakami, Hirotada Okawa, Shun Furusawa, Kohsuke Sumiyoshi, Hideo Matsufuru, Shoichi Yamada
Astrophysical Journal 902 ( 2 ) 2020.10
Threshold of primordial black hole formation in nonspherical collapse
Chul Moon Yoo, Tomohiro Harada, Hirotada Okawa
Physical Review D 102 ( 4 ) 2020.08
Gravitational waves from hierarchical triple systems with KozaiLidov oscillation
Priti Gupta, Haruka Suzuki, Hirotada Okawa, Kei Ichi Maeda
Physical Review D 101 ( 10 ) 2020.05 [Refereed]
Fast collective neutrino oscillations inside the neutrino sphere in corecollapse supernovae
M. Delfan Azari, S. Yamada, T. Morinaga, H. Nagakura, S.Furusawa, A. Harada, H. Okawa, W. Iwakami, K. Sumiyoshi
Physical Review D 101 ( 2 ) 2020.01
Cumulative shift of periastron time of binary pulsar with Kozai–Lidov oscillation
Haruka Suzuki, Priti Gupta, Hirotada Okawa, Kei Ichi Maeda
Monthly Notices of the Royal Astronomical Society: Letters 486 ( 1 ) L52  L57 2019.06 [Refereed]
Linear analysis of fastpairwise collective neutrino oscillations in corecollapse supernovae based on the results of Boltzmann simulations
Milad Delfan Azari, Shoichi Yamada, Taiki Morinaga, Wakana Iwakami, Hirotada Okawa, Hiroki Nagakura, Kohsuke Sumiyoshi
Physical Review D 99 ( 10 ) 2019.05 [Refereed]
Gravitational collapse of a massless scalar field in a periodic box
Chul Moon Yoo, Taishi Ikeda, Hirotada Okawa
Classical and Quantum Gravity 36 ( 7 ) 2019.03 [Refereed]
Akira Harada, Hiroki Nagakura, Wakana Iwakami, Hirotada Okawa, Shun Furusawa, Hideo Matsufuru, Kohsuke Sumiyoshi, Shoichi Yamada
Astrophysical Journal 872 ( 2 ) 2019 [Refereed]
Effects of Rotation and Magnetic Field on the Revival of a Stalled Shock in Supernova Explosions
Kotaro Fujisawa, Hirotada Okawa, Yu Yamamoto, Shoichi Yamada
Astrophysical Journal 872 ( 2 ) 2019 [Refereed]
Akira Harada, Hiroki Nagakura, Wakana Iwakami, Hirotada Okawa, Shun Furusawa, Hideo Matsufuru, Kohsuke Sumiyoshi, Shoichi Yamada
2018.10
Maximal efficiency of the collisional Penrose process with spinning particles
Kei Ichi Maeda, Kazumasa Okabayashi, Hirotada Okawa
Physical Review D 98 ( 6 ) 2018.09 [Refereed]
Effects of rotation and magnetic field on the revival of a stalled shock in supernova explosions
Kotaro Fujisawa, Hirotada Okawa, Yu Yamamoto, Shoichi Yamada
2018.09
The W4 method: a new multidimensional rootfinding scheme for nonlinear systems of equations
Hirotada Okawa, Kotaro Fujisawa, Yu Yamamoto, Ryosuke Hirai, Nobutoshi Yasutake, Hiroki Nagakura, Shoichi Yamada
2018.09
Hiroki Nagakura, Wakana Iwakami, Shun Furusawa, Hirotada Okawa, Akira Harada, Kohsuke Sumiyoshi, Shoichi Yamada, Hideo Matsufuru, Akira Imakura
Astrophysical Journal 854 ( 2 ) 2018.02 [Refereed]
Katsuki Aoki, Kei Ichi Maeda, Yosuke Misonoh, Hirotada Okawa
Physical Review D 97 ( 4 ) 2018.02 [Refereed]
Hydrostatic Equilibria of Rotating Stars with Realistic Equation of State
Nobutoshi Yasutake, Kotaro Fujisawa, Hirotada Okawa, Shoichi Yamada
JPS Conf.Proc. 20 17pp 2018 [Refereed]
Nonlinear collisional Penrose process: How much energy can a black hole release?
Ken Ichi Nakao, Hirotada Okawa, Kei Ichi Maeda
Progress of Theoretical and Experimental Physics 2018 ( 1 ) 2018.01 [Refereed]
3D simulation of spindle gravitational collapse of a collisionless particle system
Chul Moon Yoo, Tomohiro Harada, Hirotada Okawa
Classical and Quantum Gravity 34 ( 10 ) 2017.04 [Refereed]
Hyperbolic selfgravity solver for large scale hydrodynamical simulations
Ryosuke Hirai, Hiroki Nagakura, Hirotada Okawa, Kotaro Fujisawa
Physical Review D 93 ( 8 ) 2016.04 [Refereed]
Interaction between bosonic dark matter and stars
Richard Brito, Vitor Cardoso, Caio F.B. Macedo, Hirotada Okawa, Carlos Palenzuela
Physical Review D 93 ( 4 ) 2016.02 [Refereed]
Testing general relativity with present and future astrophysical observations
Emanuele Berti, Enrico Barausse, Vitor Cardoso, Leonardo Gualtieri, Paolo Pani, Ulrich Sperhake, Leo C. Stein, Norbert Wex, Kent Yagi, Tessa Baker, C. P. Burgess, Flávio S. Coelho, Daniela Doneva, Antonio De Felice, Pedro G. Ferreira, Paulo C.C. Freire, James Healy, Carlos Herdeiro, Michael Horbatsch, Burkhard Kleihaus, Antoine Klein, Kostas Kokkotas, Jutta Kunz, Pablo Laguna, Ryan N. Lang, Tjonnie G.F. Li, Tyson Littenberg, Andrew Matas, Saeed Mirshekari, Hirotada Okawa, Eugen Radu, Richard O'Shaughnessy, Bangalore S. Sathyaprakash, Chris Van Den Broeck, Hans A. Winther, Helvi Witek, Mir Emad Aghili, Justin Alsing, Brett Bolen, Luca Bombelli, Sarah Caudill, Liang Chen, Juan Carlos Degollado, Ryuichi Fujita, Caixia Gao, Davide Gerosa, Saeed Kamali, Hector O. Silva, João G. Rosa, Laleh Sadeghian, Marco Sampaio, Hajime Sotani, Miguel Zilhao
Classical and Quantum Gravity 32 ( 24 ) 2015.12
Nonlinear evolutions of bosonic clouds around black holes
Hirotada Okawa
Classical and Quantum Gravity 32 ( 21 ) 2015.10 [Refereed]
Accretion of Dark Matter by Stars
Richard Brito, Vitor Cardoso, Hirotada Okawa
Physical Review Letters 115 ( 11 ) 2015.09 [Refereed]
Dynamical mass ejection from black holeneutron star binaries
Koutarou Kyutoku, Kunihito Ioka, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
Physical Review D  Particles, Fields, Gravitation and Cosmology 92 ( 4 ) 2015.08 [Refereed]
Evidence for event horizons: Longlived modes in ultracompact objects
Caio F.B. MacEdo, Luís C.B. Crispino, Vitor Cardoso, Hirotada Okawa, Paolo Pani
International Journal of Modern Physics D 24 ( 9 ) 2015.08 [Refereed]
Dynamical mass ejection from black holeneutron star binaries
Koutarou Kyutoku, Kunihito Ioka, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
PHYSICAL REVIEW D 92 ( 4 ) 2015.08 [Refereed]
Kyohei Kawaguchi, Koutarou Kyutoku, Hiroyuki Nakano, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
Physical Review D  Particles, Fields, Gravitation and Cosmology 92 ( 2 ) 2015.07 [Refereed]
Black holeneutron star binary merger: Dependence on black hole spin orientation and equation of state
Kyohei Kawaguchi, Koutarou Kyutoku, Hiroyuki Nakano, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
PHYSICAL REVIEW D 92 ( 2 ) 2015.07 [Refereed]
Kenta Hotokezaka, Koutarou Kyutoku, Hirotada Okawa, Masaru Shibata
Physical Review D  Particles, Fields, Gravitation and Cosmology 91 ( 6 ) 2015.03 [Refereed]
Exploring tidal effects of coalescing binary neutron stars in numerical relativity. II. Longterm simulations
Kenta Hotokezaka, Koutarou Kyutoku, Hirotada Okawa, Masaru Shibata
PHYSICAL REVIEW D 91 ( 6 ) 2015.03 [Refereed]
Black holes and fundamental fields: Hair, kicks, and a gravitational Magnus effect
Hirotada Okawa, Vitor Cardoso
Physical Review D  Particles, Fields, Gravitation and Cosmology 90 ( 10 ) 2014.11 [Refereed]
Study of the nonlinear instability of confined geometries
Hirotada Okawa, Vitor Cardoso, Paolo Pani
Physical Review D  Particles, Fields, Gravitation and Cosmology 90 ( 10 ) 2014.11 [Refereed]
Higher dimensional numerical relativity: Code comparison
Helvi Witek, Hirotada Okawa, Vitor Cardoso, Leonardo Gualtieri, Carlos Herdeiro, Masaru Shibata, Ulrich Sperhake, Miguel Zilhão
Physical Review D  Particles, Fields, Gravitation and Cosmology 90 ( 8 ) 2014.10 [Refereed]
Vitor Cardoso, Luís C.B. Crispino, Caio F.B. Macedo, Hirotada Okawa, Paolo Pani
Physical Review D  Particles, Fields, Gravitation and Cosmology 90 ( 4 ) 2014.08 [Refereed]
Black hole universe with a cosmological constant
Chul Moon Yoo, Hirotada Okawa
Physical Review D  Particles, Fields, Gravitation and Cosmology 89 ( 12 ) 2014.06 [Refereed]
Hirotada Okawa, Helvi Witek, Vitor Cardoso
Physical Review D  Particles, Fields, Gravitation and Cosmology 89 ( 10 ) 2014.05 [Refereed]
Black holes and fundamental fields in numerical relativity: Initial data construction and evolution of bound states
Hirotada Okawa, Helvi Witek, Vitor Cardoso
PHYSICAL REVIEW D 89 ( 10 ) 2014.05 [Refereed]
Coalescence of binary neutron stars in a scalartensor theory of gravity
Masaru Shibata, Keisuke Taniguchi, Hirotada Okawa, Alessandra Buonanno
Physical Review D  Particles, Fields, Gravitation and Cosmology 89 ( 8 ) 2014.04 [Refereed]
Hirotada Okawa, Vitor Cardoso, Paolo Pani
Physical Review D  Particles, Fields, Gravitation and Cosmology 89 ( 4 ) 2014.02 [Refereed]
An alternative numerical method for the stationary pulsar magnetosphere
Yohsuke Takamori, Hirotada Okawa, Makoto Takamoto, Yudai Suwa
Publications of the Astronomical Society of Japan 66 ( 1 ) 2014 [Refereed]
Blackhole universe: Time evolution
Chul Moon Yoo, Hirotada Okawa, Ken Ichi Nakao
Physical Review Letters 111 ( 16 ) 2013.10 [Refereed]
Hirotada Okawa
International Journal of Modern Physics A 28 ( 2223 ) 2013.09 [Refereed]
Mass ejection from the merger of binary neutron stars
Kenta Hotokezaka, Kenta Kiuchi, Koutarou Kyutoku, Hirotada Okawa, Yu Ichiro Sekiguchi, Masaru Shibata, Keisuke Taniguchi
Physical Review D  Particles, Fields, Gravitation and Cosmology 87 ( 2 ) 2013.01 [Refereed]
NR/HEP: Roadmap for the future
Vitor Cardoso, Leonardo Gualtieri, Carlos Herdeiro, Ulrich Sperhake, Paul M. Chesler, Luis Lehner, Seong Chan Park, Harvey S. Reall, Carlos F. Sopuerta, Daniela Alic, Oscar J.C. Dias, Roberto Emparan, Valeria Ferrari, Steven B. Giddings, Mahdi Godazgar, Ruth Gregory, Veronika E. Hubeny, Akihiro Ishibashi, Greg Landsberg, Carlos O. Lousto, David Mateos, Vicki Moeller, Hirotada Okawa, Paolo Pani, M. Andy Parker, Frans Pretorius, Masaru Shibata, Hajime Sotani, Toby Wiseman, Helvi Witek, Nicolas Yunes, Miguel Zilhão
Classical and Quantum Gravity 29 ( 24 ) 2012.12 [Refereed]
Koutarou Kyutoku, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
Physical Review D  Particles, Fields, Gravitation and Cosmology 84 ( 6 ) 2011.09 [Refereed]
Gravitational waves from spinning black holeneutron star binaries: dependence on black hole spins and on neutron star equations of state
Koutarou Kyutoku, Hirotada Okawa, Masaru Shibata, Keisuke Taniguchi
PHYSICAL REVIEW D 84 ( 6 ) 2011.09 [Refereed]
Binary neutron star mergers: Dependence on the nuclear equation of state
Kenta Hotokezaka, Koutarou Kyutoku, Hirotada Okawa, Masaru Shibata, Kenta Kiuchi
Physical Review D  Particles, Fields, Gravitation and Cosmology 83 ( 12 ) 2011.06 [Refereed]
Is superPlanckian physics visible? Scattering of black holes in 5 dimensions
Hirotada Okawa, Ken Ichi Nakao, Masaru Shibata
Physical Review D  Particles, Fields, Gravitation and Cosmology 83 ( 12 ) 2011.06 [Refereed]
Highvelocity bh collision in 5 dimensions
Hirotada Okawa, Masaru Shibata
Proceedings of the 20th Workshop on General Relativity and Gravitation in Japan, JGRG 2010 425  427 2010.12
Highvelocity bh collision in 5 dimensions
Hirotada Okawa, Masaru Shibata
Proceedings of the 20th Workshop on General Relativity and Gravitation in Japan, JGRG 2010 425  427 2010 [Refereed]
Gravitational waves from spinning black holeneutron star binaries
Koutarou Kyutoku, Masaru Shibata, Hirotada Okawa, Keisuke Taniguchi
Proceedings of the 20th Workshop on General Relativity and Gravitation in Japan, JGRG 2010 254  257 2010 [Refereed]
Highvelocity collision of two black holes
Masaru Shibata, Hirotada Okawa, Tetsuro Yamamoto
Physical Review D  Particles, Fields, Gravitation and Cosmology 78 ( 10 ) 2008.11 [Refereed]
A new multidimensional root finder for a system of nonlinear equations
Hirotada Okawa Web Service
General relativistic rotating stars for evolution in the Lagrangian description
Japan Society for the Promotion of Science GrantsinAid for Scientific Research GrantinAid for Scientific Research (C)
Project Year :
Theoretical study of the mass and angular momentum distribution of primordial black holes
Japan Society for the Promotion of Science GrantsinAid for Scientific Research GrantinAid for Scientific Research (B)
Project Year :
Development of a Novel Numerical Scheme for Multidimensional Stellar Evolution Calculations
Japan Society for the Promotion of Science GrantsinAid for Scientific Research GrantinAid for Challenging Research (Exploratory)
Project Year :
YAMADA Shoichi
Eccentric KozaiLidov Mechanism and Orbital Flip
Hirotada Okawa
Waseda Astrophysics Group Colloquium
Presentation date： 2021.11
ラグランジュ描像における相対論的回転星の進化計算
大川博督, 藤澤幸太郎, 安武伸俊, 小形美沙, 山本佑, 山田章一
日本物理学会２０２１年秋季大会
Presentation date： 2021.09
新しい非線形連立方程式の解法（W4法）を用いた非線形楕円型方程式の解析手法の確立
大川博督
WIAS Research Debriefing Session
Presentation date： 2021.07
Lagrange Construction of Relativistic Rotating Stars
Hirotada Okawa
Waseda Spring Interim Report
Presentation date： 2021.04