Submitted Papers

  • Takatoshi Ko, Hiromasa Suzuki, Kazumi Kashiyama, Hiroyuki Uchida, Takaaki Tanaka, Daichi Tsuna, Kotaro Fujisawa, Aya Bamba, Toshikazu Shigeyama
    submitted [ ADS ] [ arXiv:2304.14669 ]
    "A dynamical model for IRAS 00500+6713: the remnant of a type Iax supernova SN 1181 hosting a double degenerate merger product WD J005311"

  • Soichiro Yamazaki, Fumio Uchida, Kotaro Fujisawa, Naoki Yoshida
    submitted [ ADS ] [ arXiv:2303.16490 ]
    "Quantum algorithm for collisionless Boltzmann simulation of self-gravitating systems"

  • Hirotada Okawa, Kotaro Fujisawa, Yu Yamamoto, Nobutoshi Yasutake, Misa Ogata, Shoichi Yamada,
    submitted [ ADS ] [ arXiv:2204.09941 ]
    "Singularity-Avoiding Multi-Dimensional Root-Finder"

    • Refereed Papers

    My all papers in ADS and in arXiv.

      2023

    1. Koji Uryu, Shijun Yoshida, Eric Gourgoulhon, Charalampos Markakis, Kotaro Fujisawa, Antonios Tsokaros, Keisuke Taniguchi, Mina Zamani, 2023
      Physical Review D, in press, [ ADS ] [ arXiv ]
      "Equilibriums of extremely magnetized compact stars with force-free magnetotunnels"

    2. Yasufumi Kojima, Shota Kisaka, Kotaro Fujisawa, 2023
      The Astrophysical Journal, 946, 75, [ ADS ] [ arXiv ]
      "Evolutionary deformation toward the elastic limit by a magnetic field confined in the neutron star crust"

    3. Misa Ogata, Hirotada Okawa, Kotaro Fujisawa, Nobutoshi Yasutake, Yu Yamamoto, Shoichi Yamada, 2023
      MNRAS, 521(2), 2561--2576, [ ADS ] [ arXiv:2210.09501 ]
      "A Lagrangian construction of rotating star models"

    4. Hirotada Okawa, Kotaro Fujisawa, Nobutoshi Yasutake, Misa Ogata, Yu Yamamoto, Shoichi Yamada, 2023
      MNRAS, 520(1), 24--43, [ ADS ] [ arXiv:2204.09943 ]
      "A novel Lagrangian formulation to construct relativistic rotating stars: towards its application to their evolution calculations"

    5. Kotaro Fujisawa, Yasufumi Kojima, Shota Kisaka, 2023
      MNRAS, 519, 3776--3784 [ ADS ] [ arXiv ]
      "Strong toroidal magnetic fields sustained by the elastic crust in a neutron star"

    6. Hirotada Okawa, Kotaro Fujisawa , Yu Yamamoto, Ryosuke Hirai, Nobutoshi Yasutake, Hiroki Nagakura, Shoichi Yamada, 2023
      Applied Numerical Mathematics 183, p.157-172 [ ADS ] [ arXiv:1809:04495 ]
      "The W4 method: a new multi-dimensional root-finding scheme for nonlinear systems of equations"

      7. 2022

    7. Yasushi Suto, Shin Sasaki, Masataka Aizawa, Kotaro Fujisawa, Kazumi Kashiyama, 2022
      Publications of the Astronomical Society of Japan [ ADS ] [ arXiv ]
      "Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: Application to light curves of white dwarfs"

    8. Takatoshi Ko, Kotaro Fujisawa, Toshikazu Shigeyama, 2022
      ApJ, 941, 38 [ ADS ] [ arXiv ]
      "Self-similar Solution of Rotating Eruptive Outflows on Its Equatorial Plane "

    9. Kotaro Fujisawa, Shota Kisaka, Yasufumi Kojima, 2022
      MNRAS, 516, 5196--5208 [ ADS ] [ arXiv ]
      "Magnetically confined mountains on accreting neutron stars with multipole magnetic fields"

    10. Masataka Aizawa, Kojiro Kawana, Kazumi Kashiyama, Ryou Ohsawa, Hajime Kawahara, Fumihiro Naokawa, Tomoyuki Tajiri, Noriaki Arima, Hanchun Jiang, Tilman Hartwig, Kotaro Fujisawa, Toshikazu Shigeyama, Ko Arimatsu, Mamoru Doi, Toshihiro Kasuga, Naoto Kobayashi, Sohei Kondo, Yuki Mori, Shin-ichiro Okumura, Satoshi Takita, Shigeyuki Sako, 2022
      PASJ, 74, 5, pp.1069-1094 [ ADS ] [ arXiv ]
      "Fast optical flares from M dwarfs detected by a one-second-cadence survey with Tomo-e Gozen"

    11. Yasufumi Kojima, Shota Kisaka, Kotaro Fujisawa, 2022
      MNRAS, 511, 480--487 [ ADS ] [ arXiv ]
      "Magnetic field sustained by the elastic force in neutron star crusts"

      12. 2021

    12. Yasufumi Kojima, Shota Kisaka, Kotaro Fujisawa, 2021
      MNRAS, 506, 3936--3945 [ ADS ] [ arXiv ]
      "Magneto-elastic equilibrium of a neutron star crust"

    13. Yasufumi Kojima, Shota Kisaka, Kotaro Fujisawa, 2021
      MNRAS, 502, 2097--2104 [ ADS ] [ arXiv ]
      "Evolution of magnetic deformation in neutron star crust"

      14. 2019

    14. Koji Uryu, Shijun Yoshida, Eric Gourgoulhon, Charalampos Markakis, Kotaro Fujisawa, Antonios Tsokaros, Keisuke Taniguchi, and Yoshiharu Eriguchi, 2019
      Phys. Rev. D 100, 123019 [ ADS ] [ arXiv ]
      "New code for equilibriums and quasiequilibrium initial data of compact objects. IV. Rotating relativistic stars with mixed poloidal and toroidal magnetic fields "

    15. Kazumi Kashiyama, Kotaro Fujisawa, Toshikazu Shigeyama
      ApJ 887, 39, 8 [ ADS ] [ arXiv ]
      " The Optically Thick Rotating Magnetic Wind from a Massive White Dwarf Merger Product"

    16. Kotaro Fujisawa, Hirotada Okawa, Yu Yamamoto, Shoichi Yamada, 2019
      ApJ 872, 155, 17 [ ADS ] [ arXiv ]
      "Effects of rotation and magnetic field on the revival of a stalled shock in supernova explosions"

      17. 2016

    17. Nobutoshi Yasutake, Kotaro Fujisawa , Shoichi Yamada, 2016
      MNRAS, 463, 3705-3724 [ ADS ] [ arXiv ]
      "Rotational equilibria by Lagrangian variational principle: towards multidimensional stellar evolutions"

    18. Ryosuke Hirai, Hiroki Nagakura, Hirotada Okawa, Kotaro Fujisawa , 2016
      Phys. Rev. D, 93, 083006 [ ADS ] [ arXiv ]
      "Hyperbolic Self-Gravity Solver for Large Scale Hydrodynamical Simulations"

      19. 2015

    19. Kotaro Fujisawa , 2015
      MNRAS, 454, 3060-3072 [ ADS ] [ arXiv ]
      "A versatile numerical method for obtaining structures of rapidly rotating baroclinic stars: self-consistent and systematic solutions with shellular-type rotation"

    20. Kotaro Fujisawa , 2015
      MNRAS, 450, 4016-4024 [ ADS ] [ arXiv ]
      "Magnetized stars with differential rotation and a differential toroidal field"

    21. Kotaro Fujisawa and Yoshiharu Eriguchi, 2015
      PASJ, 67(3):53 [ ADS ] [ arXiv ]
      "Appearance of the prolate and the toroidal magnetic field dominated stars - Analytic approach"

    22. Nobutoshi Yasutake, Kotaro Fujisawa, Shoichi Yamada, 2014
      MNRAS Letters, 446, L56. [ ADS ] [ arXiv ]
      "A Novel Formulation by Lagranginan Variational Principle for Rotational Equilibria: Toward Multi-Dimensional Stellar Evolutions"

      23. 2014

    23. Kotaro Fujisawa and Shota Kisaka, 2014
      MNRAS, 445, 2777-2793 [ ADS ] [ arXiv ]
      "Magnetic field configurations of a magnetar throughout its interior to exterior -- core, crust and magnetosphere"

    24. Koji Uryu, Eric Gourgoulhon, Charalampos Markakis, Kotaro Fujisawa, Antonios Tsokaros, Yoshiharu Eriguchi, 2014
      Phys. Rev. D 90, 101501(R) 2014 [ ADS ] [ arXiv ]
      "Equilibrium solutions of relativistic rotating stars with mixed poloidal and toroidal magnetic fields"

    25. Kotaro Fujisawa and Yoshiharu Eriguchi, 2014
      MNRAS Letters, 438, L61. [ ADS ] [ arXiv ]
      "Prolate stars due to meridional flows"

      26. 2013

    26. Kotaro Fujisawa and Yoshiharu Eriguchi, 2013
      MNRAS, 432, 1245. [ ADS ] [ arXiv ]
      "Coexistence of oppositely flowing multi-φ-currents: Key to large toroidal magnetic fields within stars"

    27. Kotaro Fujisawa, Rohta Takahashi, Shijun Yoshida and Yoshiharu Eriguchi, 2013
      MNRAS, 431, 1453. [ ADS ] [ arXiv ]
      "Counter effects of meridional flows and magnetic fields in stationary axisymmetric self-gravitating barotropes under the ideal MHD approximation: Clear examples ― toroidal configurations"

      28. 2012

    28. Kotaro Fujisawa, Shin'ichirou Yoshida and Yoshiharu Eriguchi, 2012
      MNRAS, 422, 434. [ ADS ] [ arXiv ]
      "Axisymmetric and stationary structures of magnetized barotropic stars with extremely strong magnetic fields deep inside"

    Presentations [International]

    1. "Rotational equilibria on the 2D Lagrange coordinates"
      2. Kotaro Fujisawa, Hirotada Okawa, Misa Ogata, Nobutoshi Yasutake, Yu Yamamoto & Shoichi Yamada
      The Evolution of Massive Stars and Formation of Compact Stars: from the Cradle to the Grave
      (2020.2.26 Waseda University, Tokyo, Japan) (Oral)

    2. "Effects of rotation and magnetic field on the revival of a stalled shock in supernova explosions"
      3. Kotaro Fujisawa, Hirotada Okawa, Yu Yamamoto & Shoichi Yamada
      Physics of Core-Collapse Supernovae and Compact Star Formations
      (2018.3.20 Waseda University, Tokyo, Japan) (Poster)

    3. "Rapidly rotating substellar objects"
      4. Kotaro Fujisawa & Yushi Sato
      Exoplanets and Planet Formation
      (2017.12.1 Shanghai, China) (Poster)

    4. "Magnetic field configurations of magnetars"
      5. Kotaro Fujisawa, Akihiro Yatabe & Shota Kisaka
      IAU Symposium 337 Pulsar Astrophysics: The Next Fifty Years
      (2017.9.3 Jodrell Bank Observatory, UK) (Poster)

    5. "Equilibrium structures of rapidly rotating massive stars with shellular rotation"
      6. Kotaro Fujisawa & Yu Yamamoto
      Phenomena, Physics, and Puzzles Of Massive Stars and their Explosive Outcomes
      (2017.3.20 Santa Barbara, USA) (Poster)

    6. "Magnetic field configurations of a magnetar throughout its interior and exterior"
      7. Kotaro Fujisawa & Shota Kisaka
      2nd Core-U International Conference: Cosmic Polarimetry from Micro to Macro Scales
      (2017.2.17 Hiroshima, Japan) (Poster)

    7. "Equilibrium structures of rapidly rotating stars with shellular rotation"
      8. Kotaro Fujisawa & Yu Yamamoto
      IAU Symposium 329 The lives and death-throes of massive stars
      (2016.11.28 Auckland, New Zealand) (Poster)

    8. "Magnetic field structures inside magnetars with strong toroidal field"
      9. Kotaro Fujisawa
      IAU Symposium 302 Magnetic Fields Throughout Stellar Evolution
      (2013.8.30 Biarritz, France) (Oral)

    9. "Axisymmetric and stationary magnetic field structures in neutron star crusts under various boundary conditions"
      10. Kotaro Fujisawa
      IAU Symposium 302 Magnetic Fields Throughout Stellar Evolution
      (2013.8.27 Biarritz, France) (Poster)

    10. "Let's solve GS equation!"
      11. Kotaro Fujisawa
      The Sixth Workshop on Black Hole Magnetospheres
      (2013.3.5 Hsinchu, Taiwan) (Oral)

    11. "Equilibrium states of magnetized disc-central compact object systems "
      12. Kotaro Fujisawa, Rohta Takahashi, Shijun Yoshida, Yoshiharu Eriguchi
      JGRG22       (2012.11.13 Tokyo, Japan) (Poster)

    12. "Stationary and Axisymmetric Magnetized Barotropic Stars with Various Field"
      13. Kotaro Fujisawa, Shin'ichiro Yoshida, Yoshiharu Eriguchi
      Magnetic Fields in the Universe III : From Laboratory and Stars to Primordial Structures (2011.8.23 Zakopane, Poland) (Poster)

    13. Stationary and Axisymmetric Configurations of Compact Stars with Extremely Strong and Highly Localized Magnetic Fields"
      14. Kotaro Fujisawa, Shin'ichiro Yoshida, Yoshiharu Eriguchi
      IAU Symposium 274 Advances in Plasma Astrophysics
      (2010.9.7 Giardini-Naxos, Sicilia, Italy) (talk)

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