Wave optical effect in black hole spacetimes

• Project/Area Number: 15K05073
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Nagoya University
• Principal Investigator: Nambu Yasusada 名古屋大学, 理学研究科, 准教授 (40212112)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
• Keywords: ブラックホール / 光の不安定軌道 / 波動光学 / 干渉と回折 / wave optics / black hole / photon sphere / ブラックホール時空での波動光学 / 重力レンズ / Regge pole

Outline of Final Research Achievements

To discriminate black hole mimikers of which radius is smaller than unstable photon orbit, we investigate wave optics in spherically symmetric spacetimes with compact gravitating object. We found that the effect of star's surface smaller than the radius of unstable photon orbit results in oscillation in power spectrums with long period, which make possible to discriminate black hole mimickers from black hole.

Academic Significance and Societal Importance of the Research Achievements

光の不安定軌道より半径が小さい天体(black hole mimicker)は，天体自身が光を放出しない完全吸収表面を持つ場合には，外部から照らす光を用いては black holeと区別することはできない．しかしながら波動を用いたそのような天体からの散乱波の観測が可能であれば，表面の存在は散乱波のパワースペクトルに周期の長い振動を生じさせる．これは遠方を通る波と星の表面の存在による回析効果の結果である．不安定軌道の存在そのものは，パワスペクトルに対して短い周期の振動を生じさせるので，これらの２種類の振動パターンを解析することで，光では見えない不安定軌道内部の情報を引き出すことが可能となる．

Research Products

• [Journal Article] Analog rotating black hole in a magnetohydrodynamic inflow (2017)
  • Author(s): S. Noda, Y. Nambu and M. Takahashi
  • Journal Title: Phys. Rev. D Volume: 95 Pages: 104055-104055
  • Peer Reviewed
• [Journal Article] Analogu Kerr-like geometries in a MHD flow (2017)
  • Author(s): S. Noda, Y. Nambu, M. Takahashi
  • Journal Title: Proceedings of JGRG26 Volume: -
• [Journal Article] Spherical polytropic balls cannot mimic black holes (2016)
  • Author(s): H. Saida, A. Fujiwara, C. Yoo and Y. Nambu
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2016
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Wave optics in black hole spacetimes: the Schwarzschild case (2016)
  • Author(s): Yasusada Nambu and Sosuke Noda
  • Journal Title: Class. Quantum Grav. Volume: 33 Pages: 075011-075011
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Spherical polytropic balls cannot minic black hole (2016)
  • Author(s): Hiromi Saida, Atuhito Fujisama, Chul-moon Yoo, Yasusada Nambu
  • Journal Title: Prog. Theor. and Exper. Phys, Volume: ?
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Maximu mass of a barotropic sphericall star (2015)
  • Author(s): Atuhito Fujisama,, Hiromi Saida, Chul-moon Yoo, Yasusada Nambu
  • Journal Title: Class. Quantum Grav. Volume: 32 Pages: 215028-215028
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Wave optics in spacetimes with compact gravitating object (2019)
  • Author(s): 南部保貞
  • Organizer: 磁気圏研究会
  • Invited
• [Presentation] BZ processとsuperradiance (2018)
  • Author(s): 南部保貞
  • Organizer: BZ研究会
  • Invited
• [Presentation] 波動光学を用いたブラックホールの撮像 (2018)
  • Author(s): Y. Nambu
  • Organizer: ブラックホール磁気圏研究会
  • Invited
• [Presentation] ブラックホール擬似天体による波の散乱問題とシャドー (2017)
  • Author(s): S. Noda, Y. Nambu
  • Organizer: 日本物理学会
  • Place of Presentation: 大阪大学
  • Year and Date: 2017-03-17
• [Presentation] カー時空での波動光学の数値計算 (2017)
  • Author(s): Y. Nambu
  • Organizer: ブラックホール磁気圏研究会
  • Place of Presentation: 南紀白浜ホテル三楽荘
  • Year and Date: 2017-03-03
  • Invited
• [Presentation] BZ process と sueprradiance (2017)
  • Author(s): Y. Nambu
  • Organizer: BZ研究会
  • Invited
• [Presentation] Analogu Kerr-like geometries in a MHD flow (2016)
  • Author(s): S. Noda, Y. Nambu, M. Takahashi
  • Organizer: JGRG26
  • Place of Presentation: 大阪市立大
  • Year and Date: 2016-10-27
  • Int'l Joint Research
• [Presentation] Particle limit and superradiance (2016)
  • Author(s): Y. Nambu
  • Organizer: M87 Workshop
  • Place of Presentation: 台湾大学 ASIAA
  • Year and Date: 2016-05-23
  • Int'l Joint Research
• [Presentation] Kerr時空上の波動光学とパワースペクトルにおけるうなり (2016)
  • Author(s): Sousuke Noda and Yasusada Nambu
  • Organizer: 日本物理学会
  • Place of Presentation: 東北学院大学
  • Year and Date: 2016-03-19
• [Presentation] Wave optics in the Kerr spacetime and black hole shadows (2015)
  • Author(s): Sousuke Noda and Yasusada Nambu
  • Organizer: JGRG25
  • Place of Presentation: 京都大学
  • Year and Date: 2015-12-07
  • Int'l Joint Research
• [Presentation] Kerr時空上の波動光学とブラックホールシャドー (2015)
  • Author(s): Sousuke Noda and Yasusada Nambu
  • Organizer: 日本物理学会
  • Place of Presentation: 大阪市立大学
  • Year and Date: 2015-09-26
• [Presentation] Wave optics in the Kerr spacetime and black hole shadows (2015)
  • Author(s): Sousuke Noda and Yasusada Nambu
  • Organizer: Hot topics in general relativity and gravitation
  • Place of Presentation: Quy Nhon, Vietnam
  • Year and Date: 2015-08-12
  • Int'l Joint Research