Development of GRB polarimeter for elucidation of the radiation mechanism

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H02080
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Yamagata University
• Principal Investigator: Gunji Shuichi 山形大学, 理学部, 教授 (70241685)
• Co-Investigator(Kenkyū-buntansha): 中森 健之 山形大学, 理学部, 准教授 (30531876)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: ガンマ線バースト / 偏光度検出器 / コンプトン散乱

Outline of Final Research Achievements

The radiation mechanism of gamma rays from gamma ray bursts is still in the mystery. For the elucidation, the observation of the polarization is very useful. However, it is more difficult to detect the polarization of gamma rays than of visible light. Then utilizing the principle of anisotropy for Compton scattering, we have developed two types of Compton scattering polarimeters with high sensitivity and investigated the performance. The former one can only measure the two-dimensional scattering direction and the latter one can obtain the information on the three-dimensional scattering direction. It was recognized that the former one with geometrical area of 3000cm2 can elucidate the radiation mechanism of the gamma ray bursts in two years observation. For the latter one, we confirmed that it can operate as a Compton camera.

Free Research Field

高エネルギー宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

ガンマ線バーストは大変明るいので、その輻射メカニズムの詳細が分かると、遠方宇宙を探るための優れたプローブとなりうる。そのため、その輻射メカニズムを解明できるガンマ線バースト偏光度検出器の開発は宇宙論の分野において非常に重要である。今回我々が開発したプロトタイプ検出器を大型化すれば、輻射メカニズムの解明に大きく迫れるため、今後アメリカなどと共同でして、実際の衛星実験につなげていきたい。