2019 Fiscal Year Final Research Report
Study of gamma-ray bursts with optical near-infrared simultaneous polarimetry
| Project/Area Number |
15H02069
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | National Astronomical Observatory of Japan (2017-2019)
Hiroshima University (2015-2016) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
川端 弘治 広島大学, 宇宙科学センター, 教授 (60372702)
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| Project Period (FY) |
2015-04-01 – 2020-03-31
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| Keywords | 光赤外線天文学 / ガンマ線バースト / 偏光観測 / 高エネルギー天文学 |
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| Outline of Final Research Achievements |
We developed an astronomical instrument that can observe linearly polarized light from visible light to infrared light with one exposure to study the structure of the relativistic jet (plasma outflow flowing at a speed close to the speed of light) of gamma-ray burst, which is the most energetic explosion phenomenon in the universe. For this purpose, we developed a special polarization element called a wedged double Wollaston prism. We attached this instrument to the Kanata telescope of Hiroshima University, and performed simultaneous optical and infrared polarization observations for several gamma ray bursts. We revealed that the shock wave front propagates along spiral trajectory in the jet based on observations of the time variation of polarization of one gamma-ray burst immediately after the explosion. We also developed a low-noise, large-format near-infrared sensor for astronomy based on Indium-Gallium-Arsenicum composite material by collaboration with a Japanese manufacturer.
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| Free Research Field |
天文学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では、(1)可視光から赤外線まで一回の露出で偏光観測ができる天体観測装置を開発し、(2)これを用いてガンマ線バーストの初期偏光変動を観測して相対論的ジェットの構造の一部を明らかにし、さらに、(3)InGaAsベースの近赤外線センサーとして世界最高性能の低雑音かつ大フォーマットのセンサーの開発に成功した、という3つの成果を挙げている。開発した装置は宇宙における突発現象、特に時間変動の激しい現象の研究に新たな観測手段を加えるものである。また、InGaAs近赤外線センサーは、高性能センサーとして天体観測だけでなく、赤外線カメラなど民生利用にも有用である。
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