Study of Gamma-Ray Bursts with Imaging Atmospheric Cherenkov Telescopes

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K20368
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0203:Particle-, nuclear-, astro-physics, and related fields
• Research Institution: Hiroshima University
• Principal Investigator: Suda Yusuke 広島大学, 先進理工系科学研究科(理), 助教 (70910321)
• Project Period (FY): 2021-08-30 – 2024-03-31
• Keywords: ガンマ線バースト / 残光 / シンクロトロン自己コンプトン放射 / 超高エネルギーガンマ線 / 大気チェレンコフ望遠鏡 / MAGIC / CTA / LST

Outline of Final Research Achievements

We have studied gamma-ray bursts (GRBs) observed by the MAGIC telescopes. A dedicated low-energy analysis was performed on the GRB 201216C data observed by MAGIC. We found that the observed multi-wavelength data, including sub-TeV data, can be naturally explained by a synchrotron self-Compton emission mechanism, and we published a paper on this finding. The MAGIC data analysis of GRB 201015A, in which MAGIC observed a hint of gamma-ray emission, was completed, and a paper is in preparation. To further improve sensitivity, we established an analysis pipeline for joint observations with MAGIC and the Large-Sized Telescope prototype (LST-1) for the Cherenkov Telescope Array Observatory. It was found that the joint observations have the capability to detect sources that are 30% (40%) weaker compared to MAGIC (LST-1) mono observations. We published a paper reporting the performance of the joint observations.

Free Research Field

ガンマ線天文学

Academic Significance and Societal Importance of the Research Achievements

ガンマ線バーストの研究は2019年のMAGICによるTeVガンマ線放射の発見により新たな局面を迎えたが、TeV帯域でガンマ線バーストの検出に成功した例は数例しかないため、その放射機構については未解明な点が多い。そのため本成果により新たなサンプルが加えられた意義は大きい。また、低エネルギー側に強いMAGICの性能を活かしたGRB 201216Cの検出成功は、その後継ともいえるLSTのGRB観測に大いに期待できる成果である。MAGICとLST-1の同時解析の確立は、これを用いた今後の高感度観測はもちろん、CTA時代における複眼観測に向けたパスファインダーの役割を果たす上で重要な成果である。