Study of origins and propagation of very high energy cosmic rays with detailed measurements in the wide energy range

2023 Fiscal Year Final Research Report

• Project/Area Number: 19H05607
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Review Section: Broad Section B
• Research Institution: The University of Tokyo (2020-2023); Osaka City University (2019)
• Principal Investigator: Ogio Shoichi 東京大学, 宇宙線研究所, 教授 (20242258)
• Co-Investigator(Kenkyū-buntansha): 竹田 成宏 東京大学, 宇宙線研究所, 助教 (40360581) ; 常定 芳基 大阪公立大学, 大学院理学研究科, 教授 (50401526) ; 有働 慈治 神奈川大学, 工学部, 准教授 (50506714) ; 冨田 孝幸 信州大学, 学術研究院工学系, 助教 (70632975) ; 多米田 裕一郎 大阪電気通信大学, 工学部, 准教授 (90467019)
• Project Period (FY): 2019-06-26 – 2024-03-31
• Keywords: 銀河系内宇宙線 / 銀河系外宇宙線 / 原子核組成

Outline of Final Research Achievements

The Telescope Array Experiment (TA), an international joint experiment involving about 150 researchers from nine countries and regions including Japan, the United States, and South Korea, has been operating the largest cosmic ray observatory in the Northern Hemisphere in Utah, USA, since 2008. Through this research, the TA experiment has succeeded in lowering the cosmic ray detection energy to the 10　to the15th power electron volt (eV) region, and is continuing stable observations. In addition, the cosmic-ray energy spectrum and chemical composition (three-component composition ratios of representative nuclear species, hydrogen, nitrogen, and iron, and their energy variations) in the region from 10 to the17th to 10 to the19th power eV, where galactic- and extragalactic cosmic rays are coexisting, were obtained observationally.

Free Research Field

宇宙線物理学

Academic Significance and Societal Importance of the Research Achievements

本研究によって集められた観測データは今後速やかに解析されて、10の15乗 eV以上での銀河系内成分スペクトル、系内成分の化学組成とそのエネルギー依存性、銀河系外成分スペクトル、化学組成などが明らかになる。これらの観測的成果は１）銀河系外宇宙線源天体とその進化の解明、（２）銀河間磁場の強さと構造に対する示唆、（３）宇宙線の遮蔽・閉じ込めの解明から、宇宙線・銀河磁場・銀河ハローを含めた多体系としての銀河系の物理、（４）銀河系内宇宙線源天体の解明、（５）粒子加速理論の構築、に寄与する。