From accelerated particles to cosmic rays --- Understanding particle acceleration and escape with New-generation X-ray/gamma-ray observatories

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K05107
• 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: The University of Tokyo (2016-2018); Aoyama Gakuin University (2015)
• Principal Investigator: Bamba Aya 東京大学, 大学院理学系研究科(理学部), 准教授 (70392082)
• Research Collaborator: Yamazaki Ryo ; Yamaguchi Hiroya
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 宇宙線 / 超新星残骸 / プラズマ / X線宇宙物理学

Outline of Final Research Achievements

Cosmic rays are one of the elemental components of our Galaxy, but the origin is still unclear. Shocks of supernova remnants are the prime candidate of efficient acceleration. The remaining problem is understanding how particles can escape to be cosmic rays. We used the time scale of rapid-cooling plasma due to the interaction with molecular clouds as a clock from particle escape due to the interaction and dumping of magnetic field. We found with X-ray (plasma) and gamma-ray (accelerated protons) observations that higher energy particles escape more rapidly compared with lower energy particles.

Free Research Field

X線宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

宇宙線は宇宙マイクロ波背景放射や星光と同程度のエネルギー密度を持つ、我々の銀河の基本構成要素の一つであり、地上でも自然放射線の3割を占める。また、最高エネルギーは10^20電子ボルトにもなり、地上の実験加速器では到底再現できない素粒子物理学の探求も可能である。宇宙線の起源の理解の最後の1ピースのひとつであった、加速粒子が加速現場から逃亡し宇宙線になる瞬間をとらえた意義は大きい。