Study of the Galactic MeV cosmic rays with X-ray precision spectroscopy

2019 Fiscal Year Final Research Report

• Project/Area Number: 15H02090
• 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: Kyoto University
• Principal Investigator: Tsuru Takeshi 京都大学, 理学研究科, 教授 (10243007)
• Co-Investigator(Kenkyū-buntansha): 信川 正順 奈良教育大学, 理科教育講座, 准教授 (00612582) ; 武田 彩希 宮崎大学, 工学部, 助教 (40736667)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: X線天文学 / MeV宇宙線 / すざく衛星 / ひとみ衛星

Outline of Final Research Achievements

The Fermi satellite and air Cherenkov telescopes have provided information on the GeV and TeV cosmic-ray protons. On the other hand, there are still no observational data on MeV cosmic-ray protons, except for those in the vicinity of the Earth. We made pioneer studies of MeV galactic cosmic-ray protons by using the precise X-ray spectroscopy. The results obtained from this study are as follows. Detection of Fe-neutral 6.4 keV emission lines generated by MeV cosmic-rays at the molecular clouds in the Galactic center region and the ones at the vicinities of several supernova remnants. Modeling of emission line structures derived from multiple ionizations of neutral atoms by cosmic-ray heavy ions. Calibration of the X-ray CCD camera onboard the Hitomi satellite. Development of X-ray CCD for the XRISM satellite. Production of prototype of a new type of X-ray sensors for the Next Generation Broadband X-ray Satellite.

Free Research Field

宇宙物理学実験

Academic Significance and Societal Importance of the Research Achievements

本研究でMeV 銀河宇宙線をX線バンドから観測可能であることを示したことに大きな意義がある．「ひとみ」衛星の損失で本研究期間内での実現はできなかったものの，X線精密撮像分光が MeV 銀河宇宙線の研究分野を大きく切り拓くことを確信することができた．これはMeV 銀河宇宙線の研究の始まりに過ぎない.ここで得られるデータや知見を元に，日本も参加表明している大型のATHENA衛星や独自の広帯域X線衛星など，将来のX線ミッションにおけるサイエンスの大きな柱に成長するであろう．