THEORETICAL STUDY OF COSMIC RAY ASTROPHYSICS

宇宙射线天体物理学的理论研究

基本信息

批准号：
04640307
负责人：
TAKAHARA Fumio
金额：
$ 1.34万
依托单位：
TOKYO METROPOLITAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04640307/
关键词：
Particle Acceleration Origin Of Cosmic Rays Shock Waves Supenova Remnants Gamma-Ray Astronomy Active Galactic Nuclei Relativistic Jets 軽元素の起源

项目摘要

1. The site and mechanism of cosmic ray acceleration are studied. The attainable maximum energy for oblique shocks, where the magnetic field direction and the shock normal is not parallel, is estimated analytically. It turns out to be 10^<16> and 10^<20>eV for supernova remnants and radio galaxies, respectively, which possibly resoved the long standing problem. Further, I have made Monte Carlo simulations, which confirmed the analytic estimates. Geometrical effects on the acceleration process is under investigation.2. I studied a possibility to observationally confirm the acceleration theory. Since the cosmic ray spectrum at the acceleration site is expected to be much flatter than that observed on the earth, the gamma-ray spectrum emitted at the acceleration site should also be flat. I calculated expected gamma-ray flux from supernova remnants, and found that the flux is just below the detection limit of existing instruments and can be observable by Cerenkov telescopes and EAS arrays under construction.3. I also studied GeV gamma-ray emission from blazars which have recently been discovered by EGRET on board CGRO satellite. I argued that gamma-rays are produced by the inverse Compton scattering off soft photons by relativistic electrons in a beamed jet. I applied shock acceleration theory to this problem ; I found that a break in the electron spectrum should appear due to radiative cooling and that this break corresponds to the photon energy of around 10MeV for 3C279.

1、研究宇宙线加速的场所和机制。通过分析估计磁场方向和冲击法线不平行的倾斜冲击可达到的最大能量。超新星遗迹和射电星系的值分别为 10^<16> 和 10^<20>eV，这可能解决了长期存在的问题。此外，我还进行了蒙特卡罗模拟，证实了分析估计。加速过程的几何效应正在研究中。2．我研究了通过观察证实加速理论的可能性。由于加速地点的宇宙射线光谱预计比在地球上观测到的要平坦得多，因此加速地点发射的伽马射线光谱也应该是平坦的。我计算了超新星遗迹的预期伽马射线通量，发现该通量略低于现有仪器的探测极限，可以通过切伦科夫望远镜和正在建设的EAS阵列观测到。3．我还研究了最近由 CGRO 卫星上的 EGRET 发现的耀变体发出的 GeV 伽马射线。我认为伽马射线是由射流中的相对论电子对软光子进行逆康普顿散射而产生的。我应用冲击加速度理论来解决这个问题；我发现由于辐射冷却，电子光谱中应该会出现中断，并且该中断对应于 3C279 约 10MeV 的光子能量。