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。研究了宇宙射线加速的位置和机制。分析估计，磁场方向和冲击正常不平行的倾斜冲击的最大能量是可实现的。对于超新星残留和射电星系而言，它分别为10^<16>和10^<20> eV，这可能解决了长期存在的问题。此外，我进行了蒙特卡洛模拟，证实了分析估计。对加速过程的几何影响正在研究中。2。我研究了可以在观察上证实加速理论的可能性。由于预计加速位点的宇宙射线光谱比在地球上观察到的频谱要比观察到的要平坦得多，因此在加速位点发射的伽马射线光谱也应平坦。我计算了预期的超新星残留物的伽马射线通量，发现通量刚好低于现有仪器的检测极限，并且可以通过正在建造的Cerenkov望远镜和EAS阵列可观察到。3。我还研究了Blazars的GEV伽马射线排放，这些发射最近是由Egret在CGRO卫星上发现的。我认为，伽马射线是由相对论电子在光束射流中从软光子中散射的反向射线产生的。我将冲击加速度理论应用于这个问题。我发现，由于辐射冷却，应出现电子光谱的断裂，并且该断裂对应于3C279约10mev的光子能量。