伽玛射线暴及其余辉研究进展

Progresses in the Researches of Gamma-Ray Bursts and their Afterglows

伽玛射线暴是一种来自宇宙空间随机方向的短时间内伽玛射线突然增亮的现象。伽玛射线暴虽然早在1967年就由Vela卫星观测到,但直到1997年人们才通过余辉观测确定其寄主星系,并通过寄主星系的红移最终确定了伽玛射线暴的宇宙学起源。对伽玛射线暴研究概况进行了评述:详细介绍了伽玛射线暴及其余辉的观测进展,特别是近期Swift卫星和Fermi卫星带来的新发现;系统描述了伽玛射线暴标准火球模型、伽玛射线暴余辉物理(相对论性外流与暴周环境介质的相互作用过程、辐射产生机制等)及伽玛射线暴的前身星等。也对伽玛射线暴的未来研究进行了展望。

GammaRay Bursts （GRBs） served from the sky in random directions are short and intense flashes of gamma-rays obAlthough discovered as early as in 1967 by Vela satellite, GRBs were confirmed to be of cosmological origin through the observation of their afterglows and host galaxies till 1997. In this article, the recent progresses in observations and theories, especially in the Swift and Fermi eras, are briefly reviewed. The standard fireball model is described first. A detailed description on the origin of afterglows, i.e., synchrotron radiation of relativistic electrons which are accelerated by the shocks from the interaction between the relativistic outflows and surrounding medium, is then presented. The micro physics of shocks and the nonthermal radiation mechanisms is also addressed in detail. In Section 3, the progenitors of different kinds of GRBs are introduced. Finally, a short prospect is given.