Nonrelativistic phase in γ-ray burst afterglows  

作　　者：Huang Yongfeng Lu Tan Cheng Kwongsang 

机构地区：[1]Department of Astronomy, Nanjing University, Nanjing 210093, China [2]Purple Mountain Observatory, Nanjing 210008, China [3]Department of Physics, the University of Hong Kong, Hong Kong, China

出　　处：《Progress in Natural Science:Materials International》2007年第11期1261-1270,共10页自然科学进展·国际材料（英文版）

基　　金：Supported by National Natural Science Foundation of China (Grant Nos 10625313 ,10221001 ,10473023) ;the RGC grant of the Hong Kong Government under HKU7014/04P

摘　　要：The discovery of multiband afterglows definitely shows that most γ-ray bursts are of cosmological origin. γ-ray bursts are found to be one of the most violent explosive phenomena in the Universe, in which astonishing ultra-relativistic motions are involved. In this article, the multiband observational characteristics of γ-ray bursts and their afterglows are briefly reviewed. The standard model of γ-ray bursts, i.e. the fireball model, is described. Emphasis is then put on the importance of the nonrelativistic phase of afterglows. The concept of deep Newtonian phase is elaborated. A generic dynamical model applicable in both the relativistic and nonrelativistic phases is introduced. Based on these elaborations, the overall afterglow behaviors, from the very early stages to the very late stages, can be conveniently calculated.The discovery of multiband afterglows definitely shows that most γ-ray bursts are of cosmological origin. γ-ray bursts are found to be one of the most violent explosive phenomena in the Universe, in which astonishing ultra-relativistic motions are involved. In this article, the multiband observational characteristics of γ-ray bursts and their afterglows are briefly reviewed. The standard model of γ-ray bursts, i.e. the fireball model, is described. Emphasis is then put on the importance of the nonrelativistic phase of afterglows. The concept of deep Newtonian phase is elaborated. A generic dynamical model applicable in both the relativistic and nonrelativistic phases is introduced. Based on these elaborations, the overall afterglow behaviors, from the very early stages to the very late stages, can be conveniently calculated.

关 键 词：gamma-ray bursts AFTERGLOWS jets shock waves relativity. 

分 类 号：TN91[电子电信—通信与信息系统]