伽玛暴的高能余辉及其辐射效率理论物理专业论文.docxVIP

我,frith道伽玛暴爆发周围介质情况对于计算火球动能是有影响的。所 我,frith道伽玛暴爆发周围介质情况对于计算火球动能是有影响的。所 以，在本论文的第三章，我们就分别详细地讨论了不同的暴周环境对伽玛 暴辐射效率的影响。主要分以下两种情况：均匀星际介质情况和星风情 况。 关键词：伽玛射线暴高能辐射余辉辐射效率 Ⅳ 万方数据 HIGH HIGH ENERGY AFTERGLOW AND RADIATIVE EFFICIENCY 0F GAMMA—RAY BURST ABSTRACT Gamma—ray bursts(GRBs)are transient events produced in the universe， which is increasing suddenly in short time and weakening fast．While they are on，they outshine the whole galaxy．It is one of the most active research fields in astrophysics．We first present a review of gamma—ray bursts in both observations and theories，including the significant observation progress in history，the light curves and spectra，the broadband afterglow emission，the fireball model，the observation features of high energy emission，the high energy emission processes in the GRBs and afterglows，the Fermi satellite introduction，which is related to my research． In Chapter 2，we present detailedly my postgraduate work_bi曲energy afterglow and radiative efficiency of gamma—ray burst．High energy afterglow is gamma—ray emission which is above 1 00 MeV after prompt emission．The GRB radiative efficiency is an essential quantity to understand the nature of the bursts． It gives a direct measure of how efficient the burst dissipates the total energy into radiation during the GRB prompt emission phase．So far，the widely accepted model of GRB is the fireball model．According to fireball model，GRB radiative efficiency is very small．However，the X—ray afterglow observation show that the efficiency is high．So the observation data pose a challenge to the fireball model．We present 8 bright GRBs(fluence3 105erg cm。2 during prompt emission phase of gamma—ray bursts)which are codetected by the V 万方数据 GBM GBM and the LAT onboard the Fermi satellite，give a systematic analysis of the prompt emission，estimate their isotropic energy in the 8 keY一1 00 GeV band． We use the standard afterglow model，make several simplifying assumptions including using a single typical value for t=0．1，岛=0