致密介质中柱状喷流的伽玛射线暴余辉
发布时间：2018-12-28 19:33
【摘要】：很多伽玛射线暴应当是产生于极端相对论性的喷流.关于喷流,绝大多数的讨论都是围绕锥状喷流展开.然而有观测发现,一些天体中的喷流在很长距离上始终保持着几乎不变的截面积,即表现为柱状喷流.研究致密介质环境中有侧向膨胀的柱状喷流的余辉,描述其动力学演化和辐射过程,分别得到解析解和数值解,并对两者进行了对比.研究的暴周星际介质是光学厚的,在初始的主暴阶段,喷流辐射出高度准直的高能射线,升华了暴周介质,形成一个在光学波段光学薄的柱状通道.余辉阶段,由于喷流是有侧向膨胀的,观测者只能收集到视觉面积占比例越来越小的光学辐射,理论上可得到衰减极为快速的光变曲线,流量随时间的衰减约为S_ναt~(-p-1)(p为电子幂律分布的谱指数).如此迅速的衰减使得光学余辉将难以被观测到,提供了一种对暗伽玛射线暴的解释.
[Abstract]:Many gamma-ray bursts should be caused by extremely relativistic jets. Most of the discussions on jet flow revolve around conical jets. However, some observations show that the jet flow in some celestial bodies remains almost unchanged at a long distance, that is, the jet is a columnar jet. The afterglow of a cylindrical jet with lateral expansion in a dense medium is studied, its dynamic evolution and radiation process are described, and the analytical and numerical solutions are obtained, respectively, and compared with each other. The studied interstellar medium is optically thick. In the initial main burst phase, the jet radiates highly collimated high-energy rays, sublimates the burst circumference medium, and forms a cylindrical channel with optical thin in the optical band. In the afterglow stage, due to the lateral expansion of the jet, the observer can only collect the optical radiation which accounts for a smaller and smaller proportion of the visual area. The decay of flow rate with time is about S _ v 伪 t ~ (-p ~ (-1) (p is the spectral exponent of the distribution of electron power law). Such rapid decay makes it difficult to observe optical afterglow, providing an explanation for dark gamma ray bursts.
【作者单位】： 南京大学天文与空间科学学院;
【基金】：国家自然科学基金项目(11033002) 973计划(2009CB824800)资助
【分类号】：P172.3
[Abstract]:Many gamma-ray bursts should be caused by extremely relativistic jets. Most of the discussions on jet flow revolve around conical jets. However, some observations show that the jet flow in some celestial bodies remains almost unchanged at a long distance, that is, the jet is a columnar jet. The afterglow of a cylindrical jet with lateral expansion in a dense medium is studied, its dynamic evolution and radiation process are described, and the analytical and numerical solutions are obtained, respectively, and compared with each other. The studied interstellar medium is optically thick. In the initial main burst phase, the jet radiates highly collimated high-energy rays, sublimates the burst circumference medium, and forms a cylindrical channel with optical thin in the optical band. In the afterglow stage, due to the lateral expansion of the jet, the observer can only collect the optical radiation which accounts for a smaller and smaller proportion of the visual area. The decay of flow rate with time is about S _ v 伪 t ~ (-p ~ (-1) (p is the spectral exponent of the distribution of electron power law). Such rapid decay makes it difficult to observe optical afterglow, providing an explanation for dark gamma ray bursts.
【作者单位】： 南京大学天文与空间科学学院;
【基金】：国家自然科学基金项目(11033002) 973计划(2009CB824800)资助
【分类号】：P172.3
【参考文献】
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1 黄永锋,谭长宜,戴子高,陆W，
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