近期十分令人关注的伽玛射线暴事件

活动时间： 01月29日14时30分       

地            点  ： 理科群2号楼C320

讲座内容：

In the talk I will review our recent workon the most remarkable Gamma-Ray Bursts (GRBs) in last two years: GRB 160625Band GRB 170817A. GRB 160625B is an extraordinarily bright burst with threeisolated episodes separated by long quiescent intervals. By conducting detailedtime-resolved spectral analysis in each episode, we found the spectral propertiesof the first two sub-bursts are distinctly different, allowing us to for thefirst time observe a clear transition from thermal to non-thermal radiationbetween well-separated emission episodes within a single GRB. Such a transitionis a strong indication of the change of jet composition from a fireball to aPoynting-flux-dominated jet. GRB 170817A is the first confirmed short GRBassociated with gravitational event GW170817. By performing detailed analysison the prompt emission data, we show that the fluence and spectral peak energyof this sGRB fall into the lower portion of the distributions of known sGRBs.Its peak isotropic luminosity is abnormally low. The estimated event rate densityabove this luminosity is at least   ~190 Gpc^-3yr^-1, which is close to butstill below the DNS merger event rate density. The physical implicationsincluding the jet structure will also be discussed.

主讲人介绍：

张彬彬，南京大学天文与空间科学学院副教授，博士生导师。2003年河北师范大学物理学院本科毕业，2011年美国内华达大学博士毕业，2011年至2017年在美国宾夕法尼亚州立大学、美国阿拉巴马大学、西班牙安达卢西亚天体物理研究所从事科研工作, 期间同时在NASA的科学卫星Swift和Fermi科学组中从事伽玛暴的数据分析和理论研究，2017年获得国家青年千人计划资助并加入南京大学伽玛暴研究团队。目前已在Science、Nature Astronomy、 ApJ、 ApJL、 Physical Review D、MNRAS 等杂志上发表SCI论文共80余篇，总引用超过3600次。

发布时间：2018-01-28 09:03:09