In the talk I will review our recent work on Gamma-ray Bursts (GRBs) in last two years. (i) We study the afterglow by analysing the temporal evolution of color indices (CI), defined as the magnitude difference between two filters. We find that a majority of the CI do not vary with time, which means that the spectral slope does not change, even between different emission episodes. For the other cases, the variation is found to occur during limited periods. We suggest that they are due to the cooling frequency passing over the observed filter bands and, in other cases, due to the emergence of the underlying supernova emission. (ii) We study the energetics of the GRBs that can be inferred from the afterglow observations. Using this information we analyse the limits it sets on what the central engine can be, if it is a magnetar or a spinning blackhole. Assuming that the magnetar energy is emitted isotropically, we find that most bursts are consistent with a BH central engine and only around 20% are consistent with a magnetar central engine.
Interpretation of gamma-ray burst X-ray and optical afterglow emission – From the central engine to the circumburst interaction
主讲人单位 (Speaker's Institute):
邀请人 (Invited by):
星期四, 2018/06/28 - 10:30 to 11:30
珠海校区海滨红楼17栋107 (Rm 107, Red House 17)
主讲人简介 (Speaker's CV):
李亮，2009年6月四川师范大学物理学院物理学专业本科毕业，2018年2月获得瑞典斯德哥尔摩大学和法国尼斯大学天体物理学专业双博士学位，博士期间获得欧盟著名的伊拉斯谟博士奖学金的资助。2018年3月至今在波兰克拉克夫天文台和意大利佩斯卡拉ICRANet实验室从事科研工作，期间同时在NASA的科学卫星Fermi和Swift科学组从事伽玛暴的数据分析和理论研究。主要从事高能天体物理的研究，包括伽玛暴，超新星等。目前在Science, Physical Review Letters, ApJS, ApJ, A&A, Physical Review D等国际一流杂志上发表SCI论文共30余篇。