Flow Geometry Variation of IGR 17091-3624 as revealed by Comptonizing Efficiency and a Comparison with GRS 1915+105

主讲人 (Speaker): 
Partha Sarathi Pal
主讲人单位 (Speaker's Institute): 
Indian Centre For Space Physics, Kolkata
邀请人 (Invited by): 
时间 (Time): 
星期三, 2017/06/21 - 11:00 to 12:00
地点 (Location): 
珠海校区海滨红楼17栋107 (Rm 107, Red House 17)
摘要 (Abstract): 

Variability class transitions in the enigmatic black hole candidate GRS 1915+105 have been known to accompany variation of distinct flow geometry as is evidenced by the behavior of Comptonizing Efficiency (CE) defined to be the ratio between the number of powerlaw photons and injected seed photons. Similarities of the variability class transitions between GRS 1915+105 and IGR 17091-3624 have been reported in the literature.  We examine CE of IGR 17091-3624 and find that it is also similar in these two objects, particularly when the variability classes are similar even though their masses are believed to be widely different. This shows that characterization of variability classes based on dynamical hardness ratios which the CEs represent (and not based on normal hardness ratios or color-color plots) is likely to be black hole mass independent.

主讲人简介 (Speaker's CV): 
Partha Sarathi Pal为我校拟聘任博士后研究员,一直从事河内X射线双星与黑洞相关的天体物理研究,研究手段包括利用各种空间X射线望远镜对特定的几个源,如IGR 170913624和GRS 1915+105等,进行深入的数据分析。