新疆天文台学术报告2019年第09次

报告题目：吸积白矮星的X射线铁发射线与白矮星质量研究

报 告 人：徐晓杰 博士 南京大学

报告摘要:

The flux ratio of Fe XXVI–Lyα to Fe XXV–Heα lines (I7.0/I6.7) is a sensitive indicator of the maximum temperature (Tmax), and therefore the mass of white dwarf stars (MWD) in cataclysmic variables (CVs). To examine and calibrate the theoretical I7.0/I6.7–Tmax–MWD relations, reliable measurements of Tmax and I7.0/I6.7 are necessary. In this work, we conduct a thorough investigation of 3–50 keV X-ray spectra of 25 solar neighborhood magnetic and nonmagnetic CVs based on archival NuSTAR and Suzaku observations. The measured Tmax are compared to the I7.0/I6.7 and MWD. The results show that the sampled CVs closely follow the theoretical I7.0/I6.7–Tmax relation. Moreover, all the MWDestimated from I7.0/I6.7 are consistent with the dynamically measured ones. We conclude that I7.0/I6.7 can be used as a good diagnostic for Tmax and MWD in both magnetic and nonmagnetic CVs.  We further apply the relations to the CVs in the Galactic center (GC) and in the Solar vicinity, and measure the WD masses in those CVs. The results show that WDs in GC CVs are more massive than those in the Solar vicinity, which could be due to the dynamical encounters in the GC region.

报告人简介：

徐晓杰博士于2006年在南京大学天文学系本科毕业，2006-2012年在南京大学天文学系跟随李向东教授读研究生（其中2010.9-2012.9赴美国麻省大学天文学系王青德教授处合作培养），并于2012年获得理学博士学位。此后在南京大学工作至今，分别任助理研究员和副研究员。其主要研究方向为：吸积白矮星的X射线辐射、激变变星的星族性质的观测与模拟等。

报告时间：2019年07月18日（周四）上午11:00

报告地点：台本部南楼210会议室