报告题目：Supersoft Ultraluminous X-ray Sources

　　报告人：冯骅 教授 （清华大学）

　　报告人简介：冯骅，清华大学教授。2004年获清华大学天体物理博士学位；2005-2008年在美国University of Iowa物理与天文系开展博士后研究；2008年起任教于清华大学工程物理系与天体物理中心。

　　Hua Feng's main interest is understanding the physics around accreting black holes and other high energy astrophysical objects. He conducts research in high energy astrophysics, focusing on observational X-ray astronomy and instrumentation for future space astronomy. His recent research activity involves the development of new techniques and detectors for high-sensitivity X-ray polarimetry. He leads a group in the Department of Engineering Physics devoted to the development of the photoelectric X-ray polarimeter using micropattern gaseous detectors and a soft Bragg polarimeter using multilayer mirrors. He is also interested in X-ray and optical observations of accreting black holes, trying to identify a new population of black holes with masses intermediate between the stellar-mass and supermassive black holes, or reveal observational signatures associated with super-Eddington accretion.

　　摘要：Ultraluminous X-ray sources (ULXs) are non-nuclear accreting compact objects found in external galaxies. They appear to be more luminous than Galactic black hole binaries under the assumption of isotropic emission. Evidence for intermediate mass black holes were found, but the majority of them may have supercritical accretion upon X-ray and multiwavelength  observations. I will give an overview of ULXs and then focus on a sub-class of them whose X-ray spectra are dominated by very soft thermal emission. These supersoft ULXs show similar spectral and temporal behaviors and may define a new emission state with an even higher accretion rate compared with classical ULXs.

　　时间：3月31日（周五）上午10点

　　地点：天文楼212报告厅

欢迎各位老师、同学参加！

　　                                      南京大学天文与空间科学学院