摘要：Ultraluminous X-ray sources (ULXs) are off-nucleus X-ray sources discovered in the Milky Way and nearby galaxies which have isotropic X-ray luminosity exceeding the Eddington luminosity of typical stellar-mass black holes. ULXs are ideal laboratory to study the super-Eddington accretion by stellar-mass black holes and neutron stars, as well as the intermediate-mass black holes. The optical observations have been a key approach to investigate the nature of the compact primary and their accretion states. Dynamical modeling based on optical spectroscopy may constrain the mass, and thus physical nature, of the compact object. Multi-band optical imaging can reveal the stellar environments of ULXs. Furthermore, extended ionized nebulae have been discovered around ULXs, which may be used to derive the kinematics of ULX outflows. In this talk, I will first review the optical studies of ULXs. Then I will present a case study of the ULXs in the Whale Galaxy NGC 4631.

简介：武剑锋，厦门大学天文学系教授、博士生导师。本科和硕士毕业于清华大学物理系，博士毕业于宾夕法尼亚州立大学天文与天体物理系，其后在哈佛-史密松天体物理中心与密歇根大学进行博士后研究。2017年入选国家海外高层次青年人才计划。研究领域为黑洞天体物理学，以各种质量尺度的黑洞为对象，研究黑洞周围的基本物理学规律和宇宙的演化历史。中国“慧眼”硬X射线调制望远镜、中国空间站巡天望远镜、“爱因斯坦探针”X射线望远镜科学工作组成员。教学方面，曾获得厦门大学英语教学比赛一等奖（理工医组第一名）。其主讲的《黑洞与引力波》课程入选厦门大学一流本科课程，并受邀成为首批厦门大学美育与通识教育一流课程。