报告题目：Origin of Ultra-compact Dwarfs in the Virgo Cluster

　　报 告 人：张红欣（北京大学科维理天文与天体物理研究所） 　　摘    要：The origin of ultra-compact dwarfs (UCDs) -- objects larger and more massive than typical globular clusters (GCs), but more compact than typical dwarf galaxies -- has been hotly debated in the fifteen years since their discovery.It is not clear whether most UCDs should be considered galactic in origin, or simply the most extreme GCs. I will present the first ever detailed study of the global dynamical propertes of nearly 100 confirmed UCDs associated with the central cD galaxy M87 toward the Virgo core region. In this talk, the similarities and differences between UCDs, GCs, and present-day dwarf galaxies will be presented, and the implication about the origin of UCDs will be discussed. At the end, I will briefly motivate our ongoing work on studies of stellar populations and internal dynamics of Virgo UCDs.

　　时    间：2015年1月8日（星期四）上午11：00

　　地    点：紫台5楼小会议室

　　联 系 人：马红君（83332210）

欢迎大家积极参加！

　                                         　紫金山天文台学术委员会