SHAO Astrophysics Colloquium

Title: Ultra-compact dwarf galaxies (UCDs) in the Virgo cluster

Speaker: Chengze Liu (Shanghai Jiao Tong University)

Time: 3:00 pm, January 09 (Thursday)

Location: Lecture Hall, 3rd floor

Abstract: 

For many decades, it was widely believed that galaxies and star clusters were completely distinct populations. However, in the late 1990s, a new type of compact stellar system, Ultra-Compact Dwarf (UCD) galaxies, was discovered to have some properties that bridged the gap between compact, dwarf galaxies and globular clusters. Roughly 20 years after their discovery, the origin of UCDs remains surprisingly obscure. In this talk, I will present results for UCDs in the Virgo cluster based on imaging mainly from the Next Generation Virgo Cluster Survey (NGVS). We have identified more than 600 candidate UCDs from the cluster core to the virial radius. This is the largest and most homogeneous sample of UCDs presented to date for any cluster environment, and the first of its kind for the Virgo cluster. I will summarize the basic statistical properties of the UCD sample, compare to the GCs and nuclei, identify any special UCDs we found and give the observational constrains on the origin of UCDs.