On the ultra-compact dwarf galaxy-nuclear star cluster connection

Ultra-compact dwarf galaxies (UCDs) are predominatly found in the cores of nearby galaxy clusters, regions that are dominated by early-type galaxies, among them nucleated dwarf ellipticals. One of the favourite scenarios for the origin of UCDs is that they are isolated nuclei from threshed dwarf galaxies or maybe also from disrupted late-type spiral galaxies that fell into the clusters. In this scenario one would expect to find super massive black holes (SMBHs) in the centres of UCDs. Indeed, in a handful of massive UCDs SMBHs with a surprisingly high mass fraction have been detected recently. I will present the most recent results on those measurements as well as structural parameters and abundance analyses of UCDs and bright globular clusters in nearby galaxy clusters. Based on the analysis of cosmological simulations regarding the threshing scenario for UCD formation I will argue that not all UCDs can be explained by stripped nuclei.

24/05/2018 - 12:30
Dr. Michael Hilker