Program: GS-2008B-Q-6

Ultra-compact dwarf galaxies (UCDs) are very compact stellar systems discovered in the Virgo and Fornax Clusters. We are trying to understand the origin of these objects. Our recent AAT and Gemini observations suggest-surprisingly-that the populations of UCDs differ in the two clusters. The evidence for this is based on the numbers of UCDs and their colours. We propose to use Gemini-S/GMOS spectroscopy to measure the ages, metallicities and abundances for a sample of Fornax UCDs. We will compare these with our existing Gemini measurements of Virgo UCDs to test our hypothesis that both clusters contain UCDs like globular clusters, but the Fornax Cluster also contains an additional population of more luminous metal-rich objects formed by the disruption of dwarf galaxies.