High M/L ratios of UCDs: a variation of the IMF?

Abstract

Various studies have established that the dynamical M/L ratios of ultra-compact dwarf galaxies (UCDs) tend to be at the limit or beyond the range explicable by standard stellar populations with canonical IMF. We discuss how IMF variations may account for these high M/L ratios and how observational approaches may in the future allow to discriminate between those possibilities. We also briefly discuss the possibility of dark matter in UCDs.

4 pages, 4 figures, contribution to the conference "Galactic and Stellar Dynamics in the Era of High Resolution Surveys", 16-20 March 2008, Strasbourg. Eds. C. Boily, F. Combes, G. Hensler. 2nd version includes 2 new references

References in corpus (8)

• On the self-enrichment scenario of galactic globular clusters: Constraints on the IMF
• From star clusters to dwarf galaxies: The properties of dynamically hot stellar systems
• The Nature of UCDs: Internal Dynamics from an Expanded Sample and Homogeneous Database
• Uniting Old Stellar Systems: From Globular Clusters to Giant Ellipticals
• Dynamical masses of ultra-compact dwarf galaxies in Fornax
• Bright globular clusters in NGC 5128: the missing link between young massive clusters and evolved massive objects
• The formation of ultra-compact dwarf galaxies and nucleated dwarf galaxies
• An extreme IMF as an explanation for high M/L ratios in UCDs? The CO index as a tracer of bottom heavy IMFs

Cited by in corpus (4)

• The formation of UCDs and massive GCs: Quasar-like objects for testing for a variable stellar initial mass function (IMF)
• The AIMSS Project II: Dynamical-to-Stellar Mass Ratios Across the Star Cluster - Galaxy Divide
• How elevated is the dynamical-to-stellar mass ratio of the ultra-compact dwarf S999?
• A search for active galactic nuclei in low-mass compact galaxies