5 April 2007

Speaker: Beth Willman (CfA)

Title:Clay Lecture:
The Stellar Halos of Galaxies

Abstract: Halos of stars around disk galaxies are a natural consequence of hierarchical galaxy formation. Galaxy stellar halos are predicted to be systems built from merging proto-galaxies, and their properties are a strong function of galaxy formation history. As such, stellar halos are widely considered to contain fossil records of the process of galaxy formation. However, interpreting their observed properties in a cosmological context has been daunting: Not only are stellar halos difficult to observe owing to their low surface brightness, but they have historically been difficult to model. I will present new results from cutting-edge numerical simulations of galaxy formation to investigate the origin and observable properties of the stellar halos around disk galaxies in a Cold Dark Matter Universe. Based on these results, I will interpret some observations of stellar halos in the nearby Universe that have recently posed a challenge to the hierarchical model of galaxy formation.

Video of the Presentation (Talks can be viewed with RealPlayer. Free download is available from www.real.com )