26 March 2009

Speaker: Marianne Vestergaard (Tufts University)

Title:Accreting Supermassive Black Holes Across Cosmic History

Abstract:Black holes are no longer simply a mathematical curiosity. They are ubiquitous and inhabit the centers of most, if not all, galaxies. They are powerful tools for studying particle acceleration, strong gravity fields, and accretion properties of stellar and galactic sources. Supermassive black holes appear crucial to our understanding of the formation and evolution of mass structures across cosmic time. For example, actively accreting supermassive black holes hold the promise of explaining the properties and evolution of the red, non-starforming galaxy population as well as one of the heating mechanisms of the intracluster gas in galaxy clusters which has important implications for the properties of the member galaxies. To fully understand the detailed cosmological role of black holes we need to also understand the demographics of supermassive black holes as well as how they form and grow across cosmic time. In this talk, I will give an overview of mass determinations of activ ely accreting black holes, the potential systematics involved, and our efforts to understand these. I will describe the results obtained when applying these mass estimation techniques to large surveys of quasars, including the Sloan Digital Sky Survey, which covers a large range of cosmic history. Specifically, we are in the process of determining the mass functions of accreting supermassive black holes at a range of look-back time and I will discuss some of our current results.

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