17 February 2005

Speaker: Marta Volonteri (Institute of Astronomy, Cambridge, UK)

Title: Hierarchical Assembly of Massive Black Holes

Abstract: Several lines of evidence support the idea of a co-evolution of galaxies, quasars and black holes. The observation of quiescent supermassive black holes (SMBHs) in nearby normal galactic centers suggests a link with an earlier quasar epoch, with local SMBHs representing the remnants of the once active sources. Also, a very early assembly epoch is suggested by the discovery of luminous quasars around redshift z~6. In this talk I will discuss a scenario for the hierarchical evolution of a SMBHs population. The seeds of the local SMBHs are assumed to be 'pregalactic' black holes, remnants of the first POPIII stars. As these pregalactic holes become incorporated through a series of mergers into larger and larger halos, they sink to the center owing to dynamical friction, accrete a fraction of the gas in the merger remnant to become supermassive, form a binary system, and eventually coalesce. The consequences of black hole mergers and of mass growth via gas accretion will be critically addressed.

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

References for students:

1. Volonteri, Haardt and Madau 2003, ApJ, 582, 559
2. Volonteri, Madau, Quaetert and Rees 2004 (astro-ph/0410342)
3. Merritt et al. 2004, ApJL, 607, 9