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A Clash of Clusters Provides New Clue to Dark Matter
Special ACKS Seminar: Dragan Huterer
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ACKS Seminar: Rachel Somerville (MPIA Heidelberg)
| What | seminar ACKS |
|---|---|
| When |
18 January 07 from 04:00 pm to 05:30 pm |
| Where | SLAC: FKB 3rd Fl. Conf. Rm. |
| Contact Name | Risa Wechsler |
| Contact Email | rwechsler@stanford.edu |
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The assembly of galaxies and their black holes: the role of AGN feedback in galaxy formation
Abstract
One of the most profound discoveries in modern astronomy is that most galaxies host supermassive black holes (SMBH), and that the properties of the SMBH and their hosts seem to be intimately connected. Even more intriguing is that the activity we witness via accretion onto SMBH (quasars and Active Galactic Nuclei; AGN) and the observed star formation activity both seem to rise and fall over cosmic history in almost perfect synchronization. Moreover, both star-forming galaxies and AGN show the same "downsizing" trend: the activity drops earlier and more rapidly in more massive objects. A new theoretical picture has emerged in which galaxies and their black holes grow in tandem, and black holes are responsible for regulating star formation and thus shaping many of the basic relationships between galaxy properties. In this picture, AGN feedback is invoked to solve a host of long-standing problems suffered by Cold Dark Matter (CDM) models of galaxy formation. For example, it has been suggested that AGN feedback could shut down cooling flows and quench star formation in massive galaxies, producing the observed bimodality in galaxy colors, morphologies, and star formation histories. I will discuss two different proposed mechanisms by which the energy released by accreting black holes can couple to the gas that fuels forming galaxies, and how these processes might affect observable properties of galaxies at low and high redshift.
MASS: Lance Simms