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The Ohio State University
College of Mathematical & Physical Sciences
Department of Astronomy Colloquium Series 2006/7
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Thursday, March 8, 3:30 p.m.
2015 McPherson Laboratory
The First Supermassive Black Holes?
Mitchell Begelman
JILA, University of Colorado
The existence of a supermassive black hole in nearly every galactic
nucleus is no longer in doubt, but the question of how these black holes
formed is wide open. I will argue that they could have formed via the
direct infall and collapse of gas in pregalactic haloes at redshifts
10 - 20, without the intermediate stage of Pop III star formation.
Global gravitational instabilities get rid of excess angular momentum,
and the infalling gas forms a self-gravitating, optically thick
structure: a "quasistar". As matter piles on, the core of the
quasistar heats up until it undergoes runaway neutrino cooling and
collapses to form a 10 solar mass black hole. The black hole then
grows by accreting from the quasistar at an extremely super-Eddington
rate, reaching thousands of solar masses in less than a million years.
Concurrently, the quasistar expands to form a radiation pressure-dominated,
convective envelope reminiscent of a red giant. I will discuss
the structure and evolution of quasistars and their detectability
with the James Webb Space Telescope.
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