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Science. 2014 Sep 12;345(6202):1330-3. doi: 10.1126/science.1251053. Epub 2014 Aug 7.

Rapid growth of seed black holes in the early universe by supra-exponential accretion.

Author information

1
Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel. tal.alexander@weizmann.ac.il.
2
Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511, USA.

Abstract

Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time t(E) ~ few × 0.01 billion years is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 billion years old. We propose a dynamical mechanism that can trigger supra-exponential accretion in the early universe, when a BH seed is bound in a star cluster fed by the ubiquitous dense cold gas flows. The high gas opacity traps the accretion radiation, while the low-mass BH's random motions suppress the formation of a slowly draining accretion disk. Supra-exponential growth can thus explain the puzzling emergence of supermassive BHs that power luminous quasars so soon after the Big Bang.

PMID:
25103410
DOI:
10.1126/science.1251053
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