Rapid growth of seed black holes in the early universe by supra-exponential accretion
| Autor: | Alexander, Tal, Natarajan, Priyamvada |
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| Rok vydání: | 2014 |
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| Zdroj: | Science, 12 September 2014, Vol. 345 no. 6202 pp. 1330-1333 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1126/science.1251053 |
| Popis: | 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 x 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 trapped 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. Comment: Some typos corrected and minor stylistic changes to conform with final printed version. 18 pages (main article and supplementary materials) and 3 figures. First appeared in Science Express: http://www.sciencemag.org/content/early/2014/08/06/science.1251053. Final printed version: T. Alexander, P. Natarajan, Science, 12 September 2014, Vol. 345 no. 6202 pp. 1330-1333 |
| Databáze: | arXiv |
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