Alexander 2014 宇宙早期黑洞质量快速增长的模型

主要内容:
在密的star claster 里的比较小质量的黑洞，不会马上 形成吸积盘（吸积盘的吸入速度太慢），而是由于黑洞的质量小不占主导，在cluster中在做 无规运动，不 形成盘，物质直接 掉入，快速增长质量。而由于当地密度太大，光深大，引力能释放产生的光子出不来，所以也看不到。

话说这篇文章出来，是不是意味着AGN中黑洞质量来源之谜就解决了？

精彩摘抄:

文章信息:
http://www.sciencemag.org/content/early/2014/08/06/science.1251053.abstract

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

1. Tal Alexander¹,*,
2. Priyamvada Natarajan²

+ Author Affiliations

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

1. ↵*Corresponding author. E-mail: tal.alexander@weizmann.ac.il

• 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 Gyr, is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 Gyr 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.

• Received for publication 20 January 2014.
• Accepted for publication 21 July 2014.