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arXiv 1109.3442astro-ph.COastro-ph.HE
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原始星系中中等质量种子黑洞的吸积

Accretion onto Intermediate-mass Seed Black Holes in Primordial Galaxies

Yuexing Li

摘要:

超大质量黑洞的起源在很大程度上是未知的,它们为观测到的最遥远的类星体提供动力。一种假设是,它们从第一批恒星留下的中等质量种子(~100 M_sun)迅速成长。然而,一些先前的研究认为,由于辐射反馈的强烈抑制,这些黑洞上的吸积太低,无法建立质量。在这里,我们重新检查这样一个黑洞的吸积过程嵌入在原始气体云,通过考虑广泛的物理和数值参数没有探索过。我们发现,虽然辐射加热和压力确实有效地抑制吸积,气体的自引力最终克服了反馈效应,并在云的一个自由落体时间尺度后将吸积提升到爱丁顿速率。此外,对于给定的黑洞质量,存在一个临界密度,超过该密度,吸积可以达到爱丁顿极限。此外,我们发现黑洞吸积速率与环境气体密度之间存在普遍相关性,这可能是模拟中黑洞生长的现实秘诀。

英文摘要:

The origin of the supermassive black holes that power the most distant quasars observed is largely unknown. One hypothesis is that they grew rapidly from intermediate-mass seeds (~100 M_sun) left by the first stars. However, some previous studies argued that accretion onto these black holes was too low to build up the mass due to strong suppression by radiative feedback. Here, we re-exam the accretion process of such a black hole embedded in a primordial gas cloud, by considering a wide range of physical and numerical parameters not explored before. We find that, while radiative heating and pressure indeed suppress accretion effectively, self-gravity of the gas eventually overcomes the feedback effects and boosts the accretion to the Eddington rate after one free-fall timescale of the cloud. Moreover, for a given black hole mass, there exists a critical density above which the accretion can reach Eddington limit. Furthermore, we find a universal correlation between black hole accretion rate and ambient gas density, which may serve as a realistic recipe for black hole growth in simulations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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