发表机构
Center for Physical Sciences and Technology; Astronomical Observatory, Vilnius University（立陶宛物理与工程技术中心; 维尔纽斯大学天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过预测混沌吸积下黑洞的指数增长时标并与高红移观测比较，证明恒星质量种子经混沌吸积可解释早期超大质量黑洞的快速增长，无需大质量种子或超爱丁顿增长。
AI 中文摘要
超大质量黑洞（SMBH）的起源仍存在争议，相关假说涵盖从大质量种子到超爱丁顿增长再到混沌吸积等。近期对极高红移超大质量黑洞的发现对其可能的起源和增长情景施加了约束。我们研究了混沌吸积情景能否解释最极端的早期超大质量黑洞质量。我们预测了在缓慢自转的暗物质晕中，黑洞以混沌方式吸积时的指数增长时标，在该晕中，不相关的气体流入维持低自转，从而维持低辐射效率。我们将这一预测与所有已知红移z>7的超大质量黑洞质量估计所隐含的增长时标和种子质量进行了比较，并与这类暗物质晕中预期的供给和反馈条件进行了对比。我们发现，在7.6<z<10.6期间，最庞大的超大质量黑洞可能增长得非常高效，其指数增长时标τ约为32百万年，这与混沌吸积预测一致，前提是增长几乎是连续的。所有具有维里质量估计的高红移超大质量黑洞都可能由质量M_seed≲100太阳质量的种子增长而来。我们描述了供给此类黑洞的质量储库的演化，表明风驱动的反馈最终会移除大部分气体，并在z≈7.5时改变黑洞的增长模式。我们针对高红移超大质量黑洞的自转、宿主星系相关性及可观测对应体做出了几项预测，这些预测将我们的模型与其他替代模型区分开来，并将在不久的将来得到检验。来自恒星质量种子的混沌吸积仍是已知最早超大质量黑洞的可行起源，无需引入大质量种子或超爱丁顿增长。
英文摘要
The origin of supermassive black holes (SMBHs) is still debated, with hypotheses ranging from massive seeds to super-Eddington growth to chaotic accretion. Recent discoveries of very high redshift SMBHs constrain their possible origin and growth scenarios. We investigate whether the chaotic accretion scenario can explain the most extreme high-redshift SMBH masses. We predicted the exponential growth timescale of black holes accreting chaotically in a slowly-spinning dark matter halo, in which uncorrelated gas inflows maintain a low spin and hence a low radiative efficiency. We compared this prediction against the growth timescales and seed masses implied by a compilation of all known SMBH mass estimates at $z>7$ and against the feeding and feedback conditions expected in such haloes. We found that in the period $7.6 < z < 10.6$, the most massive SMBHs likely grew very efficiently, with an exponential growth timescale $τ\sim 32$~Myr, which is consistent with chaotic accretion predictions provided that growth was almost continuous. All high-redshift SMBHs with virial mass estimates could have grown from seeds with $M_{\rm seed} \lesssim 100 \, \msun$. We describe the evolution of the mass reservoir feeding such a black hole, suggesting that wind-driven feedback eventually removes most of the gas and changes the growth mode of black holes at $z \sim 7.5$. We make several predictions regarding the spins, host-galaxy correlations, and observable counterparts of high-redshift SMBHs that distinguish our model from its alternatives. These predictions will be testable in the near future. Chaotic accretion from stellar-mass seeds remains a viable origin for the earliest known SMBHs, without invoking massive seeds or super-Eddington growth.
Comments7 pages main text + 2 appendix, 2 figures; accepted for publication in A&A
