Forming massive seed black holes in high-redshift quasar host progenitors
Forming massive seed black holes in high-redshift quasar host progenitors
复制标题
DOI：
10.1093/mnras/stab692
复制
发表时间：
2021-02
影响因子：
4.8
通讯作者：
A. Lupi;Z. Haiman;M. Volonteri
中科院分区：
文献类型：
--
作者：
A. Lupi;Z. Haiman;M. Volonteri
质量为$10^9\,{\rm M_\odot}$数量级的大质量黑洞（BHs）在宇宙年龄小于1 Gyr时为明亮的类星体提供能量，这对它们的形成机制提出了强烈的限制。到目前为止，已经提出了几个场景来解释大质量黑洞的形成，从第一代恒星的低质量种子黑洞残留物到由大质量气体云快速坍缩产生的大质量种子黑洞。然而，其中一些场景在高z类星体的祖先中发生的可能性尚未得到彻底的探索。在这项工作中，我们通过将仅暗物质的n体模拟与半解析框架相结合，研究了在典型高红移类星体宿主的祖先形成和演化的超密集区域中，同步原子冷却晕对和/或动态加热（DH）迷你晕是否满足形成大质量种子黑洞的条件。我们的分析表明，这些区域的特殊条件，即强光晕集群和高恒星形成率，对于产生不可忽略的大质量种子黑洞宿主候选者至关重要：我们发现了≈1400 DH的无金属迷你光晕，其中包括一个演变成同步对并最终在z = 6时形成大质量类星体宿主晕的迷你光晕。这表明，高红移类星体宿主晕的祖先可以孕育早期的大质量黑洞种子。我们的研究结果进一步表明，多个大质量黑洞种子可能在类星体宿主的祖先体内或附近形成，可能在较低的红移下合并并产生引力波事件。
The presence of massive black holes (BHs) with masses of the order of $10^9\, {\rm M_\odot }$, powering bright quasars when the Universe was less than 1 Gyr old, poses strong constraints on their formation mechanism. Several scenarios have been proposed to date to explain massive BH formation, from the low-mass seed BH remnants of the first generation of stars to the massive seed BHs resulting from the rapid collapse of massive gas clouds. However, the plausibility of some of these scenarios to occur within the progenitors of high-z quasars has not yet been thoroughly explored. In this work, we investigate, by combining dark-matter only N-body simulations with a semi-analytic framework, whether the conditions for the formation of massive seed BHs from synchronized atomic-cooling halo pairs and/or dynamically heated (DH) mini-haloes are fulfilled in the overdense regions where the progenitors of a typical high-redshift quasar host form and evolve. Our analysis shows that the peculiar conditions in such regions, i.e. strong halo clustering and high star formation rates, are crucial to produce a non-negligible number of massive seed BH host candidates: we find ≈1400 DH metal-free mini-haloes, including one of these which evolves to a synchronized pair and ends up in the massive quasar-host halo by z = 6. This demonstrates that the progenitors of high-redshift quasar host haloes can harbour early massive seed BHs. Our results further suggest that multiple massive seed BHs may form in or near the quasar host’s progenitors, potentially merging at lower redshifts and yielding gravitational wave events.