结构形成宇宙学模拟中AGN反馈的统一模型
A unified model for AGN feedback in cosmological simulations of structure formation
摘要：
我们讨论了一个数值模型黑洞增长及其相关的反馈过程，第一次允许宇宙学模拟的结构形成自我一致地遵循建立的宇宙人口的星系和活动星系核。我们的模型假设种子黑洞存在于早期宇宙时代的形成晕的中心。然后，我们跟踪它们的增长，从气体吸积和合并与其他黑洞在宇宙时间的过程。对于活跃的黑洞，我们根据黑洞的吸积速率本身来区分两种不同的反馈模式。以高速率吸积的黑洞被假定为处于“类星体状态”，在那里我们通过将其热光度的一小部分与周围气体热耦合来模拟它们的反馈。对于低吸积率的黑洞，我们推测它们的反馈大多以机械形式发生，在那里活动星系核驱动的气泡被注入气体环境。使用我们的新模型，我们进行TreeSPH宇宙学模拟的尺度上的单个星系的大规模星系团，无论是孤立系和宇宙盒。我们表明，我们的模型产生的结果与观测约束的黑洞和恒星的质量密度在广泛的协议。我们发现，黑洞显着影响其宿主星系的演化，改变它们的恒星形成历史，它们的冷气体量和它们的颜色。此外，在星系团的核心中存在大质量黑洞，会强烈影响星系团内气体的性质，导致较浅的金属丰度和熵分布，并抑制强冷却流。[摘要]
英文摘要：
We discuss a numerical model for black hole growth and its associated feedback processes that for the first time allows cosmological simulations of structure formation to self-consistently follow the build up of the cosmic population of galaxies and active galactic nuclei. Our model assumes that seed black holes are present at early cosmic epochs at the centres of forming halos. We then track their growth from gas accretion and mergers with other black holes in the course of cosmic time. For black holes that are active, we distinguish between two distinct modes of feedback, depending on the black hole accretion rate itself. Black holes that accrete at high rates are assumed to be in a `quasar regime', where we model their feedback by thermally coupling a small fraction of their bolometric luminosity to the surrounding gas. For black holes with low accretion rates, we conjecture that most of their feedback occurs in mechanical form, where AGN-driven bubbles are injected into a gaseous environment. Using our new model, we carry out TreeSPH cosmological simulations on the scales of individual galaxies to those of massive galaxy clusters, both for isolated systems and for cosmological boxes. We demonstrate that our model produces results for the black hole and stellar mass densities in broad agreement with observational constraints. We find that the black holes significantly influence the evolution of their host galaxies, changing their star formation history, their amount of cold gas, and their colours. Also, the properties of intracluster gas are affected strongly by the presence of massive black holes in the cores of galaxy clusters, leading to shallower metallicity and entropy profiles, and to a suppression of strong cooling flows. [Abridged]
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。
