Title: Black hole clustering and duty cycles in the Illustris simulation Show Chinese title

Title: 黑洞聚类与Illustris模拟中的开尔文周期

Abstract: We use the high-resolution cosmological simulation Illustris to investigate the clustering of supermassive black holes across cosmic time, the link between black hole clustering and host halo masses, and the implications for black hole duty cycles. Our predicted black hole correlation length and bias match the observational data very well across the full redshift range probed. Black hole clustering is strongly luminosity-dependent on small, 1-halo scales, with some moderate dependence on larger scales of a few Mpc at intermediate redshifts. We find black hole clustering to evolve only weakly with redshift, initially following the behaviour of their hosts. However below z ~ 2 black hole clustering increases faster than that of their hosts, which leads to a significant overestimate of the clustering-predicted host halo mass. The full distribution of host halo masses is very wide, including a low-mass tail extending up to an order of magnitude below the naive prediction for minimum host mass. Our black hole duty cycles follow a power-law dependence on black hole mass and decrease with redshift, and we provide accurate analytic fits to these. The increase in clustering amplitude at late times, however, means that duty cycle estimates based on black hole clustering can overestimate duty cycles substantially, by more than two orders of magnitude. We find the best agreement when the minimum host mass is assumed to be $10^{11.2} M_\odot$ , which provides an accurate measure across all redshifts and luminosity ranges probed by our simulation. Show Chinese abstract

Abstract: 我们利用高分辨率宇宙学模拟Illustris研究了宇宙时间跨度内超大质量黑洞的聚类情况，以及黑洞聚类与宿主晕质量之间的联系，并探讨了其对黑洞活动周期的影响。 我们的预测结果显示，黑洞相关长度和偏倚在整个红移范围内很好地匹配观测数据。 黑洞聚类在小尺度（1-晕圈尺度）上强烈依赖于亮度，在中间红移处较大尺度（几兆秒差距）上也表现出适度依赖性。 我们发现黑洞聚类随红移的演化较弱，最初遵循宿主的行为。 然而，在红移低于约2时，黑洞聚类的增长速度比其宿主快，这导致由聚类预测的宿主晕质量有显著高估。 宿主晕质量的完整分布非常宽泛，包括一个低质量尾部，其范围可达到最低宿主质量朴素预测值的一个数量级以下。 我们的黑洞活动周期随黑洞质量呈幂律依赖关系，并随红移减小，我们为此提供了准确的解析拟合。 然而，晚期聚类幅度的增加意味着基于黑洞聚类估算活动周期可能会高估活动周期，误差超过两个数量级。 我们发现当假设最小宿主质量为$10^{11.2} M_\odot$时，得到最佳一致性，这为我们模拟中所有探测到的红移和亮度范围内提供了一个准确的测量值。