We study black hole - host galaxy correlations, and the relation between the over-massiveness (the distance from the average $M_{BH}-\sigma$ relation) of super-massive black holes (SMBHs) and star formation histories of their host galaxies in the Illustris and TNG100 simulations. We find that both simulations are able to produce black hole scaling relations in general agreement with observations at $z=0$, but with noticeable discrepancies. Both simulations show an offset from the observations for the $M_{BH}-\sigma$ relation, and the relation between $M_{BH}$ and the Sersic index. The relation between $M_{BH}$ and stellar mass $M_*$ is tighter than the observations, especially for TNG100. For massive galaxies in both simulations, the hosts of over-massive SMBHs (those above the mean $M_{BH}-\sigma$ relation) tend to have larger Sersic indices and lower baryon conversion efficiency, suggesting a multidimensional link between SMBHs and properties of their hosts. In Illustris, the hosts of over-massive SMBHs have formed earlier and have lower present-day star formation rates, in qualitative agreement with the observations for massive galaxies with $\sigma>100 \rm km/s$. For low-mass galaxies, such a correlation still holds in Illustris but does not exist in the observed data. For TNG100, the correlation between SMBH over-massiveness and star formation history is much weaker. The hosts of over-massive SMBHs generally have consistently larger star formation rates throughout history. These galaxies have higher stellar mass as well, due to the strong $M_{BH}-M_*$ correlation. Our findings show that simulated SMBH scaling relations and correlations are sensitive to features in the modeling of SMBHs.

中文翻译：

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Illustris 和 IllustrisTNG 模拟中黑洞和宿主星系之间的相关性

我们研究黑洞 - 宿主星系的相关性，以及超大质量黑洞 (SMBH) 的超大质量（与平均 $M_{BH}-\sigma$ 关系的距离）与其宿主恒星形成历史之间的关系Illustris 和 TNG100 模拟中的星系。我们发现这两种模拟都能够产生与 $z=0$ 处的观测大体一致的黑洞比例关系，但存在明显差异。两个模拟都显示了 $M_{BH}-\sigma$ 关系以及 $M_{BH}$ 与 Sersic 指数之间的关系与观测值的偏移。$M_{BH}$ 与恒星质量 $M_*$ 之间的关系比观测结果更紧密，尤其是对于 TNG100。对于两个模拟中的大质量星系，超大质量 SMBH 的宿主（高于平均 $M_{BH}-\sigma$ 关系的那些）往往具有较大的 Sersic 指数和较低的重子转换效率，表明 SMBH 与其宿主性质之间存在多维联系。在 Illustris 中，超大质量 SMBH 的宿主形成得更早，现在的恒星形成率较低，这与对 $\sigma>100 \rm km/s$ 的大质量星系的观测定性一致。对于低质量星系，这种相关性在 Illustris 中仍然成立，但在观测数据中不存在。对于 TNG100，SMBH 超大质量与恒星形成历史之间的相关性要弱得多。在整个历史中，超大质量 SMBH 的宿主通常具有更大的恒星形成率。由于 $M_{BH}-M_*$ 的强相关性，这些星系也具有更高的恒星质量。