Testing the fidelity of simulations of black hole - galaxy co-evolution at z ~ 1.5 with observations

Abstract

We examine the scaling relations between the mass of a supermassive black hole (SMBH) and its host galaxy properties at 1.2 < z < 1.7 using both observational data and simulations. Recent measurements of 32 Xray-selected broad-line Active Galactic Nucleus (AGNs) are compared with two independent state-of-the-art efforts, including the hydrodynamic simulation MassiveBlackII (MBII) and a semi-analytic model (SAM). After applying an observational selection function to the simulations, we find that both MBII and SAM agree well with the data, in terms of the central distribution. However, the dispersion in the mass ratio between black hole mass and stellar mass is significantly more consistent with the MBII prediction (∼ 0.3 dex), than with the SAM (∼ 0.7 dex), even when accounting for observational uncertainties. Hence, our observations can distinguish between the different recipes adopted in the models. The mass relations in the MBII are highly dependent on AGN feedback while the relations in the SAM are more sensitive to galaxy merger events triggering nuclear activity. Moreover, the intrinsic scatter in the mass ratio of our high-z sample is comparable to that observed in the local sample, all but ruling out the proposed scenario the correlations are purely stochastic in nature arising from some sort of cosmic central limit theorem. Our results support the hypothesis of AGN feedback being responsible for a causal link between the SMBH and its host galaxy, resulting in a tight correlation between their respective masses.

Testing the Evolution of the Correlations between Supermassive Black Holes and their Host Galaxies using Eight Strongly Lensed Quasars

“…Combining the new sample with published samples in both local and intermediate (i.e., 0.35 < z 1.2) redshift ranges, D20 strengthen the support for an evolution scenario in which the growth of BHs evolution predates that of the bulge component of the host galaxy. In a followup paper, Ding et al (2020a) compared the D20 measurements to the predictions by the numerical simulations including the hydrodynamic simulation MassiveBlackII (Khandai et al 2015) and a semi-analytic model (Menci et al 2014). The observed tightness of the scaling relations at high redshift is consistent with the hypothesis that AGN feedback drives the scaling correlations, and disfavors the hypothesis of the correlations being purely stochastic in nature.…”