The coevolution of supermassive black holes and galaxies in luminous AGN over a wide range of redshift (2302.10937v1)

Abstract: It is well known that supermassive black holes (SMBHs) and their host galaxies co-evolve. A manifestation of this co-evolution is the correlation that has been found between the SMBH mass, M${BH}$, and the galaxy bulge or stellar mass, M$$. The cosmic evolution of this relation, though, is still a matter of debate. In this work, we examine the M${BH}-$M$$ relation, using 687 X-ray luminous (median $\rm log\,[L_{X,2-10keV}(ergs^{-1})]=44.3$), broad line AGN, at $\rm 0.2<z<4.0$ (median $\rm z\approx 1.4$) that lie in the XMM-{\it{XXL}} field. Their M${BH}$ and M$$ range from $\rm 7.5<log\,[M_{BH}\,(M_\odot)]<9.5$ and $\rm 10<log\,[M_(M_\odot)]<12$, respectively. Most of the AGN live in star-forming galaxies and their Eddington ratios range from 0.01 to 1, with a median value of 0.06. Our results show that M${BH}$ and M$$ are correlated ($\rm r=0.47\pm0.21$, averaged over different redshift intervals). Our analysis also shows that the mean ratio of the M${BH}$ and M$$ does not evolve with redshift, at least up to $\rm z=2$ and has a value of $\rm log($M${BH}/$M$)=-2.44$. The majority of the AGN ($75\%$) are in a SMBH mass growth dominant phase. In these systems, the M${BH}-$M$$ correlation is weaker and their M$*$ tends to be lower (for the same M${BH}$) compared to systems that are in a galaxy mass growth phase. Our findings suggest that the growth of black hole mass occurs first, while the early stellar mass assembly may not be so efficient.