Evolutionary Paths of Active Galactic Nuclei and Their Host Galaxies

Abstract: The tight correlations between the masses of supermassive black holes (BHs) and the properties of their host galaxies suggest that BHs coevolve with galaxies. However, what is the link between BH mass ($M_{\rm BH}$) and the properties of the host galaxies of active galactic nuclei (AGNs) in the nearby Universe? We measure stellar masses ($M_$), colors, and structural properties for $\sim11,500$ $z\leq0.35$ broad-line AGNs, nearly 40 times larger than that in any previous work. We find that early-type and late-type AGNs follow a similar $M_{\rm BH}-M_$ relation. The position of AGNs on the $M_{\rm BH}-M_$ plane is connected with the properties of star formation and BH accretion. Our results unveil the evolutionary paths of galaxies on the $M_{\rm BH}-M_$ plane: objects above the relation tend to evolve more horizontally with substantial $M_*$ growth; objects on the relation move along the local relation; and objects below the relation migrate more vertically with substantial $M_{\rm BH}$ growth. These trajectories suggest that radiative-mode feedback cannot quench the growth of BHs and their host galaxies for AGNs that lie below the relation, while kinetic-mode feedback hardly suppress long-term star formation for AGNs situated above the relation. This work provides important constraints for numerical simulations and offers a framework for studying the cosmic coevolution of supermassive BHs and their host galaxies.