Evolutionary Paths of Active Galactic Nuclei and Their Host Galaxies

TL;DR

This study analyzes the relationship between supermassive black holes and their host galaxies in active galactic nuclei, revealing evolutionary paths and feedback mechanisms influencing galaxy and black hole growth.

Contribution

It provides the largest dataset to date for nearby AGNs and uncovers how AGNs evolve along the black hole mass–stellar mass relation.

Findings

AGNs follow a similar $M_{\rm BH}-M_*$ relation regardless of galaxy type.

Evolutionary paths depend on initial position relative to the $M_{\rm BH}-M_*$ relation.

Feedback mechanisms vary, affecting star formation and black hole growth differently.

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.