The Evolution of AGN in Groups and Clusters

TL;DR

This paper investigates how active galactic nuclei (AGN) evolve in galaxy groups and clusters, revealing significant increases in AGN fractions over cosmic time and their relation to star-forming galaxies.

Contribution

It presents new observations showing the evolution of AGN fractions in clusters and groups from the local universe to z~1, highlighting environmental effects on black hole growth.

Findings

AGN fraction in clusters increases by a factor of eight from z~0 to z~1

Cluster AGN fraction remains below field AGN fraction across redshifts

Groups also show substantial AGN evolution over time

Abstract

The evolution of AGN in groups and clusters provides important information about how their black holes grow, the extent to which galaxies and black holes coevolve in dense environments, and has implications for feedback in the local universe and at the epoch of cluster assembly. I describe new observations and analysis that demonstrates that the AGN fraction in clusters increases by a factor of eight from the local universe to z~1 and that this evolution is consistent with the evolution of star-forming galaxies in clusters. The cluster AGN fraction remains approximately an order of magnitude below the field AGN fraction over this entire range, while a preliminary analysis of groups indicates that they too undergo substantial evolution.