Triggering Active Galactic Nuclei in galaxy clusters

TL;DR

This study models how ram pressure in galaxy clusters can trigger star formation and AGN activity, showing that specific ram pressure ranges align with observed galaxy distributions.

Contribution

It introduces a ram pressure-based triggering model for AGN and star formation, validated against SDSS observations, highlighting ram pressure as a key mechanism.

Findings

Ram pressure triggering model matches observed galaxy distributions.

Specific ram pressure thresholds are identified for triggering activity.

Ram pressure is likely an important mechanism for AGN activation in clusters.

Abstract

We model the triggering of Active Galactic Nuclei (AGN) in galaxy clusters using the semi- analytic galaxy formation model SAGE (?). We prescribe triggering methods based on the ram pressure galaxies experience as they move throughout the intracluster medium, which is hypothesized to trigger star formation and AGN activity. The clustercentric radius and velocity distribution of the simulated active galaxies produced by these models are compared with that of AGN and galaxies with intense star formation from a sample of low-redshift, relaxed clusters from the Sloan Digital Sky Survey. The ram pressure triggering model that best explains the clustercentric radius and velocity distribution of these observed galaxies has AGN and star formation triggered if $2.5\times10^{-14} < P_{ram} < 2.5\times10^{-13}$ Pa and $P_{ram} > 2P_{internal}$; this is consistent with expectations from hydrodynamical simulations of ram-pressure induced star formation. Our results show that ram pressure is likely to be an important mechanism for triggering star formation and AGN activity in clusters.