Swimming against the current: Simulations of central AGN evolution in dynamic galaxy clusters

TL;DR

This study uses 3D hydrodynamical simulations to explore how central AGN jets influence galaxy clusters, revealing that cluster gas motions disrupt jets, distribute energy broadly, and that AGN luminosity and duration affect energy deposition and observable features.

Contribution

It provides new insights into how AGN jet power and activity duration impact energy distribution and observable structures in galaxy clusters through detailed simulations.

Findings

Cluster gas motions disrupt AGN jets.

Multiple X-ray bubbles can form from long-duration AGN.

Energy deposition depends on AGN luminosity and duration.

Abstract

We present a series of three-dimensional hydrodynamical simulations of central AGN driven jets in a dynamic, cosmologically evolved galaxy cluster. Extending previous work, we study jet powers ranging from L_jet = 10^44 erg/s to L_jet = 10^46 erg/s and in duration from 30 Myr to 200 Myr. We find that large-scale motions of cluster gas disrupt the AGN jets, causing energy to be distributed throughout the centre of the cluster, rather than confined to a narrow angle around the jet axis. Disruption of the jet also leads to the appearance of multiple disconnected X-ray bubbles from a long-duration AGN with a constant luminosity. This implies that observations of multiple bubbles in a cluster are not necessarily an expression of the AGN duty cycle. We find that the "sphere of influence" of the AGN, the radial scale within which the cluster is strongly affected by the jet, scales as R ~ L_jet^(1/3). Increasing the duration of AGN activity does not increase the radius affected by the AGN significantly, but does change the magnitude of the AGN's effects. How an AGN delivers energy to a cluster will determine where that energy is deposited: a high luminosity is needed to heat material outside the core of the cluster, while a low-luminosity, long-duration AGN is more efficient at heating the inner few tens of kpc.