Simulating the effect of AGN feedback on the metal enrichment of galaxy clusters

TL;DR

This study uses hydrodynamical simulations to investigate how AGN feedback influences metal enrichment and thermal properties of the intracluster medium, revealing its role in galaxy cluster evolution and enrichment patterns.

Contribution

It introduces detailed chemo-dynamical simulations including various feedback mechanisms, highlighting the specific impact of AGN feedback on ICM enrichment and temperature profiles.

Findings

AGN feedback quenches star formation in brightest cluster galaxies.

It improves temperature profiles in galaxy groups.

Creates widespread metal enrichment in cluster outskirts.

Abstract

We present a study of the effect of AGN feedback on metal enrichment and thermal properties of the intracluster medium (ICM) in hydrodynamical simulations. The cosmological simulations are performed for a set of clusters using a version of the TreePM-SPH Gadget code that follows chemo-dynamical evolution by accounting for metal enrichment by different stellar populations. Besides runs not including any efficient form of energy feedback, we carry out simulations including: (i) kinetic feedback in the form of galactic winds triggered by supernova explosions; (ii) AGN feedback from gas accretion onto super-massive black holes (BHs); (iii) AGN feedback in which a 'radio mode' is included. We find that AGN feedback is able to quench star formation in the brightest cluster galaxies at z<4 and provides correct temperature profiles in the central regions of galaxy groups. However, its effect is not sufficient to create cool cores in massive clusters. AGN feedback creates a widespread enrichment in the outskirts of clusters, thanks to its efficiency in displacing enriched gas from galactic halos to the inter-galactic medium at relatively high redshift. Iron abundance profiles are in better agreement with observations, with a more pristine enrichment of the ICM around and beyond the cluster virial regions. From the pattern of the relative abundances of Silicon and Iron, we conclude that a significant fraction of ICM enrichment in simulations is contributed by a diffuse population of intra-cluster stars. Our simulations also predict that profiles of Z_Si/Z_Fe abundance ratio do not increase at least out to 0.5 R_vir. Our results clearly show that different sources of energy feedback leave distinct imprints in the enrichment pattern of the ICM, that are more evident when looking at cluster external regions.