Fossil Galaxy Groups -- Ideal Laboratories for Studying the Effects of AGN Heating

TL;DR

This study investigates fossil galaxy groups as natural laboratories for understanding AGN feedback effects on the intergalactic medium, using X-ray and radio observations to identify AGN-inflated bubbles and estimate energy injection.

Contribution

It provides the first detailed analysis of fossil groups combining X-ray and low-frequency radio data to study AGN feedback mechanisms and bubble formation.

Findings

Detection of AGN-inflated bubbles in X-ray data

Extended radio emission associated with the central AGN

Estimates of the energy injected by the AGN into the IGM

Abstract

We present the first of a sample of fossil galaxy groups with pre-existing Chandra and/or XMM-Newton X-ray observations and new or forthcoming low frequency GMRT data -- RXJ1416.4+2315 (z=0.137). Fossil galaxy groups are ideal laboratories for studying feedback mechanisms and how energy injection affects the IGM, since due to the lack of recent merging activity, we expect the IGM to be relatively pristine and affected only by any AGN activity that has occurred in the group. Our Chandra X-ray observations reveal features resembling AGN-inflated bubbles, whilst our GMRT radio data show evidence of extended emission from the central AGN that may be filling the bubble. This has enabled us to estimate the work done by the central AGN, place limits on the rates of energy injection and discuss the nature of the plasma filling the bubble.