AGN feedback in galaxy groups; radio surveys insights on the lower-mass regime
In the last two decades, significant improvement has been made in the understanding of how radio-mode AGN feedback operates in galaxy clusters. However, the vast majority of these studies involved observations of relatively small, high-mass (M> 5 x 10^14 Msun) samples. I will review recent advances in the lower-mass regime, where survey observations performed by VLA, LOFAR and MeerKAT in the radio band, in combination with eROSITA, Chandra and XMM-Newton in the X-rays, are exploited to investigate AGN feedback on the macro scale in large (N>200) samples of galaxy clusters and groups, for the first time down to masses of 2 x 10^13 Msun. A correlation exists between the cluster X-ray emission and the radio emission of the central AGN, which seemingly holds at all masses for both disturbed and relaxed objects. Brightest Cluster Galaxies hosting strong AGN radio emission are always found within 0.2 virial radii from the cluster centre, and there is evidence for an higher probability of stronger AGN being hosted in more massive systems. All these observations support the picture of a strong connection between the ICM and radio galaxies hosted in BCGs, which is also predicted by cold accretion models.