We study the environmental properties of z<1.2 radio-selected AGN belonging to the ~2 square degrees of the COSMOS field, finding that about 20% of them appear within overdense structures. AGN with P[1.4GHz]>1023.5WHz−1sr−1 are twice more likely to be found in clusters with respect to fainter sources (~38% vs ~15%), just as radio-selected AGN with stellar masses M∗>1011M⊙ are twice more likely to be found in overdense environments with respect to objects of lower mass (~24% vs ~11%). Comparisons with galaxy samples further suggest that radio-selected AGN of large stellar mass tend to avoid underdense environments more than normal galaxies with the same stellar content. Stellar masses also seem to determine the location of radio-active AGN within clusters: ~100% of the sources found as satellite galaxies have M∗<1011.3M⊙, while ~100% of the AGN coinciding with a cluster central galaxy have M∗>1011M⊙. No different location within the cluster is instead observed for AGN of various radio luminosities. Radio AGN which also emit in the MIR show a marked preference to be found as isolated galaxies (~70%) at variance with those also active in the X-ray which all seem to reside within overdensities. What emerges from our work is a scenario whereby physical processes on sub-pc and kpc scales (e.g. emission respectively related to the AGN and to star formation) are strongly interconnected with the large-scale environment of the AGN itself.
@article{arxiv.1805.06233,
title = {The environmental properties of radio-emitting AGN},
author = {M. Magliocchetti and P. Popesso and M. Brusa and M. Salvato},
journal= {arXiv preprint arXiv:1805.06233},
year = {2018}
}