The environmental properties of radio-emitting AGN
Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Date Issued
2018
Author(s)
MAGLIOCCHETTI, MANUELA
•
Popesso, P.
•
Brusa, M.
•
Salvato, M.
Abstract
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 $P[1.4 GHz]>10^{23.5} W Hz^{-1}
sr^{-1}$ 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
$M*>10^{11} M_\odot$ 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 $M*<10^{11.3} M_\odot$, while ~100% of the AGN coinciding with a
cluster central galaxy have $M*>10^{11} M_\odot$. 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.
Volume
478
Issue
3
Start page
3848
Issn Identifier
0035-8711
Ads BibCode
2018MNRAS.478.3848M
Rights
open.access