The Mid-Infrared Environments of High-Redshift Radio Galaxies
Abstract
Taking advantage of the impressive sensitivity of Spitzer to detect massive galaxies at high redshift, we study the mid-infrared environments of powerful, high-redshift radio galaxies at 1.2<z<3. Galaxy cluster member candidates were isolated using a single Spitzer/IRAC mid-infrared color criterion, [3.6]-[4.5]>-0.1 (AB), in the fields of 48 radio galaxies at 1.2<z<3. This simple IRAC color selection is effective at identifying galaxies at z>1.2. Using a counts-in-cell analysis, we identify a field as overdense when 15 or more red IRAC sources are found within 1arcmin (i.e.,~0.5Mpc at 1.2<z<3) of the radio galaxy to the 5sigma flux density limits of our IRAC data (f3.6=11.0uJy, f4.5=13.4uJy). We find that radio galaxies lie preferentially in medium to dense regions, with 73% of the targeted fields denser than average. Our (shallow) 120s data permit the rediscovery of previously known clusters and protoclusters associated with radio galaxies as well as the discovery of new promising galaxy cluster candidates at z>1.2.
Keywords
Cite
@article{arxiv.1202.4489,
title = {The Mid-Infrared Environments of High-Redshift Radio Galaxies},
author = {Audrey Galametz and Daniel Stern and Carlos De Breuck and Nina Hatch and Jack Mayo and George Miley and Alessandro Rettura and Nick Seymour and S. Adam Stanford and Joel Vernet},
journal= {arXiv preprint arXiv:1202.4489},
year = {2015}
}
Comments
14 pages, 7 figures, 3 tables, accepted for publication in ApJ