The environments of luminous radio-WISE selected infrared galaxies.

We have observed the environments of a population of 33 heavily dust obscured, ultraluminous, high-redshift galaxies, selected using Wide-Field Infrared Survey Explorer (WISE) and NRAO 1.4 GHz VLA Sky Survey at |$z$| > 1.3 with the infrared array camera on the Spitzer Space Telescope over |$5.12\,\mathrm{ arcmin}\times 5.12\,\mathrm{ arcmin}$| fields. Colour selections are used to quantify any potential overdensities of companion galaxies in these fields. We find no significant excess of galaxies with the standard colour selection for IRAC colours of [3.6] − [4.5] > −0.1 consistent with galaxies at |$z$| > 1.3 across the whole fields with respect to wide-area Spitzer comparison fields, but there is a >2σ statistical excess within |$\rm 0.25\,arcmin\mathrm{ }$| of the central radio-WISE galaxy. Using a colour selection of |$\rm [3.6]-[4.5]\,\,\gt\,\, 0.4$|⁠, 0.5 magnitudes redder than the standard method of selecting galaxies at |$z$| > 1.3, we find a significant overdensity, in which |$\rm 76{{\ \rm per\ cent}}$| (⁠|$\rm 33{{\ \rm per\ cent}}$|⁠) of the 33 fields have a surface density greater than the |$\rm 3\sigma$| (⁠|$\rm 5\sigma$|⁠) level. There is a statistical excess of these redder galaxies within |$\rm 0.5\,arcmin$|⁠, rising to a central peak |$\rm {\sim}2$| –4 times the average density. This implies that these galaxies are statistically linked to the radio-WISE selected galaxy, indicating similar structures to those traced by red galaxies around radio-loud active galactic nuclei. [ABSTRACT FROM AUTHOR]