A Catalog of Host Galaxies for WISE-Selected AGN: Connecting Host Properties with Nuclear Activity and Identifying Contaminants

TL;DR

This paper provides a comprehensive catalog of WISE-selected AGN host galaxy properties, revealing insights into their star formation, obscuration, and relation to AGN activity across a wide redshift range.

Contribution

The study introduces a large, detailed catalog of AGN host galaxy properties derived from spectral energy distribution fitting, expanding knowledge of obscured AGN and their hosts.

Findings

Most non-AGN contaminants are low-redshift, blue, high-SFR galaxies.

WISE AGN hosts at lower redshifts have lower specific SFRs than normal star-forming galaxies.

Obscuration is negatively correlated with Eddington ratio, supporting the receding torus model.

Abstract

We present a catalog of physical properties for galaxies hosting active galactic nuclei (AGN) detected by the Wide-field Infrared Survey Explorer (WISE). By fitting broadband spectral energy distributions of sources in the WISE AGN Catalog (Assef et al. 2018) with empirical galaxy and AGN templates, we derive photometric redshifts, AGN bolometric luminosities, measures of AGN obscuration, host galaxy stellar masses, and host galaxy star formation rates (SFRs) for 695,273 WISE AGN. The wide-area nature of this catalog significantly augments the known number of obscured AGN out to redshifts of z~3 and will be useful for studies focused on AGN or their host galaxy physical properties. We first show that the most likely non-AGN contaminants are galaxies at redshifts of z=0.2-0.3, with relatively blue W1-W2 colors, and with high specific SFRs for which the dust continuum emission is elevated in the W2 filter. Toward increasingly lower redshifts, WISE AGN host galaxies have systematically lower specific SFRs, relative to those of normal star forming galaxies, likely due to decreased cold gas fractions and the time delay between global star formation and AGN triggering. Finally, WISE AGN obscuration is not strongly correlated with AGN bolometric luminosity but shows a significant negative correlation with Eddington ratio. This result is consistent with a version of the `receding torus' model in which the obscuring material is located within the supermassive black hole gravitational sphere of influence and the dust inner radius increases due to radiation pressure.