The bolometric output and host-galaxy properties of obscured AGN in the XMM-COSMOS survey

TL;DR

This study analyzes the multi-wavelength properties of 255 obscured Type-2 AGN from the XMM-COSMOS survey, revealing host galaxy characteristics, bolometric outputs, and the relationship between X-ray and infrared luminosities.

Contribution

It provides a comprehensive multi-wavelength analysis of obscured AGN, including host galaxy properties, bolometric luminosities, and morphological classifications, which advances understanding of AGN-host galaxy connections.

Findings

Type-2 AGN have lower bolometric corrections than Type-1 AGN.

Host galaxies of Type-2 AGN are predominantly bulge-dominated with stellar masses >10^10 solar masses.

A correlation exists between X-ray and mid-infrared luminosities in AGN.

Abstract

We present a study of the multi-wavelength properties, from the mid-infrared to the hard X-rays, of a sample of 255 spectroscopically identified X-ray selected Type-2 AGN from the XMM-COSMOS survey. Most of them are obscured the X-ray absorbing column density is determined by either X-ray spectral analyses (for the 45% of the sample), or from hardness ratios. Spectral Energy Distributions (SEDs) are computed for all sources in the sample. The average SEDs in the optical band is dominated by the host-galaxy light, especially at low X-ray luminosities and redshifts. There is also a trend between X-ray and mid-infrared luminosity: the AGN contribution in the infrared is higher at higher X-ray luminosities. We calculate bolometric luminosities, bolometric corrections, stellar masses and star formation rates (SFRs) for these sources using a multi-component modeling to properly disentangle the emission associated to stellar light from that due to black hole accretion. For 90% of the sample we also have the morphological classifications obtained with an upgraded version of the Zurich Estimator of Structural Types (ZEST+). We find that on average Type-2 AGN have lower bolometric corrections than Type-1 AGN. Moreover, we confirm that the morphologies of AGN host-galaxies indicate that there is a preference for these Type-2 AGN to be hosted in bulge-dominated galaxies with stellar masses greater than 10^10 solar masses.