Characterization of AGN and their hosts in the Extended Groth Strip: a multiwavelength analysis

TL;DR

This study uses multiwavelength spectral energy distribution fitting to classify and analyze a large sample of AGN in the Extended Groth Strip, revealing their distribution, properties, and correlations across different wavelengths and redshifts.

Contribution

It provides the most comprehensive multiwavelength dataset for AGN in the EGS and introduces a reliable SED-based classification method distinguishing various AGN types and host galaxy contributions.

Findings

Identified five main AGN groups with different redshift distributions.

Established correlations between X-ray and UV/optical/infrared luminosities.

Found increased starburst-dominated AGN percentage in double detections.

Abstract

We have employed a reliable technique of classification of Active Galactic Nuclei (AGN) based on the fit of well-sampled spectral energy distributions (SEDs) with a complete set of AGN and starburst galaxy templates. We have compiled ultraviolet, optical, and infrared data for a sample of 116 AGN originally selected for their X-ray and mid-infrared emissions (96 with single detections and 20 with double optical counterparts). This is the most complete compilation of multiwavelength data for such a big sample of AGN in the Extended Groth Strip (EGS). Through these SEDs, we are able to obtain highly reliable photometric redshifts and to distinguish between pure and host-dominated AGN. For the objects with unique detection we find that they can be separated into five main groups, namely: Starburst-dominated AGN (24 % of the sample), Starburst-contaminated AGN (7 %), Type-1 AGN (21 %), Type-2 AGN (24 %), and Normal galaxy hosting AGN (24 %). We find these groups concentrated at different redshifts: Type-2 AGN and Normal galaxy hosting AGN are concentrated at low redshifts, whereas Starburst-dominated AGN and Type-1 AGN show a larger span. Correlations between hard/soft X-ray and ultraviolet, optical and infrared luminosities, respectively, are reported for the first time for such a sample of AGN spanning a wide range of redshifts. For the 20 objects with double detection the percentage of Starburst-dominated AGN increases up to 48%.