Characterization of Active Galactic Nuclei and Their Hosts in the Extended Groth Strip: A Multiwavelength Analysis

Abstract

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