| Title | Mid-Infrared Properties and Color Selection for X-Ray-Detected Active Galactic Nuclei in the MUSYC Extended Chandra Deep Field-South |
| Authors | Cardamone, Carolin N.; Urry, C. Megan; Damen, Maaike; van Dokkum, Pieter; Treister, Ezequiel; Labbé, Ivo; Virani, Shanil N.; Lira, Paulina; Gawiser, Eric |
| Bibcode | 2008ApJ...680..130C Search ADS ↗ |
| Abstract | We present the mid-infrared colors of X-ray-detected AGNs and explore mid-infrared selection criteria. Using a statistical matching technique, the likelihood ratio, over 900 IRAC counterparts were identified with a new MUSYC X-ray source catalog that includes ~1000 published X-ray sources in the Chandra Deep Field-South and Extended Chandra Deep Field-South. Most X-ray-selected AGNs have IRAC spectral shapes consistent with power-law slopes, fν propto να, and display a wide range of colors, -2 <= α <= 2. Although X-ray sources typically fit to redder (more negative α) power laws than non-X-ray-detected galaxies, more than 50% do have flat or blue (galaxy-like) spectral shapes in the observed 3-8 μm band. Only a quarter of the X-ray-selected AGNs detected at 24 μm are well fit by featureless red power laws in the observed 3.6-24 μm, likely the subset of our sample whose infrared spectra are dominated by emission from the central AGN region. Most IRAC color selection criteria fail to identify the majority of X-ray-selected AGNs, finding only the more luminous AGNs, the majority of which have broad emission lines. In deep surveys, these color selection criteria select 10%-20% of the entire galaxy population and miss many moderate-luminosity AGNs. |
| Objects | 1012 Objects Search NED ↙ |
