Abstract
The application of multiwavelength selection techniques is crucial for discovering a complete and unbiased set of active galactic nuclei (AGNs). Here, we select a sample of 72 AGN candidates in the extended Groth strip (EGS) using deep radio and mid-infrared (mid-IR) data from the Very Large Array (VLA) and the Spitzer Space Telescope, and analyze their properties across other wavelengths. Only 30% of these sources are detected in deep 200 ks Chandra X-Ray Observatory pointings. The X-ray-detected sources demonstrate moderate obscuration with column densities of NH ≳ 1022 cm-2. A stacked image of sources undetected by Chandra shows low levels of X-ray activity, suggesting they may be faint or obscured AGNs. Less than 40% of our sample are selected as AGNs with optical broad lines, mid-IR power laws, or X-ray detections. Thus, if our candidates are indeed AGNs, then the radio/mid-IR selection criteria we use provide a powerful tool for identifying sources missed by other surveys.
Original language | English (US) |
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Pages (from-to) | 744-750 |
Number of pages | 7 |
Journal | Astrophysical Journal |
Volume | 678 |
Issue number | 2 |
DOIs | |
State | Published - May 10 2008 |
Keywords
- Galaxies: active
- Infrared: galaxies
- Radio continuum: galaxies
- X-rays: galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science