2008ApJ...678..744P

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 N_H≳10²²/cm2. 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.