2008/02/08 by S. Q. Park, P. Barmby, G. G. Fazio +14
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/587136
20 pages, 3 figures, Accepted to ApJ
arxiv created 2008/02/08 · openalex publication_date 2008/04/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
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 ≳ 10 22 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.