AEGIS: Radio and mid-infrared selection of obscured AGN candidates

S. Q. Park, P. Barmby, G. G. Fazio, K. Nandra, E. S. Laird, A. Georgakakis, D. Rosario, S. P. Willner, G. H. Rieke, M. L.N. Ashby, R. J. Ivison, A. L. Coil, S. Miyazaki

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


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 languageEnglish (US)
Pages (from-to)744-750
Number of pages7
JournalAstrophysical Journal
Issue number2
StatePublished - May 10 2008


  • Galaxies: active
  • Infrared: galaxies
  • Radio continuum: galaxies
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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