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, George H. Rieke, M. L N Ashby, R. J. Ivison, A. L. Coil, S. Miyazaki

Research output: Contribution to journalArticle

21 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
Publication statusPublished - May 10 2008



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

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Park, S. Q., Barmby, P., Fazio, G. G., Nandra, K., Laird, E. S., Georgakakis, A., ... Miyazaki, S. (2008). AEGIS: Radio and mid-infrared selection of obscured AGN candidates. Astrophysical Journal, 678(2), 744-750.