AEGIS: Radio and Mid-Infrared Selection of Obscured AGN Candidates

Abstract

The application of multi-wavelength 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 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-infrared power laws, or X-ray detections. Thus, if our candidates are indeed AGNs, the radio/mid-infrared selection criteria we use provide a powerful tool for identifying sources missed by other surveys.

20 pages, 3 figures, Accepted to ApJ

References in corpus (12)

• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• The All-wavelength Extended Groth Strip International Survey (AEGIS) Data Sets
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• Unveiling obscured accretion in the Chandra Deep Field South
• A catalogue of micro-Jy radio sources in northern legacy fields
• The AGN Contribution to the Mid-IR Emission of Luminous Infrared Galaxies
• AEGIS20: a radio survey of the Extended Groth Strip
• Extending the infrared radio correlation
• The X-ray emission of Lyman break galaxies
• Evidence for a large fraction of Compton-thick quasars at high redshift
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• The infrared-radio correlation of spheroid- and disc-dominated star-forming galaxies to z $\sim$ 1.5 in the COSMOS field
• A Fully-Identified Sample of AEGIS20 Microjansky Radio Sources
• Cosmic evolution of radio-excess AGNs in quiescent and star-forming galaxies across $0<z<4$
• Characterization of AGN and their hosts in the Extended Groth Strip: a multiwavelength analysis
• Identifying radio active galactic nuclei among radio-emitting galaxies
• Searching for Kardashev Type III civilisations from High $q$-Value Sources in the LoTSS-DR1 Value-added Catalogue
• XMM-Newton view of X-ray overdensities from nearby galaxy clusters: the environmental dependencies
• Radio-Infrared Correlation for Local Dusty Galaxies and Dusty AGNs from the AKARI All Sky Survey
• X-ray stacking of Lyman break galaxies in the 4\,Ms CDF-S - X-ray luminosities and star formation rates across cosmic time
• Hosts and environments: a (large-scale) radio history of AGN and star-forming galaxies