Mid-infrared Identification of 6 cm Radio Source Counterparts in the Extended Groth Strip

Abstract

A new 6-cm survey of almost 0.6 square degrees to a limit of 0.55-mJy/beam (10-sigma) finds 37 isolated radio sources and 7 radio source pairs (not necessarily physical companions). IRAC counterparts are identified for at least 92% of the radio sources within the area of deep IRAC coverage, which includes 31 isolated sources and 6 pairs. This contrasts with an identification rate of <74% to R<23.95 in visible light. Eight of the IRAC galaxies have power law spectral energy distributions, implying that the mid-infrared emission comes from a powerful AGN. The remaining 26 IRAC galaxies show stellar emission in the mid-infrared, probably in most of these galaxies because the stellar emission is bright enough to outshine an underlying AGN. The infrared colors suggest that the majority of these galaxies are bulge-dominated and have redshifts between approximately 0.5 and 1.0. Visible spectra from the DEEP2 redshift survey, available for 11 galaxies, are consistent with this suggestion. The IRAC galaxies fall into two distinct groups in a color-magnitude diagram, one group (the "stripe") includes all the AGN. The other group (the "blue clump") has blue 3.6 to 8 micron colors and a small range of 8 micron magnitudes. This separation should be useful in classifying galaxies found in other radio surveys.

Accepted by AJ

References in corpus (11)

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Cited by in corpus (9)

• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• The All-wavelength Extended Groth Strip International Survey (AEGIS) Data Sets
• CANDELS Multiwavelength Catalogs: Source Identification and Photometry in the CANDELS Extended Groth Strip
• A catalog of mid-infrared sources in the Extended Groth Strip
• Active Galactic Nuclei as seen by the Spitzer Space Telescope
• Catalog of Radio Galaxies with z>0.3. I:Construction of the Sample
• Deep ugrizY Imaging and DEEP2/3 Spectroscopy: A Photometric Redshift Testbed for LSST and Public Release of Data from the DEEP3 Galaxy Redshift Survey
• A Fully-Identified Sample of AEGIS20 Microjansky Radio Sources
• The Impact of Inclination-dependent Attenuation on Ultraviolet Star Formation Rate Tracers