The sub-mJy radio population of the E-CDFS: optical and infrared counterpart identification

Abstract

We study a sample of 883 sources detected in a deep Very Large Array survey at 1.4 GHz in the Extended Chandra Deep Field South. The paper focuses on the identification of their optical and infrared (IR) counterparts. We use a likelihood ratio technique that is particularly useful when dealing with deep optical images to minimize the number of spurious associations. We find a reliable counterpart for 95% of our radio sources. Most of the counterparts (74%) are detected at optical wavelengths, but there is a significant fraction (21%) only detectable in the IR. Combining newly acquired optical spectra with data from the literature we are able to assign a redshift to 81% of the identified radio sources (37% spectroscopic). We also investigate the X-ray properties of the radio sources using the Chandra 4 Ms and 250 ks observations. In particular, we use a stacking technique to derive the average properties of radio objects undetected in the Chandra images. The results of our analysis are collected in a new catalog containing the position of the optical/IR counterpart, the redshift information and the X-ray fluxes. It is the deepest multi-wavelength catalog of radio sources, which will be used for future study of this galaxy population.

18 pages, 11 figures, accepted for publication in ApJS, Table 3 and 5 are available in their entirety in the ancillary data

References in corpus (13)

• EAZY: A Fast, Public Photometric Redshift Code
• The GOODS-MUSIC sample: a multicolour catalog of near-IR selected galaxies in the GOODS-South field
• The Zurich Extragalactic Bayesian Redshift Analyzer (ZEBRA) and its first application: COSMOS
• The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Medium-Band optical imaging and high quality 32-band photometric redshifts in the ECDF-S
• Deep ATLAS radio observations of the CDFS-SWIRE field
• Deep U band and R imaging of GOODS-South: Observations,data reduction and first results
• A Public, K-Selected, Optical-to-Near-Infrared Catalog of the Extended Chandra Deep Field South (ECDFS) from the MUltiwavelength Survey by Yale-Chile (MUSYC)
• The young stellar population in M17 revealed by Chandra
• The VLA 1.4GHz Survey of the Extended Chandra Deep Field South: First Data Release
• The VLA Survey of the Chandra Deep Field South: I. Overview of the Radio Data
• Calibration update of the COMBO-17 CDFS catalogue
• The VLA Survey of the Chandra Deep Field South. II. Identification and host galaxy properties of submillijansky sources
• ESO Imaging Survey: Infrared Deep Public Survey

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• The XXL Survey. XLI. Radio AGN luminosity functions based on the GMRT $610\mathrm{MHz}$ continuum observations
• The AGN content of deep radio surveys and radio emission in radio-quiet AGN. Why every astronomer should care about deep radio fields