The VLA Survey of the Chandra Deep Field South: I. Overview of the Radio Data

TL;DR

This paper presents deep 20 and 6 cm VLA radio observations of the Chandra Deep Field South, cataloging 266 sources, analyzing their multiwavelength counterparts, and exploring the connection between star formation and AGN activity at faint radio flux levels.

Contribution

It provides a comprehensive radio source catalog with multiwavelength counterparts and insights into the faint radio population, including star formation and AGN contributions, at unprecedented sensitivity levels.

Findings

Identification of 266 radio sources with optical/infrared counterparts.

Detection of 30 additional radio sources associated with X-ray sources.

Evidence of both star formation and low-luminosity AGN activity in faint radio sources.

Abstract

We report 20 and 6 cm VLA deep observations of the CDF-S including the Extended CDF-S. We discuss the radio properties of 266 cataloged radio sources, of which 198 are above a 20 cm completeness level reaching down to 43 microJy at the center of the field. Survey observations made at 6 cm over a more limited region covers the original CDF-S to a comparable level of sensitivity as the 20 cm observations. Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a further 37 in the E-CDF-S area not covered by the 1 Megasecond exposure. Using a wide range of material, we have found optical or infrared counterparts for 254 radio sources, of which 186 have either spectroscopic or photometric redshifts (Paper II). Three radio sources have no apparent counterpart at any other wavelength. Measurements of the 20 cm radio flux density at the position of each CDF-S X-ray source detected a further 30 radio sources above a conservative 3-sigma detection limit. X-ray and sub-mm observations have been traditionally used as a measure of AGN and star formation activity, respectively. These new observations probe the faint end of both the star formation and radio galaxy/AGN population, as well as the connection between the formation and evolution of stars and SMBHs. Both of the corresponding gravitational and nuclear fusion driven energy sources can lead to radio synchrotron emission. AGN and radio galaxies dominate at high flux densities. Although emission from star formation becomes more prominent at the microjansky levels reached by deep radio surveys, even for the weakest sources, we still find an apparent significant contribution from low luminosity AGN as well as from star formation.