Radio Observations of the Hubble Deep Field South Region IV: Optical Properties of the Faint Radio Population

Abstract

The Australia Telescope Hubble Deep Field-South (ATHDFS) survey of the Hubble Deep Field South reaches sensitivities of ~10 miceoJyJy at 1.4, 2.5, 5.2 and 8.7 GHz, making the ATHDFS one of the deepest surveys ever performed with the Australia Telescope Compact Array. Here we present the optical identifications of the ATHDFS radio sources using data from the literature. We find that ~66% of the radio sources have optical counterparts to I = 23.5 mag. Deep HST imaging of the area identifies a further 12% of radio sources. We present new spectroscopic observations for 98 of the radio sources, and supplement these spectroscopic redshifts with photometric ones calculated from 5-band optical imaging. The host galaxy colors and radio-to-optical ratios indicate that low luminosity (or "radio quiet") AGN make up a significant proportion of the sub-mJy radio population, a result which is in accordance with a number of other deep radio studies. The radio-to-optical ratios of the bright (S_1.4GHz > 1 mJy) sources is consistent with a bimodal distribution.

accepted for publication in AJ

References in corpus (7)

• The Hubble Deep Field North SCUBA Super-map IV - Characterizing submillimetre galaxies using deep Spitzer imaging
• Radio imaging of the Subaru/XMM-Newton Deep Field - I. The 100-microJy catalogue, optical identifications, and the nature of the faint radio source population
• The Star Formation History of the Universe as Revealed by Deep Radio Observations
• The MicroJansky Radio Galaxy Population
• The Infrared Properties of Submillimeter Galaxies: Clues From Ultra-Deep 70 Micron Imaging
• Radio Observations of the Hubble Deep Field South Region III: The 2.5, 5.2 and 8.7 GHz Catalogues and Radio Source Properties
• AAT Imaging and Microslit Spectroscopy in the Southern Hubble Deep Field

Cited by in corpus (17)

• Radio and Millimeter Continuum Surveys and their Astrophysical Implications
• Cosmic evolution of radio selected active galactic nuclei in the COSMOS field
• The Caltech-NRAO Stripe 82 Survey (CNSS) Paper I: The Pilot Radio Transient Survey In 50 deg${}^2$
• High-resolution VLA Imaging of SDSS Stripe 82 at 1.4 GHz
• The dust un-biased cosmic star formation history from the 20 cm VLA-COSMOS survey
• Evolution of faint radio sources in the VIDEO-XMM3 field
• Deep 3 GHz Observations of the Lockman Hole North with the Very Large Array -2. Catalogue and μJy source properties
• No Evidence for Evolution in the Far-Infrared-Radio Correlation out to z ~ 2 in the eCDFS
• The Deep SWIRE Field. IV. First properties of the sub-mJy galaxy population: redshift distribution, AGN activity and star formation
• The ATLAS 5.5 GHz Survey of the Extended Chandra Deep Field South: The Second Data Release
• The ATLAS 5.5 GHz survey of the Extended Chandra Deep Field South: Catalogue, Source Counts and Spectral Indices
• The MAVERIC Survey: Radio catalogs and source counts from deep Very Large Array imaging of 25 Galactic globular clusters
• The host galaxies of micro-Jansky radio sources
• A Fully-Identified Sample of AEGIS20 Microjansky Radio Sources
• The ATLAS 9.0 GHz Survey of the Extended Chandra Deep Field South: The Faint 9.0 GHz Radio Population
• High resolution imaging of the ATLBS regions: the radio source counts
• Cosmology from LOFAR Two-metre Sky Survey Data Release 2: Counts-in-Cells Statistics