University of Hertfordshire

From the same journal

From the same journal

Evolution of faint radio sources in the VIDEO-XMM3 field

Research output: Contribution to journalArticlepeer-review


  • 906884

    Accepted author manuscript, 827 KB, PDF document

  • K. McAlpine
  • M.J. Jarvis
  • D. Bonfield
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Original languageEnglish
Pages (from-to)1084-1095
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Early online date23 Sep 2013
Publication statusPublished - 1 Dec 2013


It has been speculated that low-luminosity radio-loud active galactic nuclei (AGN) have the potential to serve as an important source of AGN feedback, and may be responsible for suppressing star formation activity in massive elliptical galaxies at late times. As such the cosmic evolution of these sources is vitally important to understand the significance of such AGN feedback processes and their influence on the global star formation history of the Universe. In this paper, we present a new investigation of the evolution of faint radio sources out to z ~ 2.5. We combine a 1 square degree Very Large Array radio survey, complete to a depth of 100 μJy, with accurate 10 band photometric redshifts from the following surveys: Visible and Infrared Survey Telescope for Astronomy Deep Extragalactic Observations and Canada-France-Hawaii Telescope Legacy Survey. The results indicate that the radio population experiences mild positive evolution out to z ~ 1.2 increasing their space density by a factor of ~3, consistent with results of several previous studies. Beyond z = 1.2, there is evidence of a slowing down of this evolution. Star-forming galaxies drive the more rapid evolution at low redshifts, z < 1.2, while more slowly evolving AGN populations dominate at higher redshifts resulting in a decline in the evolution of the radio luminosity function at z > 1.2. The evolution is best fitted by pure luminosity evolution with star-forming galaxies evolving as (1 + z)2.47 ± 0.12 and AGN as (1 + z)1.18 ± 0.21M.


© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

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