University of Hertfordshire

From the same journal

From the same journal

Evolution in the bias of faint radio sources to z ~ 2.2

Research output: Contribution to journalArticlepeer-review


  • 906880

    Accepted author manuscript, 671 KB, PDF document

  • S. N. Lindsay
  • M.J. Jarvis
  • K. McAlpine
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Original languageEnglish
Pages (from-to)2322-2332
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Early online date4 Apr 2014
Publication statusPublished - 21 May 2014


Quantifying how the baryonic matter traces the underlying dark matter distribution is key to both understanding galaxy formation and our ability to constrain the cosmological model. Using the cross-correlation function of radio and near-infrared galaxies, we present a large-scale clustering analysis of radio galaxies to z ~ 2.2. We measure the angular auto-correlation function of Ks<23.5 galaxies in the VISTA Deep Extragalactic Observations (VIDEO-XMM3) field with photometric redshifts out to z = 4 using VIDEO and CFHTLS (Canada-France-Hawaii Telescope Legacy Survey) photometry in the near-infrared and optical. We then use the cross-correlation function of these sources with 766 radio sources at S1.4>90μJy to infer linear bias of radio galaxies in four redshift bins. We find that the bias evolves from b = 0.57 ± 0.06 at z ~ 0.3 to 8.55 ± 3.11 at z ~ 2.2. Furthermore, we separate the radio sources into subsamples to determine how the bias is dependent on the radio luminosity, and find a bias which is significantly higher than predicted by the simulations of Wilman et al., and consistent with the lower luminosity but more abundant FR-I population having a similar bias to the highly luminous but rare FR-IIs. Our results are suggestive of a higher mass, particularly for FR-I sources than assumed in simulations, especially towards higher redshift.

ID: 7399216