Galaxy and Mass Assembly: the evolution of bias in the radio source population to z ∼ 1.5

S. N. Lindsay*, M. J. Jarvis, M. G. Santos, M. J. I. Brown, S. M. Croom, S. P. Driver, A. M. Hopkins, J. Liske, J. Loveday, P. Norberg, A. S. G. Robotham

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present a large-scale clustering analysis of radio galaxies in the Very Large Array Faint Images of the Radio Sky at Twenty-cm survey over the Galaxy and Mass Assembly (GAMA) survey area, limited to S1.4 GHz > 1 mJy with spectroscopic and photometric redshift limits up to r < 19.8 and <22 mag, respectively. For the GAMA spectroscopic matches, we present the redshift space and projected correlation functions, the latter of which yielding a correlation length r0 ∼ 8.2 h−1 Mpc and linear bias of ∼1.9 at z ∼ 0.34. Furthermore, we use the angular two-point correlation function w(θ) to determine spatial clustering properties at higher redshifts. We find r0 to increase from ∼6 to ∼14 h−1 Mpc between z = 0.3 and 1.55, with the corresponding bias increasing from ∼2 to ∼10 over the same range. Our results are consistent with the bias prescription implemented in the SKA Design Study simulations at low redshift, but exceed these predictions at z > 1. This is indicative of an increasing (rather than fixed) halo mass and/or active galactic nuclei fraction at higher redshifts or a larger typical halo mass for the more abundant Fanaroff and Riley Class I sources.

Original languageEnglish
Pages (from-to)1527-1541
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume440
Issue number2
Early online date23 Mar 2014
DOIs
Publication statusPublished - 11 May 2014

Keywords

  • Surveys
  • Galaxies: active
  • Large-scale structure of Universe
  • Radio continuum: galaxies
  • Digital sky survey
  • Angular-correlation function
  • Baryon acoustic-oscillations
  • Spatial correlation-function
  • 2-point correlation-function
  • Active galactic nuclei
  • QSO redshift survey
  • Data release 7
  • Clustering properties
  • Herschel-atlas

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