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

Journal article

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 S1.4GHz > 1mJy 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. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Authors: Lindsay, SN; Jarvis, M; Santos, MG; Brown, M; Croom, S

• Publication status: Published
• Publisher: Blackwell Publishing Ltd
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 440
• Issue: 2
• Pages: 1527-1541
• Publication date: 2014-05-01
• DOI: 10.1093/mnras/stu354
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: surveys; large-scale structure of Universe; radio continuum: galaxies; galaxies: active