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

Lindsay, S N, Jarvis, M J, Santos, M G, Brown, M J I, Croom, S M, Driver, S P, Hopkins, A M, Liske, J, Loveday, J, Norberg, P and Robotham, A S G (2014) Galaxy and Mass Assembly: the evolution of bias in the radio source population to z 1.5. Monthly Notices of the Royal Astronomical Society, 440 (2). pp. 1527-1541. ISSN 0035-8711

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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.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Jonathan Loveday
Date Deposited: 24 Jun 2015 15:41
Last Modified: 01 Apr 2017 05:47

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