Galaxy and Mass Assembly: the evolution of bias in the radio source population to z∼1.5
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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2014
- DOI:
- 10.1093/mnras/stu354
- arXiv:
- arXiv:1402.5654
- Bibcode:
- 2014MNRAS.440.1527L
- Keywords:
-
- surveys;
- galaxies: active;
- large-scale structure of Universe;
- radio continuum: galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- doi:10.1093/mnras/stu354