Relativistic corrections and nonGaussianity in radio continuum surveys
Abstract
Forthcoming radio continuum surveys will cover large volumes of the observable Universe and will reach to high redshifts, making them potentially powerful probes of dark energy, modified gravity and nonGaussianity. We consider the continuum surveys with LOFAR, WSRT and ASKAP, and examples of continuum surveys with the SKA. We extend recent work on these surveys by including redshift space distortions and lensing convergence in the radio source autocorrelation. In addition we compute the general relativistic (GR) corrections to the angular power spectrum. These GR corrections to the standard Newtonian analysis of the power spectrum become significant on scales near and beyond the Hubble scale at each redshift. We find that the GR corrections are at most percentlevel in LOFAR, WODAN and EMU surveys, but they can produce O(10%) changes for high enough sensitivity SKA continuum surveys. The signal is however dominated by cosmic variance, and multipletracer techniques will be needed to overcome this problem. The GR corrections are suppressed in continuum surveys because of the integration over redshift — we expect that GR corrections will be enhanced for future SKA HI surveys in which the source redshifts will be known. We also provide predictions for the angular power spectra in the case where the primordial perturbations have local nonGaussianity. We find that nonGaussianity dominates over GR corrections, and rises above cosmic variance when f_{NL}gtrsim5 for SKA continuum surveys.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 February 2013
 DOI:
 10.1088/14757516/2013/02/044
 arXiv:
 arXiv:1206.0732
 Bibcode:
 2013JCAP...02..044M
 Keywords:

 Astrophysics  Cosmology and Extragalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 8 pages, 6 figures