2012/06/30 by Roy Maartens, Gong-Bo Zhao, David Bacon +2 · 30 citations
Physics and Astronomy · #COSMIC cancer database #Cosmic microwave background #Cosmic variance #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Observable #Radio Astronomy Observations and Technology #Redshift #Spectral density #Weak gravitational lensing #astro-ph.CO #gr-qc
paper · pdf · doi:10.1088/1475-7516/2013/02/044
published in Journal of Cosmology and Astroparticle Physics 2013(02), 044 (Institute of Physics) · 8 pages, 6 figures; Version accepted by JCAP
arxiv created 2013/01/24 · openalex publication_date 2013/02/26 · arxiv updated 2013/03/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 non-Gaussianity. 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 auto-correlation. 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 percent-level 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 multiple-tracer 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 non-Gaussianity. We find that non-Gaussianity dominates over GR corrections, and rises above cosmic variance when f NL ≳5 for SKA continuum surveys.