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Relativistic corrections and non-Gaussianity in radio continuum surveys

Maartens, Roy and Zhao, Gong-Bo and Bacon, David and Koyama, Kazuya and Raccanelli, Alvise (2013) Relativistic corrections and non-Gaussianity in radio continuum surveys. Journal of Cosmology and Astroparticle Physics, 2013 (2). Art. No. 044. ISSN 1475-7516.

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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.

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Additional Information:© 2013 IOP Publishing Ltd and Sissa Medialab srl. Received September 2, 2012. Revised January 23, 2013. Accepted January 23, 2013. Published February 26, 2013. We thank Matt Jarvis for helpful discussions. RM was supported by the South African Square Kilometre Array Project and National Research Foundation. RM, GZ, DB, KK were supported by the U.K. Science & Technology Facilities Council (grant no. ST/H002774/1) and by a Royal Society (U.K.)/ National Research Foundation (SA) exchange grant. KK was also supported by the European Research Council and the Leverhulme Trust. Part of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
South African Square Kilometre Array ProjectUNSPECIFIED
National Research Foundation of KoreaUNSPECIFIED
Science and Technology Facilities Council (STFC)ST/H002774/1
European Research Council (ERC)UNSPECIFIED
Leverhulme TrustUNSPECIFIED
Subject Keywords:cluster counts, galaxy clustering, non-gaussianity
Issue or Number:2
Classification Code:PACS: 98.62.Py, 98.80.Jk, 04.20.-q, 95.36.+x
Record Number:CaltechAUTHORS:20130409-084545952
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Official Citation:Relativistic corrections and non-Gaussianity in radio continuum surveys Roy Maartens et al JCAP02(2013)044
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37816
Deposited By: Ruth Sustaita
Deposited On:09 Apr 2013 16:23
Last Modified:03 Oct 2019 04:51

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