1206.0732 (Roy Maartens et al.)

Relativistic corrections and non-Gaussianity in radio continuum surveys    [PDF]

Roy Maartens, Gong-Bo Zhao, David Bacon, Kazuya Koyama, Alvise Raccanelli

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. Here we extend recent works by analyzing 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 consider the continuum surveys LOFAR, EMU and WODAN, and examples of continuum surveys with the SKA. We find that the GR corrections will not be observable in LOFAR, WODAN and EMU surveys, but they produce percent-level changes for high enough sensitivity SKA surveys. The GR corrections are suppressed in all these radio continuum surveys because of the integration over redshift -- we expect that the GR corrections will be enhanced in future HI surveys. We also provide predictions for each of the radio continuum angular power spectra in the case where the primordial perturbations have local non-Gaussianity. We find that non-Gaussianity corrections to the power spectrum will dominate over GR corrections on all scales for $f_{\rm NL}\gtrsim10$.

View original: http://arxiv.org/abs/1206.0732