Beyond the plane-parallel and Newtonian approach: Wide-angle redshift   distortions and convergence in general relativity
  We extend previous analyses of wide-angle correlations in the galaxy power spectrum in redshift space to include all general relativistic effects. These general relativistic corrections to the standard approach become important on large scales and at high redshifts, and they lead to new terms in the wide-angle correlations. We show that in principle the new terms can produce corrections of nearly 10 % on Gpc scales over the usual Newtonian approximation. General relativistic corrections will be important for future large-volume surveys such as SKA and Euclid, although the problem of cosmic variance will present a challenge in observing this. 
Daniele Bertacca, Roy Maartens, Alvise Raccanelli, Chris Clarkson
astro-ph.CO gr-qc