Non-Gaussianity in the cosmic microwave background anisotropies at recombination in the squeezed limit

Abstract

We estimate analytically the second-order cosmic microwave background temperature anisotropies at the recombination epoch in the squeezed limit and we deduce the contamination of the primordial local non-Gaussianity. We find that the level of contamination corresponds to f NLcon = O(1) which is below the sensitivity of present experiments and smaller than the value O(5) recently claimed in the literature. © 2012 IOP Publishing Ltd and SISSA.