Non-Gaussianity in the Cosmic Microwave Background Anisotropies at   Recombination in the Squeezed limit
  We estimate analytically the second-order cosmic microwave background temperature anisotropies at the recombination epoch in the squeezed limit and we deduce the contamination to the primordial local non-Gaussianity. We find that the level of contamination corresponds to f_NL^{con}=O(1) which is below the sensitivity of present experiments and smaller than the value O(5) recently claimed in the literature. 
N. Bartolo (Univ. of Padova and INFN Padova), S. Matarrese (Univ. of   Padova and INFN Padova), A. Riotto (CERN and INFN Padova)
astro-ph.CO gr-qc hep-ph hep-th