CMB anisotropy: deviations from Gaussianity due to non-linear gravity

Abstract

Non-linear evolution of cosmological energy density fluctuations triggers deviations from Gaussianity in the temperature distribution of the cosmic microwave background. A method to estimate these deviations is proposed. N-body simulations -- in a $Λ$CDM cosmology -- are used to simulate the strongly non-linear evolution of cosmological structures. It is proved that these simulations can be combined with the potential approximation to calculate the statistical moments of the CMB anisotropies produced by non-linear gravity. Some of these moments are computed and the resulting values are different from those corresponding to Gaussianity.

6 latex pages with mn.sty, 3 eps figures. Accepted in MNRAS