Second-order matter perturbations in a CDM cosmology and non-Gaussianity

International audienceWe obtain exact expressions for the effect of primordial non-Gaussianity on the matter density perturbation up to second order in a ΛCDM cosmology, fully accounting for the general relativistic corrections arising on scales comparable with the Hubble radius. We present our results both in the Poisson gauge and in the comoving and synchronous gauge, which are relevant for comparison to different cosmological observables