Signatures of Primordial Non-Gaussianity in the Large-Scale Structure of the Universe

Abstract

We discuss how primordial (e.g. inflationary) non-Gaussianity in the cosmological perturbations is left imprinted in the Large-Scale Structure of the universe. Our findings show that the information on the primordial non-Gaussianity set on super-Hubble scales flows into Post-Newtonian terms, leaving an observable imprint in the Large-Scale Structure. Future high-precision measurements of the statistics of the dark matter density and peculiar velocity fields will allow to pin down the primordial non-Gaussianity, thus representing a tool complementary to studies of the Cosmic Microwave Background anisotropies.

Figures (1)

• Figure 1: Wavenumber dependence of the non-linearity parameter $f_{\rm nl}$. The continuous and dashed-dotted lines correspond to the k-dependent part $\Delta f_{\rm nl}$ of $f_{\rm nl}$ ($f_{\rm nl}$ for $a_{\rm nl}=0$), with an angle between ${\bf k}_1$ and ${\bf k}_2$ of $\pi/3$ and $2\pi/3$ respectively. The horizontal lines show the k-independent part $|5 a_{\rm nl}/3|$ for $a_{\rm nl}=1, 10, 40, 100$.