The mass density field in simulated non-Gaussian scenarios

TL;DR

This study investigates how primordial non-Gaussianity affects the mass density field in cosmological simulations, revealing that void statistics can effectively detect non-Gaussian features from early times to the present.

Contribution

It demonstrates that void-based statistics are sensitive indicators of primordial non-Gaussianity, providing a complementary method to higher-order moments for detection.

Findings

Negative tail of density PDF retains non-Gaussian signatures over time

Void volume fraction varies significantly with f_NL values

Void statistics can detect non-Gaussianity at low redshifts

Abstract

In this work we study the properties of the mass density field in the non-Gaussian world models simulated by Grossi et al. 2007. In particular we focus on the one-point density probability distribution function of the mass density field in non-Gausian models with quadratic non-linearities quantified by the usual parameter f_NL. We find that the imprints of primordial non-Gaussianity are well preserved in the negative tail of the probability function during the evolution of the density perturbation. The effect is already noticeable at redshifts as large as 4 and can be detected out to the present epoch. At z=0 we find that the fraction of the volume occupied by regions with underdensity delta < -0.9, typical of voids, is about 1.3 per cent in the Gaussian case and increases to ~2.2 per cent if f_NL=-1000 while decreases to ~0.5 per cent if f_NL=+1000. This result suggests that void-based statistics may provide a powerful method to detect non-Gaussianity even at low redshifts which is complementary to the measurements of the higher-order moments of the probability distribution function like the skewness or the kurtosis for which deviations from the Gaussian case are detected at the 25-50 per cent level.