The Void Abundance with Non-Gaussian Primordial Perturbations

TL;DR

This paper investigates how non-Gaussian initial conditions affect the abundance of cosmic voids, providing a method to constrain non-Gaussianity parameters using large-scale structure surveys.

Contribution

It introduces a Press-Schechter-like approach to quantify void abundance dependence on non-Gaussianity parameters for different bispectrum models.

Findings

Void abundance increases with negative skewness in initial conditions.

Current surveys can probe non-Gaussianity parameters as small as fnl < 10.

Void counts can distinguish between local and equilateral bispectrum models.

Abstract

We use a Press-Schechter-like calculation to study how the abundance of voids changes in models with non-Gaussian initial conditions. While a positive skewness increases the cluster abundance, a negative skewness does the same for the void abundance. We determine the dependence of the void abundance on the non-Gaussianity parameter fnl for the local-model bispectrum-which approximates the bispectrum in some multi-field inflation models-and for the equilateral bispectrum, which approximates the bispectrum in e.g. string-inspired DBI models of inflation. We show that the void abundance in large-scale-structure surveys currently being considered should probe values as small as fnl < 10 and fnl^eq < 30, over distance scales ~10 Mpc.