Cosmological simulations of scale-dependent primordial non-Gaussianity

TL;DR

This paper investigates how scale-dependent primordial non-Gaussianity influences cosmic structure formation through N-body simulations, revealing effects that can resemble Warm Dark Matter signatures.

Contribution

It introduces and analyzes cosmological simulations with a novel scale-dependent non-Gaussianity model, exploring its impact on structure formation and potential observational signatures.

Findings

Scale-dependent non-Gaussianity affects matter power spectrum and halo properties.

Some models mimic Warm Dark Matter effects in structure formation.

Impacts on halo mass functions and density profiles are significant.

Abstract

We present the results of a set of cosmological N-body simulations with standard $\Lambda$CDM cosmology but characterized by a scale-dependent primordial non-Gaussianity of the local type featuring a power-law dependence of the $f_{\rm NL}^{\rm loc}(k)$ at large scales followed by a saturation to a constant value at smaller scales where non-linear growth leads to the formation of collapsed cosmic structures. Such models are built to ensure consistency with current Cosmic Microwave Background bounds on primordial non-Gaussianity yet allowing for large effects of the non-Gaussian statistics on the properties of non-linear structure formation. We show the impact of such scale-dependent non-Gaussian scenarios on a wide range of properties of the resulting cosmic structures, such as the non-linear matter power spectrum, the halo and sub-halo mass functions, the concentration-mass relation, the halo and void density profiles, and we highlight for the first time that some of these models might mimic the effects of Warm Dark Matter for several of such observables