Effects of Massive Neutrinos and Dynamical Dark Energy on the Cluster Mass Function

TL;DR

This paper investigates how massive neutrinos and dynamical dark energy influence the distribution of galaxy clusters, using simulations to improve the modeling of the cluster mass function for cosmological constraints.

Contribution

It introduces a simulation-based analysis of the cluster mass function considering massive neutrinos and dynamical dark energy, validating a universal form with a linear power spectrum approach.

Findings

Universal mass function form accurately matches simulations.

Linear power spectrum accounts for neutrino mass-dependent suppression.

Method improves modeling of cluster abundance in cosmology.

Abstract

The presence of massive neutrinos affects the growth of large-scale structure in the universe, leaving a potentially observable imprint on the abundance and properties of massive dark matter-dominated halos. Cosmological surveys detect large numbers of these halos in the form of rich groups and clusters, using the information as an input to constraining the properties of dark energy. We use a suite of N-body simulations that include the effects of massive neutrinos as well as of dynamical dark energy to study the properties of the mass function. As in our previous work, we follow an approach valid at low neutrino mass, where the neutrino overdensities are assumed to be too small to act as a significant nonlinear source term for gravity. We study how well a universal form for the halo mass function describes our numerical results, finding that the use of an appropriate linear power spectrum within the formalism yields a good match to the simulation results, correctly accounting for the (neutrino mass-dependent) suppression of the mass function.