# Effects of dark matter pressure on the ellipticity of cosmic voids

## TL;DR

This paper investigates how dark matter pressure influences the shapes of cosmic voids, showing that increased pressure results in more spherical voids through theoretical modeling and calculations.

## Contribution

It introduces a novel analysis of dark matter pressure effects on cosmic void ellipticity using the dark matter equation of state and linear perturbation theory.

## Key findings

- Dark matter pressure makes cosmic voids more spherical.
- The linear growth of density perturbations is affected by dark matter pressure.
- The probability distribution of void ellipticity shifts towards rounder shapes.

## Abstract

The dark matter in or around the cosmic voids affects their shapes. The thermodynamical properties of dark matter can alter the ellipticity of cosmic voids. Here, applying the dark matter equation of state from the pseudo-isothermal density profile of galaxies, we explore the shapes of cosmic voids with the non zero pressure dark matter in different cosmological models. For this purpose, the linear growth of density perturbation in the presence of dark matter pressure is calculated. In addition, the matter transfer function considering the dark matter pressure, as well as the linear matter power spectrum in the presence of the dark matter pressure are presented. Employing these results, the probability density distribution for the ellipticity of cosmic voids with the non zero pressure dark matter is calculated. Our calculations verify that the dark matter pressure leads to more spherical shapes for the cosmic voids.