  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.
