Testing the spherical evolution of cosmic voids

TL;DR

This paper investigates how dark energy influences the evolution of cosmic voids using a spherical model, showing that dark energy delays void shell-crossing and that initial velocities are crucial for accurate modeling.

Contribution

It demonstrates the effectiveness of the spherical evolution model in predicting void profiles and highlights the importance of initial velocities in void evolution, with implications for constraining dark energy.

Findings

Dark energy suppresses peculiar velocity growth in voids.

Void shell-crossing occurs later with higher dark energy density.

Initial velocities significantly impact void evolution timing.

Abstract

We study the spherical evolution model for voids in $\Lambda$CDM, where the evolution of voids is governed by dark energy at an earlier time than that for the whole universe or in overdensities. We show that the presence of dark energy suppresses the growth of peculiar velocities, causing void shell-crossing to occur at progressively later epochs as $\Omega_{\Lambda}$ increases. We apply the spherical model to evolve the initial conditions of N-body simulated voids and compare the resulting final void profiles. We find that the model is successful in tracking the evolution of voids with radii greater than $30 h^{-1} \rm Mpc$, implying that void profiles could be used to constrain dark energy. We find that the initial peculiar velocities of voids play a significant role in shaping their evolution. Excluding the peculiar velocity in the evolution model delays the time of shell crossing.