An improved model of redshift-space distortions around voids: application to quintessence dark energy

TL;DR

This paper enhances the modeling of redshift-space distortions around cosmic voids to improve constraints on dark energy, specifically testing quintessence models against LCDM by analyzing velocity profiles and applying analytical corrections.

Contribution

It introduces a refined model for redshift-space distortions around voids and demonstrates its application in distinguishing dark energy models using void velocity profiles.

Findings

Good agreement with fiducial cosmology after correction

Characteristic imprints of dark energy in velocity distributions

Improved systematic error reduction in cosmological parameter estimation

Abstract

Using cosmic voids to probe the growth rate of cosmic structure, and hence the nature of dark energy, is particularly interesting in the context of modified gravity theories that rely on the screening mechanism. In this work we improve the modelling of redshift-space distortions around voids in the dark matter density field, and thus reduce systematic errors in the derivation of cosmological parameters. We also show how specific types of voids can be used to better probe the growth rate, using a flexible void finder. We apply our results to test for a quintessence type of dark energy vs. a LCDM model, and find a good agreement with the fiducial cosmology after implementing an analytical correction to the radial velocity profiles around voids. We additionally outline characteristic imprints of dark energy in the dark matter velocity distributions around voids.