Dynamical evolutin of quintessence dark energy in collapsing dark matter halos

TL;DR

This study investigates how quintessence dark energy evolves during the collapse of dark matter halos using a novel numerical approach that covers all stages of halo formation.

Contribution

It introduces a new numerical method to analyze dark energy evolution throughout the entire spherical collapse process without separate linear or nonlinear treatments.

Findings

Dark energy perturbations evolve with redshift and depend on the collapse process.

Perturbation amplitude is about 10^{-6} for cluster-sized halos and decreases with smaller halo mass.

Dark energy perturbations can be positive or negative depending on the local properties of the quintessence field.

Abstract

In this paper, we analyze the dynamical evolution of quintessence dark energy induced by the collapse of dark matter halos. Different from other previous studies, we develop a numerical strategy which allows us to calculate the dark energy evolution for the entire history of the spherical collapse of dark matter halos, without the need of separate treatments for linear, quasi-linear and nonlinear stages of the halo formation. It is found that the dark energy perturbations evolve with redshifts, and their specific behaviors depend on the quintessence potential as well as the collapsing process. The overall energy density perturbation is at the level of $10^{-6}$ for cluster-sized halos. The perturbation amplitude decreases with the decrease of the halo mass. At a given redshift, the dark energy perturbation changes with the radius to the halo center, and can be either positive or negative depending on the contrast of $\partial_t \phi$, $\partial_r \phi$ and $\phi$ with respect to the background, where $\phi$ is the quintessence field. For shells where the contrast of $\partial_r \phi$ is dominant, the dark energy perturbation is positive and can be as high as about $10^{-5}$.