Dynamics of minimally coupled dark energy in spherical halos of dark matter

TL;DR

This paper investigates how scalar field dark energy behaves within dark matter halos, revealing that its dynamics depend on the effective sound speed, which influences its perturbation and role during halo evolution.

Contribution

It provides a detailed analysis of dark energy dynamics in dark matter halos, highlighting the dependence on sound speed and potential for observational constraints.

Findings

Dark energy density remains similar to background for high sound speed.

Low sound speed dark energy significantly influences halo evolution.

Properties of dark energy can help constrain sound speed through observations.

Abstract

We analyse the evolution of scalar field dark energy in the spherical halos of dark matter at the late stages of formation of gravitationally bound systems in the expanding Universe. The dynamics of quintessential dark energy at the center of dark matter halo strongly depends on the value of effective sound speed $c_s$ (in units of speed of light). If $c_s\sim1$ (classical scalar field) then the dark energy in the gravitationally bound systems is only slightly perturbed and its density is practically the same as in cosmological background. The dark energy with small value of sound speed ($c_s<0.1$), on the contrary, is important dynamical component of halo at all stages of their evolution: linear, non-linear, turnaround, collapse, virialization and later up to current epoch. These properties of dark energy can be used for constraining the value of effective sound speed $c_s$ by comparison the theoretical predictions with observational data related to the large scale gravitationally bound systems.