The imprint of the interaction between dark sectors in galaxy clusters

TL;DR

This paper investigates how interactions between dark matter and dark energy influence galaxy cluster dynamics, revealing that such interactions affect cluster counts and could serve as observational signatures.

Contribution

It introduces a perturbation theory framework to analyze dark sector interactions' effects on cluster formation and abundance.

Findings

Dark sector interactions do not fully cluster dark energy.

Cluster counts depend on dark sector interactions and inhomogeneities.

Dark energy inhomogeneities leave observable signatures in cluster abundance.

Abstract

Based on perturbation theory, we study the dynamics of how dark matter and dark energy in the collapsing system approach dynamical equilibrium while interacting. We find that the interaction between dark sectors cannot ensure the dark energy to fully cluster along with dark, leading to the energy non-conservation problem in the collapsing system We examine the cluster number counts dependence on the interaction between dark sectors. Furthermore, we analyze how dark energy inhomogeneities affect cluster abundances. It is shown that cluster number counts can provide specific signature of dark sectors interaction and dark energy inhomogeneities.