Gravitational collapse of Matter in the presence of Scalar field Dark energy

TL;DR

This paper investigates how coupled scalar field dark energy influences the gravitational collapse of dark matter regions, revealing conditions under which overdense areas either collapse or expand, affecting cosmic structure formation.

Contribution

It introduces a model of gravitational collapse with coupled scalar field dark energy, analyzing boundary conditions and the impact on dark matter evolution and structure formation.

Findings

Some overdense regions avoid collapse and expand eternally.

Dark energy evolution is altered by non-minimal coupling.

Coupled dark energy impacts dark matter virialization.

Abstract

This study examines the gravitational collapse of an overdense dark matter region in a coupled scalar field dark energy scenario within a flat FLRW background. It finds that, depending on the initial conditions, some overdense regions avoid collapse and expand eternally with the background. The interior overdense region follows a closed FLRW metric, while its boundary is described by generalized Vaidya spacetime, which allows flux across the boundary while preserving the homogeneity of dark energy inside. Dark matter evolves as cold dark matter, but in non-minimal coupling, the modified Klein-Gordon equation alters dark energy evolution. The results highlight the impact of coupled dark energy on dark matter virialization and cosmic structure formation.