Gravitational Collapse of a Massless Scalar Field and a Perfect Fluid with Self-Similarity of the First Kind in (2+1) Dimensions

TL;DR

This paper derives self-similar solutions for collapsing perfect fluids and massless scalar fields in 2+1 dimensions, revealing conditions under which black holes form or cosmological models emerge.

Contribution

It introduces new self-similar solutions in 2+1 dimensions for scalar fields and fluids, analyzing their properties and collapse outcomes.

Findings

Some solutions lead to black hole formation.

Others can be viewed as cosmological models.

Black holes are always formed in certain collapse scenarios.

Abstract

Self-similar solutions of a collapsing perfect fluid and a massless scalar field with kinematic self-similarity of the first kind in 2+1 dimensions are obtained. Their local and global properties of the solutions are studied. It is found that some of them represent gravitational collapse, in which black holes are always formed, and some may be interpreted as representing cosmological models.