Formation of Three-Dimensional Black Strings from Gravitational Collapse of Dust Cloud

TL;DR

This paper investigates the gravitational collapse of cylindrical dust clouds in three-dimensional string theory, demonstrating that such collapse can form black strings or naked singularities within finite time, depending on initial conditions.

Contribution

It introduces new junction conditions for the dilaton and metrics, and analyzes the collapse outcomes in three-dimensional low-energy string theory.

Findings

Dust cloud collapse always forms a black string with an event horizon.

Collapse can also produce a naked singularity within finite time.

The results depend on initial data choices.

Abstract

We study the formation of black strings from a gravitational collapse of cylindrical dust clouds in the three-dimensional low-energy string theory. New junction conditions for the dilaton as well as two junction conditions for metrics and extrinsic curvatures between both regions of the clouds are presented. As a result, it is found that the collapsing dust cloud always collapses to a black string within a finite collapse time, and then a curvature singularity formed at origin is cloaked by an event horizon. Moreover, it is also shown that the collapse process can form a naked singularity within finite time, regardless of the choice of initial data.