Null limits of generalised Bonnor-Swaminarayan solutions

TL;DR

This paper explores the limits of generalized Bonnor-Swaminarayan solutions, revealing how unbounded accelerations lead to impulsive gravitational waves and cosmic string dynamics, including a finite-length snapping string solution.

Contribution

It introduces a generalized class of Bonnor-Swaminarayan solutions and analyzes their limits, providing new insights into impulsive waves and cosmic string behaviors.

Findings

Unbounded accelerations produce impulsive gravitational waves.

Solutions include snapping and expanding cosmic strings.

An exact finite-length snapping string solution is derived.

Abstract

The Bonnor-Swaminarayan solutions are boost-rotation symmetric space-times which describe the motion of pairs of accelerating particles which are possibly connected to strings (struts). In an explicit and unified form we present a generalised class of such solutions with a few new observations. We then investigate the possible limits in which the accelerations become unbounded. The resulting space-times represent spherical impulsive gravitational waves with snapping or expanding cosmic strings. We also obtain an exact solution for a snapping string of finite length.