The spacetime outside a source of gravitational radiation: The axially symmetric null fluid

TL;DR

This paper models the spacetime outside an axially symmetric, radiating source, generalizing the Vaidya metric to include axial symmetry and null fluid effects, highlighting the role of vorticity in gravitational radiation.

Contribution

It introduces a generalized exterior metric for axially symmetric sources emitting gravitational radiation, incorporating null fluid and analyzing vorticity's influence.

Findings

Vorticity is linked to gravitational radiation presence.

The generalized metric reduces to Vaidya in spherical symmetry.

The model captures dissipative processes in axially symmetric spacetimes.

Abstract

We carry out a study of the exterior of an axially and reflection symmetric source of gravitational radiation. The exterior of such a source is filled with a null fluid produced by the dissipative processes inherent to the emission of gravitational radiation, thereby representing a generalization of the Vaidya metric for axially and reflection symmetric spacetimes. The role of the vorticity, and its relationship with the presence of gravitational radiation is put in evidence. The spherically symmetric case (Vaidya) is, asymptotically, recovered within the context of the $1+3$ formalism.