Shear-free axially symmetric dissipative fluids

TL;DR

This paper investigates shear-free, axially symmetric dissipative fluids, revealing their properties, the relationship between Weyl tensor and vorticity, and conditions under which gravitational radiation is absent, especially in geodesic cases.

Contribution

It provides a detailed analysis of shear-free dissipative fluids, highlighting the connection between Weyl tensor, vorticity, and dissipation, and examines geodesic fluids where gravitational radiation is not produced.

Findings

Magnetic part of Weyl tensor vanishes in geodesic case.

No gravitational radiation during evolution in geodesic shear-free fluids.

System evolves towards FRW spacetime if expansion is positive and dissipation is absent.

Abstract

We study the general properties of axially symmetric dissipative configurations under the shear-free condition. The link between the magnetic part of the Weyl tensor and the vorticity, as well as the role of the dissipative fluxes, are clearly exhibited. As a particular case we examine the geodesic fluid. In this latter case, the magnetic part of the Weyl tensor always vanishes, suggesting that no gravitational radiation is produced during the evolution. Also (for the geodesic case), in the absence of dissipation, the system evolves towards a FRW spacetime if the expansion scalar is positive.