Family Of Rotating Anisotropic Fluid Solutions which Match to Kerr's Solution

TL;DR

This paper introduces a family of exact rotating anisotropic fluid solutions that satisfy energy conditions, possess Kerr-like singularities, and can be matched to Kerr solutions via thin shells with positive energy density.

Contribution

It presents a new family of rotating anisotropic fluid solutions that match Kerr solutions on thin shells, satisfying all energy conditions for certain parameters.

Findings

Solutions have Kerr-like ring singularities.

Solutions can be matched to Kerr on oblate spheroid surfaces.

Some solutions satisfy all energy conditions with positive surface density.

Abstract

We present a family of exact rotating anisotropic fluid solutions, which satisfy all energy conditions for certain values of their parameters. The components of the Ricci tensor $R_{\mu\nu}$ the eigenvalues of the tensor $R_\mu^\nu$ and the energy-momentum tensor $T_{\mu\nu}$ of the solutions are given explicitly. All members of the family have the ring singularity of Kerr's solution and most of them one or two more singularities. The solutions can be matched to the solution of Kerr on three closed surfaces, which for proper values of the parameters of the solutions approximate oblate spheroids. All matching surfaces are thin shells. For some values of a constant the surface density in one of them is positive everywhere and in this surface and in its interior all energy conditions are satisfied.