Singularities in the Kerr-Newman and charged $\delta=2$ Tomimatsu-Sato spacetimes endowed with negative mass

TL;DR

This paper investigates the singularity structures of negative mass Kerr-Newman and charged delta=2 Tomimatsu-Sato spacetimes, revealing massless ring singularities outside the ergoregion and within regions of closed timelike curves.

Contribution

It provides a detailed analysis of singularities in negative mass solutions, including explicit polynomial forms for the charged delta=2 Tomimatsu-Sato spacetime.

Findings

Massless ring singularity located off the symmetry axis.

Singularities lie outside the ergoregion.

Shared characteristics between Kerr-Newman and Tomimatsu-Sato solutions.

Abstract

The Kerr-Newman solution with negative mass is shown to develop a massless ring singularity off the symmetry axis. The singularity is located inside the region with closed timelike curves which has topology of a torus and lies outside the ergoregion. These characteristics are also shared by the charged Tomimatsu-Sato delta=2 solution with negative total mass to which in particular a simple form in terms of four polynomials is provided.