Singular sources in the Demianski-Newman spacetimes

TL;DR

This paper extends the analysis of singular regions from NUT solutions to Demianski-Newman spacetimes, revealing that the effect of the NUT parameter creates semi-infinite singularities with specific mass, charge, and angular momentum distributions.

Contribution

It provides exact formulas for mass, charge, and angular momentum distributions in Demianski-Newman solutions, generalizing previous NUT solution analyses with new multipole moment expressions.

Findings

NUT parameter induces semi-infinite singularities with infinite angular momenta.

Electromagnetic fields add electric and magnetic charges to singularities.

Derived explicit formulas for multipole moments in Demianski-Newman spacetimes.

Abstract

The analysis of singular regions in the NUT solutions carried out in the recent paper (Manko and Ruiz, 2005 Class. Quantum Grav. 22, p.3555) is now extended to the Demianski-Newman vacuum and electrovacuum spacetimes. We show that the effect which produces the NUT parameter in a more general situation remains essentially the same as in the purely NUT solutions: it introduces the semi-infinite singularities of infinite angular momenta and positive or negative masses depending on the interrelations between the parameters; the presence of the electromagnetic field additionally endows the singularities with electric and magnetic charges. The exact formulae describing the mass, charges and angular momentum distributions in the Demianski-Newman solutions are obtained and concise general expressions P_n=(m+i\nu)(ia)^n, Q_n=(q+ib)(ia)^n for the entire set of the respective Beig-Simon multipole moments are derived. These moments correspond to a unique choice of the integration constant in the expression of the metric function \omega which is different from the original choice made by Demianski and Newman.