2,031 research outputs found
The double-Kerr equilibrium configurations involving one extreme object
We demonstrate the existence of equilibrium states in the limiting cases of
the double-Kerr solution when one of the constituents is an extreme object. In
the `extreme-subextreme' case the negative mass of one of the constituents is
required for the balance, whereas in the `extreme-superextreme' equilibrium
configurations both Kerr particles may have positive masses. We also show that
the well-known relation |J|=M^2 between the mass and angular momentum in the
extreme single Kerr solution ceases to be a characteristic property of the
extreme Kerr particle in a binary system.Comment: 12 pages, 3 figures, submitted to Class. Quantum Gra
On the physical interpretation of the delta=2 Tomimatsu-Sato solution
The physical properties of the Tomimatsu-Sato delta=2 spacetime are analyzed,
with emphasis on the issues of the negative mass distribution in this spacetime
and the origin of a massless ring singularity which are treated with the aid of
an equatorially asymmetric two-body configuration arising within the framework
of the analytically extended double-Kerr solution. As a by-product of this
analysis it is proved analytically that the Kerr spacetime with negative mass
always has a massless naked ring singularity off the symmetry axis accompanied
by a region with closed timelike curves, and it is also pointed out that the
Boyer-Lindquist coordinates in that case should be introduced in a different
manner than in the case of the Kerr solution with positive mass.Comment: 13 pages, 6 figures, submitted to Prog. Theor. Phy
On electromagnetic energy in Bardeen and ABG spacetimes
We demonstrate that the total energy of electromagnetic field in the Bardeen
and Ay\'on-Beato-Garc\'ia singularity-free models is equal to the mass
parameter , being therefore independent of the charge parameter . Our
result is fully congruent with the original idea of Born and Infeld to use
nonlinear electrodynamics for proving the electromagnetic nature of mass.Comment: 10 pages, 3 figure
Black hole-naked singularity dualism and the repulsion of two Kerr black holes due to spin-spin interaction
We report about the possibility for interacting Kerr sources to exist in two
different states - black holes or naked singularities - both states
characterized by the same masses and angular momenta. Another surprising
discovery reported by us is that in spite of the absence of balance between two
Kerr black holes, the latter nevertheless can repel each other, which provides
a good opportunity for experimental detection of the spin-spin repulsive force
through the observation of astrophysical black-hole binaries.Comment: 5 pages, 2 figures: a misprint in formula (3) rectified; published
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