184 research outputs found
Interior of Nonuniform Black Strings
We consider nonuniform black strings inside their event horizon. We present
numerical evidence, that the singularity touches the horizon as the horizon
topology changing transition is reached.Comment: 4 pages, 5 figue
New Regular Solutions with Axial Symmetry in Einstein-Yang-Mills Theory
We construct new regular solutions in Einstein-Yang-Mills theory. They are
static, axially symmetric and asymptotically flat. They are characterized by a
pair of integers (k,n), where k is related to the polar angle and to the
azimuthal angle. The known spherically and axially symmetric EYM solutions have
k=1. For k>1 new solutions arise, which form two branches. They exist above a
minimal value of n, that increases with k. The solutions on the lower mass
branch are related to certain solutions of Einstein-Yang-Mills-Higgs theory,
where the nodes of the Higgs field form rings.Comment: 11 pages, 7 figure
The Gregory-Laflamme instability and non-uniform generalizations of NUT strings
We explore via linearized perturbation theory the Gregory-Laflamme
instability of the NUT string (i.e the D=4 Lorentzian NUT solution uplifted to
five dimensions). Our results indicate that the Gregory-Laflamme instability
persists in the presence of a NUT charge , the critical length of the
extra-dimension increasing with for the same value of mass. The non-uniform
branch of NUT strings is numerically extended into the full nonlinear regime.Comment: 10 pages, 3 figure
Scalarized Hairy Black Holes
In the presence of a complex scalar field scalar-tensor theory allows for
scalarized rotating hairy black holes. We exhibit the domain of existence for
these scalarized black holes, which is bounded by scalarized rotating boson
stars and ordinary hairy black holes. We discuss the global properties of these
solutions. Like their counterparts in general relativity, their angular
momentum may exceed the Kerr bound, and their ergosurfaces may consist of a
sphere and a ring, i.e., form an ergo-Saturn.Comment: 11 pages, 4 figure
magnetized static, balanced black holes with event horizon topology
We construct static, nonextremal black hole solutions of the Einstein-Maxwell
equations in spacetime dimensions, with an event horizon of topology. These configurations are asymptotically flat, the U(1) field
being purely magnetic, with a spherical distribution of monopole charges but no
net charge measured at infinity. They can be viewed as generalizations of the
static dipole black ring, sharing its basic properties, in particular the
presence of a conical singularity. The magnetized version of these solutions is
constructed by applying a Harrison transformation, which puts them into an
external magnetic field. For , balanced configurations approaching
asymptotically a Melvin universe background are found for a critical value of
the background magnetic field.Comment: 12 pages, 2 figure
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