Electromagnetic Field in Higher-Dimensional Black-Hole Spacetimes

A special test electromagnetic field in the spacetime of the higher-dimensional generally rotating NUT-(A)dS black hole is found. It is adjusted to the hidden symmetries of the background represented by the principal Killing-Yano tensor. Such electromagnetic field generalizes the field of charged black hole in four dimensions. In higher dimensions, however, the gravitational back reaction of such a field cannot be consistently solved.Comment: 8 pages, no figures; presented at the Black hole VI conference in White Point, Canada, May 12-16 2007, and at the GRG18 conference in Sydney, Australia, July 8-13 200

Linear stability of Einstein-Gauss-Bonnet static spacetimes. Part II: vector and scalar perturbations

We study the stability under linear perturbations of a class of static solutions of Einstein-Gauss-Bonnet gravity in $D=n+2$ dimensions with spatial slices of the form \Sigma_{\k}^n \times {\mathbb R}^+, \Sigma_{\k}^n an $n-$manifold of constant curvature \k. Linear perturbations for this class of space-times can be generally classified into tensor, vector and scalar types. In a previous paper, tensor perturbations were analyzed. In this paper we study vector and scalar perturbations. We show that vector perturbations can be analyzed in general using an S-deformation approach and do not introduce instabilities. On the other hand, we show by analyzing an explicit example that, contrary to what happens in Einstein gravity, scalar perturbations may lead to instabilities in black holes with spherical horizons when the Gauss-Bonnet string corrections are taken into account.Comment: 16 pages, 6 figure

Critical escape velocity of black holes from branes

In recent work we have shown that a black hole stacked on a brane escapes once it acquires a recoil velocity. This result was obtained in the {\it probe-brane} approximation, {\it i.e.}, when the tension of the brane is negligibly small. Therefore, it is not clear whether the effect of the brane tension may prevent the black hole from escaping for small recoil velocities. The question is whether a critical escape velocity exists. Here, we analyze this problem by studying the interaction between a Dirac-Nambu-Goto brane and a black hole assuming adiabatic (quasi-static) evolution. By describing the brane in a fixed black hole spacetime, which restricts our conclusions to lowest order effects in the tension, we find that the critical escape velocity does not exist for co-dimension one branes, while it does for higher co-dimension branes.Comment: 10 pages, revte

D=5 Einstein-Maxwell-Chern-Simons Black Holes

5-dimensional Einstein-Maxwell-Chern-Simons theory with Chern-Simons coefficient $\lambda=1$ has supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum. Here supersymmetry is associated with a borderline between stability and instability, since for $\lambda>1$ a rotational instability arises, where counterrotating black holes appear, whose horizon rotates in the opposite sense to the angular momentum. For $\lambda>2$ black holes are no longer uniquely characterized by their global charges, and rotating black holes with vanishing angular momentum appear.Comment: 4 pages, 4 figures, RevTeX styl

Merger Transitions in Brane--Black-Hole Systems: Criticality, Scaling, and Self-Similarity

We propose a toy model for study merger transitions in a curved spaceime with an arbitrary number of dimensions. This model includes a bulk N-dimensional static spherically symmetric black hole and a test D-dimensional brane interacting with the black hole. The brane is asymptotically flat and allows O(D-1) group of symmetry. Such a brane--black-hole (BBH) system has two different phases. The first one is formed by solutions describing a brane crossing the horizon of the bulk black hole. In this case the internal induced geometry of the brane describes D-dimensional black hole. The other phase consists of solutions for branes which do not intersect the horizon and the induced geometry does not have a horizon. We study a critical solution at the threshold of the brane-black-hole formation, and the solutions which are close to it. In particular, we demonstrate, that there exists a striking similarity of the merger transition, during which the phase of the BBH-system is changed, both with the Choptuik critical collapse and with the merger transitions in the higher dimensional caged black-hole--black-string system.Comment: 9 pages 2 figures; additional remarks and references are added at Section IX "Discussion

Remark on the effective potential of the gravitational perturbation in the black hole background projected on the brane

The polar perturbation is examined when the spacetime is expressed by a 4d metric induced from higher-dimensional Schwarzschild geometry. Since the spacetime background is not a vacuum solution of 4d Einstein equation, the various general principles are used to understand the behavior of the energy-momentum tensor under the perturbation. It is found that although the general principles fix many components, they cannot fix two components of the energy-momentum tensor. Choosing two components suitably, we derive the effective potential which has a correct 4d limit.Comment: 12 pages, no figure, CQG accepte

Black strings in (4+1)-dimensional Einstein-Yang-Mills theory

We study two classes of static uniform black string solutions in a (4+1)-dimensional SU(2) Einstein-Yang-Mills model. These configurations possess a regular event horizon and corresponds in a 4-dimensional picture to axially symmetric black hole solutions in an Einstein-Yang-Mills-Higgs-U(1)-dilaton theory. In this approach, one set of solutions possesses a nonzero magnetic charge, while the other solutions represent black holes located in between a monopole-antimonopole pair. A detailed analysis of the solutions' properties is presented, the domain of existence of the black strings being determined. New four dimensional solutions are found by boosting the five dimensional configurations. We also present an argument for the non-existence of finite mass hyperspherically symmetric black holes in SU(2) Einstein-Yang-Mills theory.Comment: 19 Revtex pages, 27 eps-figures; discussion on rotating black holes modifie

A Slowly Rotating Charged Black Hole in Five Dimensions

Black hole solutions in higher dimensional Einstein and Einstein-Maxwell gravity have been discussed by Tangherlini as well as Myers and Perry a long time ago. These solutions are the generalizations of the familiar Schwarzschild, Reissner-Nordstrom and Kerr solutions of four-dimensional general relativity. However, higher dimensional generalization of the Kerr-Newman solution in four dimensions has not been found yet. As a first step in this direction I shall report on a new solution of the Einstein-Maxwell system of equations that describes an electrically charged and slowly rotating black hole in five dimensions.Comment: Talk given at GR17: 17th International Conference on General Relativity and Gravitation, Dublin, 18-24 Jule,2004 ; Corrected typos, minor changes, new formula adde

Rotating Black Holes in Higher Dimensional Brane Worlds

A black string generaliztion of the Myers-Perry N dimensional rotating black hole is considered in an (N+1) dimensional Randall-Sundrum brane world. The black string intercepts the (N-1) brane in a N dimensional rotating black hole. We examine the diverse cases arising for various non-zero rotation components and obtain the geodesic equations for these space-time. The asymptotics of theresulting brane world geometries and their implications are discussed.Comment: 23 pages, latex, sections rewritten and references adde

Escape of black holes from the brane

TeV-scale gravity theories allow the possibility of producing small black holes at energies that soon will be explored at the LHC or at the Auger observatory. One of the expected signatures is the detection of Hawking radiation, that might eventually terminate if the black hole, once perturbed, leaves the brane. Here, we study how the `black hole plus brane' system evolves once the black hole is given an initial velocity, that mimics, for instance, the recoil due to the emission of a graviton. The results of our dynamical analysis show that the brane bends around the black hole, suggesting that the black hole eventually escapes into the extra dimensions once two portions of the brane come in contact and reconnect. This gives a dynamical mechanism for the creation of baby branes.Comment: 4 pages, 6 figure