It’s shown that the rotating dilaton-axion black hole solution can be obtained from GGHS static charged dilaton black hole solution via NewmanJanis method. PACS number(s): 02.30.Dk,04.20.Cv The low energy limit of the heterotic string theory gives an interesting generalization of Einstein-Maxwell theory the Einstein-Maxwell-dilaton axion gravity.The field equations of the Einstein-Maxwell-dilat...

Using a recently developed perturbation theory for uasinormal modes (QNM’s), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation. PACS numbers: 04.30.Db Typeset using REVT...

We consider a globally hyperbolic, stationary spacetime containing a black hole but no white hole. We assume, further, that the event horizon, N , of the black hole is a Killing horizon with compact cross-sections. We prove that if surface gravity is non-zero constant throughout the horizon one can globally extend such a spacetime so that the image of N is a proper subset of a regular bifurcate...

We consider a five-dimensional constant curvature black hole, which is constructed by identifying some points along a Killing vector in a five-dimensional AdS space. The black hole has the topology M4 × S, its exterior is not static and its boundary metric is of the form of a three-dimensional de Sitter space times a circle, which means that the dual conformal field theory resides on a dynamica...

With Carlip’s boundary conditions, a standard Virasoro subalgebra with corresponding central charge for static dilaton black hole obtained in the low-energy effective field theory describing string is constructed at a Killing horizon. The statistical entropies of the Garfinkle-Horowitz-Strominger dilaton black hole and the Gibbons-Maeda dilaton black hole yielded by standard Cardy formula agree...

Static black holes in two-dimensional string theory can carry tachyon hair. Configurations which are non-singular at the event horizon have non-vanishing asymptotic energy density. Such solutions can be smoothly extended through the event horizon and have non-vanishing energy flux emerging from the past singularity. Dynamical processes will not change the amount of tachyon hair on a black hole....

Einstein's equations are known to lead to the formation of black holes and spacetime singularities. This appears to be a manifestation of the mathematical phenomenon of finite-time blowup: a formation of singularities from regular initial data. We present a simple hyperbolic system of two semi-linear equations inspired by the Einstein equations. We explore a class of solutions to this system wh...

We find analytical solutions for the spherically symmetric stationary distribution of a test perfect fluid with an arbitrary equation of state in the ReissnerNordström metric. These solutions describe the stationary accretion onto black hole and the static atmosphere of a fluid around the naked singularity. The electrically charged black hole evolves to a near extreme state by accretion of a ph...

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 probe-brane approximation, 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...