We argue that the statistical entropy relevant for the thermal interactions of a black hole with its surroundings is (the logarithm of) the number of quantum microstates of the hole which are distinguishable from the hole's exterior, and which correspond to a given hole's macroscopic conguration. We compute this number explicitly from rst principles, for a Schwarzschild black hole, using nonper...

Event horizons are the defining physical features of black hole spacetimes, and are of considerable interest in studying black hole dynamics. Here, we reconsider three techniques to localise event horizons in numerical spacetimes: integrating geodesics, integrating a surface, and integrating a levelset of surfaces over a volume. We implement the first two techniques and find that straightforwar...

We present a comprehensive study of TeV black hole events in Earth’s atmosphere originated by cosmic rays of very high energy. An advanced fortran Monte Carlo code is developed and used to simulate black hole extensive air showers from ultrahigh-energy neutrino-nucleon interactions. We investigate the characteristics of these events, compare the black hole air showers to standard model air show...

We discuss the observational consequences of black hole spin in X-ray binaries within the framework of the standard thin accretion disk model. When compared to theoretical flux distribution from the surface of a thin disk surrounding a Kerr black hole, the observed X-ray properties of the Galactic superluminal jet sources, GRO J1655-40 and GRS 1915+105, strongly suggest that each contains a bla...

Employing energy-momentum pseudotensor of Einstein, we obtian the energy distribution of a dyonic dilaton black hole. The energy distribution of this black hole depends on mass M , electric charge Qe, magnetic charge Qm and asymptotic value of the dilaton φ0. We also make some comparisons between the results of Virbhadra et. al. and ours. PASC:04.20.-q, 04.50,+h E-mail:[email protected]...

The stability of the Schwarzschild black hole is studied. Regge and Wheeler treated the problem first at 1957 and obtained the dynamical equations for the small perturbation. There are two kinds of perturbations: odd one and even one. Using the Painlevé coordinate, we reconsider the odd perturbation and find that: the white-hole-connected universe (r > 2m, see text) is unstable. Because the odd...

Motivated by the observed correlation between black hole masses Mbh and the velocity dispersion σ of host galaxies, we develop a theoretical model of black hole formation in galactic bulges (this paper generalizes an earlier ApJ Letter). The model assumes an initial state specified by a a uniform rotation rate Ω and a density distribution of the form ρ = aeff/2πGr 2 (so that aeff is an effectiv...

Recent observations indicate that many if not all galaxies host massive central black holes. In this paper we explore the influence of black holes on the lensing properties. We model the lens as an isothermal ellipsoid with a finite core radius plus a central black hole. We show that the presence of the black hole substantially changes the critical curves and caustics. If the black hole mass is...

The string-black hole correspondence is considered in the context of the correspondence principle proposed recently by Horowitz and Polchinski [7]. We demonstrate that the entropy of string states and the entropy of a Schwarzschild black hole can be matched including the subleading terms which depend on mass logarithmically. We argue the necessity to include the string interaction (with couplin...