We show that black holes grow substantially by accretion at close to Eddington rates. Using a complete sample of soft X-ray selected AGNs, Grupe & Mathur (2004) have shown that narrow line Seyfert 1 galaxies, as a class, lie below the MBH–σ relation of normal galaxies. Some NLS1s, however, lie on or close to the MBH–σ relation. Here we show that not all NLS1s accrete at close to Eddington rates...

The general validity of the area law for black holes is still an open problem. We first show in detail how to complete the usually incompletely stated text-book proofs under the assumption of piecewise C-smoothness for the surface of the black hole. Then we prove that a black hole surface necessarily contains points where it is not C (called “cusps”) at any time before caustics of the horizon g...

Any probe which crosses the horizon of a black hole should be absorbed. In M(atrix) theory, for 0-brane probes of Schwarzschild black holes, we argue that the relevant absorption mechanism is a tachyon instability which sets in at the horizon. We give qualitative arguments, and some quantitative large-N calculations, in support of this claim. The tachyon instability provides an attractive mecha...

A family of black-hole solutions in the model with 1-component perfect fluid is obtained. The metric of any solution contains (n − 1) Ricci-flat “internal space” metrics and for certain equations of state (pi = ±ρ) coincides with the metric of black brane (or black hole) solution in the model with antisymmetric form. Certain examples (e.g. imitating M2 and M5 black branes) are considered. The p...

We present spherically symmetric black hole solutions for Einstein gravity coupled to anisotropic matter. We show that these black holes have arbitrarily short hair, and argue for stability by showing that they can arise from dynamical collapse. We also show that a recent ‘no short hair’ theorem does not apply to these solutions. Pacs numbers: 04.20.Jb, 04.40.Nr, 04.70.Bw Typeset using REVTEX

We study correlation functions of coset constructions by utilizing the method of gauge dressing. As an example we apply this method to the minimal models and to the Witten 2D black hole. We exhibit a striking similarity between the latter and the gravitational dressing. In particular, we look for logarithmic operators in the 2D black hole. e-mail: [email protected] e-mail: a.lewis1@...

We examine the dynamics of extended branes, carrying lower dimensional brane charges, wrapping black holes and black hole microstates in M and Type II string theory. We show that they have a universal dispersion relation typical of threshold bound states with a total energy equal to the sum of the contributions from the charges. In near-horizon geometries of black holes, these are BPS states, a...

We present spherically symmetric black hole solutions for Einstein gravity coupled to anisotropic matter. We show that these black holes have arbitrarily short hair, and argue for stability by showing that they can arise from dynamical collapse. We also show that a recent ‘no short hair’ theorem does not apply to these solutions. Pacs numbers: 04.20.Jb, 04.40.Nr, 04.70.Bw Typeset using REVTEX

We explore a classical instability of spacetimes of dimension D > 4. Firstly, we consider static solutions: generalised black holes and brane world metrics. The dangerous mode is a tensor mode on an Einstein base manifold of dimension D−2. A criterion for instability is found for the generalised Schwarzschild, AdSSchwarzschild and topological black hole spacetimes in terms of the Lichnerowicz s...

We present new solutions to the Einstein–Maxwell equations representing a class of charged distorted black holes. These solutions are static–axisymmetric and are generalizations of the distorted black hole solutions studied by Geroch and Hartle. Physically, they represent a charged black hole distorted by external matter fields. We discuss the zeroth and first law for these black holes. The fir...