Related papers: Does the mass of a black hole decrease due to the …
An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with $p < -\rho$ grows rapidly and dominates the late-time expanding phase. The universe's energy density is so…
We address the spherical accretion of generic fluids onto black holes. We show that, if the black hole metric satisfies certain conditions, in the presence of a test fluid it is possible to derive a fully relativistic prescription for the…
We consider spherical steady accretion of the relativistic Vlasov gas onto a Schwarzschild-like black hole. We determine the expressions for the particle current density and accretion rate and present the limiting expressions for the mass…
The gravitational collapse of a pressureless fluid in general relativity (Oppenheimer-Snyder collapse) results in a black hole. The study of the same phenomenon in the brane-world scenario has shown that the exterior of the collapsing dust…
We investigate how accretion episodes onto massive black holes power quasars and AGN while they accumulate mass into the holes. We compute both the trend and the stochastic component to the trigger of the accretion events, as provided by…
Some severe constraints on asymmetric dark matter are based on the scenario that certain types of WIMPs can form mini-black holes inside neutron stars that can lead to their destruction. A crucial element for the realization of this…
We present a slowly rotating black hole with phantom global monopole by solving Einstein's field equation and find that presence of global monopole changes the structure of black hole. The metric coefficient $g_{t\phi}$ contains…
In general relativity, the interaction between a black hole and the fields around it (a process known as backreaction) proceeds via the evolution of the black holes mass and angular momentum. Analogue models of gravity, particularly fluid…
The two apparently distinct phenomena of dark energy (or late-time cosmic acceleration) and quantum gravity dominate physics on extremely low, and extremely high energies, but do not seem to have any apparent empirical connection.…
The internal structure of a slowly rotating, charged black hole that is undergoing mass inflation at its inner horizon is derived. The equations governing the angular behavior decouple from the radial behavior, so all conclusions regarding…
Observations have found black holes spanning ten orders of magnitude in mass across most of cosmic history. The Kerr black hole solution is however provisional as its behavior at infinity is incompatible with an expanding universe. Black…
We consider collision of two particles near the horizon of a nonextremal static black hole. At least one of them is accelerated. We show that the energy $E_{c.m.}$ in the center of mass can become unbounded in spite of the fact that a black…
A series of tantalizing results led to the black hole uniqueness conjecture: isolated, realistic black holes should settle down to states characterized by their spin, mass and charge. I argue that generically real black holes will also…
The influence of a possible low gravity scale, concretely through the presence of extra dimensions or additional species, on radiation properties of micro black holes is investigated. In particular, the suppression of evaporation through…
Besides having some very interesting perturbatively unstable orbits, it seems that for a Schwarzschild black hole, below $r=3M$, the force always increases inward with increasing angular momentum. Here this previously known result is…
A critique of the singularity theorems of Penrose, Hawking, and Geroch is given. It is pointed out that a gravitationally collapsing black hole acts as an ultrahigh energy particle accelerator that can accelerate particles to energies…
In light of recent evidence suggesting a nonzero present-day cosmological constant, Adams, Mbonye, & Laughlin (1999) have considered the evolution of black holes in the presence of vacuum energy. Using the assumption that Lambda remains…
Christodoulou and Rovelli have shown that the maximal interior volume of a Schwarzschild black hole linearly grows with time. Recently, their conclusion has been extended to the Reissner{-}Nordstr$\ddot{\text{o}}$m and Kerr black holes.…
I show that there is a physical limit to the mass of a black hole, above which it cannot grow through luminous accretion of gas, and so cannot appear as a quasar or active galactic nucleus. The limit is Mmax \simeq 5x10^{10}M_sun for…
Supermassive black holes are nowadays believed to reside in most local galaxies. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. I briefly review here…