Related papers: Microscopic Black Holes and Cosmic Shells
We compute the quasi-bound state spectra of ultralight scalar and vector fields around rotating black holes. These spectra are determined by the gravitational fine structure constant $\alpha$, which is the ratio of the size of the black…
This paper explores the circular geodesics of neutral test particles on an equatorial plane around a rotating black hole. After using equations of motion of scalar-tensor-vector gravity with the circular geodesics of null-like particles, we…
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the…
We investigate the thermodynamics of a general class of exact 4-dimensional asymptotically Anti-de Sitter hairy black hole solutions and show that, for a fixed temperature, there are small and large hairy black holes similar to the…
It is recently shown that, besides the Schwarzshcild black hole solution, there exist also scalarized black hole solutions in some Einstein-scalar-Gauss-Bonnet theories. In this paper, we construct analytical expressions for the metric…
We study the emission of Hawking radiation in the form of scalar fields from a (4+n)-dimensional, rotating black hole on the brane. We perform a numerical analysis to solve both the radial and angular parts of the scalar field equation, and…
One-loop renormalised quantum effective action for gravity contains quadratic in curvature terms. We have found an approximate analytic black hole solution in quadratic gravity by keeping only the radial spherically symmetric fluctuations…
We discuss in detail the semiclassical approximation for the CGHS model of two-dimensional dilatonic black holes. This is achieved by a formal expansion of the full Wheeler-DeWitt equation and the momentum constraint in powers of the…
In this second part of our series of two papers, where spacetime is modelled by a graph, where Planck size quantum black holes lie on the vertices, we consider the thermodynamics of spacetime. We formulate an equation which tells in which…
We show that Compton scattering of soft photons with energies near 100 eV in thermally stratified black-hole accretion plasmas with temperatures in the range 100 keV - 1 MeV can give rise to an X-ray spectral hardening near 10 keV. This…
We calculated the energy spectra and the fluxes of electron neutrinos in extragalactic space emitted in the process of the evaporation of primordial black holes (PBHs) in the early universe. It was assumed that PBHs are formed by a blue…
The recent 230 GHz observations by the Event Horizon Telescope have resolved the innermost structure of the M87 galaxy, revealing a ring-like feature consistent with thermal synchrotron emission from a magnetized torus surrounding a…
Primordial black holes (PBH), while still constituting a viable dark matter component, are expected to evaporate through Hawking radiation. Assuming the semi-classical approximation holds up to near the Planck scale, PBHs are expected to…
In this study we obtain the solution of the spherically symmetric de Sitter solution of black holes using a general form of distribution functions which include Gaussian, Rayleigh, and Maxwell-Boltzmann distribution as a special case. We…
A new dyonic solution for black holes with spherically symmetric configurations in general relativity is obtained. We study black holes possessing electric and magnetic charges, and the source of the gravitational field is electromagnetic…
This paper deals with the thermodynamical properties of black hole formulated in Einstein theory of relativity and associated with a nonlinear electromagnetic field. The transition of the black hole is analyzed using the parameters mass,…
Primordial black holes (PBHs) within the mass range $10^{17} - 10^{22}$ g are a favorable candidate for describing the all of the dark matter content. Towards the lower end of this mass range, the Hawking temperature, $T_{\rm H}$, of these…
The Standard Model of particle physics has been remarkably successful in describing present experimental results. However, it is assumed to be only a low-energy effective theory which will break down at higher energy scales, theoretically…
Two interesting hypotheses about black holes have been proposed. The older one states that microscopic black holes can be accountable for the observed dark matter density. The newer one states that black holes are coupled to the expansion…
Primordial Black Holes (PBHs) are capable of emitting extremely energetic particles independent of their interactions with the Standard Model. In this work, we investigate whether PBHs evaporating in the early universe could be responsible…