Related papers: Black hole spin down in GRB observations and Cosmo…
As one step towards a systematic modeling of the electromagnetic (EM) emission from an inspiralling black hole binary we consider a simple scenario in which the binary moves in a uniform magnetic field anchored to a distant circumbinary…
The speed gain of a test mass from taking a gravitational slingshot around a celestial object (scattering centre) increases with the latter's speed and compactness (stronger deflection of the mass' trajectory becomes possible without it…
Recently, many gravitational wave events from compact binary mergers have been detected by LIGO. Determining the final mass and spin of the remnant black holes (RBHs) is a fundamental issue and is also important in astrophysics. In this…
We quantitatively study the stationary, axisymmetric, force-free magnetospheres of spinning (Kerr) black holes (BHs) and the conditions needed for relativistic jets to be powered by the Blandford-Znajek mechanism. These jets could be from…
We study a rotating black hole with anisotropic matter and electromagnetic fields. We show that the electromagnetic field has the same form as the corresponding one in the Kerr-Newman geometry. The reason is thanks to the specific form of…
It is shown that so-called dark energy could possible be a manifestation of the gravitational vortex producing the "gravitomagnetic" (GM) force field: associated with cosmic matter rotation and inertial spacetime frame dragging. The general…
This thesis is divided in two parts, each one addressing problems that can be relevant in the study of compact objects. The first part deals with the study of a magnetized and self-gravitating gas of degenerated fermions (electrons and…
Many short GRBs show prompt tails lasting up to hundreds of seconds that can be energetically dominant over the initial sub-second spike. In this paper we develop an electromagnetic model of short GRBs that explains the two stages of the…
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the…
We study the force-free electrodynamics on rotating black holes in the Born-Infeld (BI) effective theory. The stream equation describing a steady and axisymmetric magnetosphere is derived. From its near-horizon behavior, we obtain the…
We review recent work on the Hawking radiation of rotating brane black holes, as may be produced at the LHC. We outline the methodology for calculating the fluxes of particles, energy and angular momentum by spin-0, spin-1/2 and spin-1…
The exact analytic solutions of the Maxwell equations in the exterior of a boosted rotating black hole immersed in an external magnetic field are obtained. The effect of boost as well as electromagnetic field on charged particle motion and…
The hard X-ray emission observed in accreting compact sources is believed to be produced by inverse Compton scattering of soft photons arising from the accretion disc by energetic electrons thermally distributed above the disc, the…
This work presents a comprehensive study of energy extraction via the Comisso-Asenjo magnetic reconnection mechanism from rotating charged black holes in the context of Kalb-Ramond (KR) gravity. We systematically investigate the influence…
We study the coupling of massive scalar fields to matter in orbit around rotating black holes. It is generally expected that orbiting bodies will lose energy in gravitational waves, slowly inspiralling into the black hole. Instead, we show…
Supermassive black holes are believed to be the central power house of active galactic nuclei. Applying the pulsar outer-magnetospheric particle accelerator theory to black-hole magnetospheres, we demonstrate that an electric field is…
In recent years, unprecedented progress has been achieved regarding black holes' observation through the electromagnetic channel. The images of the supermassive black holes M87$^{*}$ and Sgr A$^{*}$ released by the Event Horizon Telescope…
The process of superradiance can extract angular momentum and energy from astrophysical black holes (BHs) to populate gravitationally-bound states with an exponentially large number of light bosons. We analytically calculate superradiant…
A standard fireball/afterglow model of a gamma-ray burst relates the event to a merging neutron star binary, or a neutron star - black hole binary, which places the events far away from star forming regions, and is thought to have an energy…
Accreting black holes often show iron line emission in their X-ray spectra. When this line emission is very broad or variable then it is likely to originate from close to the black hole. The theory and observations of such broad and…