Related papers: Non-thermal transient sources from rotating black …

We present some results from an archival VLA study of ultraluminous X-ray source s (ULXs). These unresolved non-nuclear X-ray sources have luminosities (L_X >= 1 0^39 ergs/sec) which may require somewhat exotic explanations, such as…

Accreting sources such as AGN, X-ray binaries or gamma-ray bursts are known to be strong, high energy emitters. The hard emission is though to originate from plasmas of thermal and/or non-thermal high energy particles. Not only does this…

A new scenario for the emission of high-energy gamma-rays from dark matter annihilation around massive black holes is presented. A black hole can leave its parent halo, by means of gravitational radiation recoil, in a merger event or in the…

Black holes emit thermal radiation (Hawking effect). If after black-hole evaporation nothing else were left, an arbitrary initial state would evolve into a thermal state (`information-loss problem'). Here it is argued that the whole…

If Ultra High Energy Cosmic Rays (UHECRs) with E>4 10^{19} eV originate from BL Lacertae at cosmological distances as suggested by recent studies, the absence of the GZK cutoff can not be reconciled with Standard-Model particle properties.…

Using the generalized tortoise coordinate transformations the quantum radiation properties of Klein-Gordon scalar particles, Maxwell's electromagnetic field equations and Dirac equations are investigated in general non-stationary black…

Accreting black holes can release enormous amounts of energy to their surroundings, in various forms. Such feedback may profoundly influence a black hole's environment. After briefly reviewing the possible types of feedback, I focus on the…

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10^12 electron Volts (eV) and are…

The fundamental resonances of rapidly rotating Kerr black holes in the eikonal limit are derived analytically. We show that there exists a critical value, $\mu_c=\sqrt{{{15-\sqrt{193}}\over{2}}}$, for the dimensionless ratio $\mu\equiv m/l$…

Studies have proposed that there is evidence for cosmological coupling of black holes (BHs) with an index of $k\approx 3$; hence, BHs serve as the astrophysical source of dark energy. However, the data sample is limited for the redshifts of…

Neutrino-cooled accretion flow around a spinning black hole, produced by a compact binary merger is a promising scenario for jet formation and launching magnetically-driven outflows. Based on GW170817 gravitational wave detection by LIGO…

Core-collapse in massive stars is believed to produce a rapidly spinning black hole surrounded by a compact disk or torus. This forms an energetic MeV-nucleus inside a remnant He-core, powered by black hole-spin energy. The output produces…

The interest in the implications that astrophysical observations have for the understanding of the structure of black holes has grown since the first detection of gravitational waves. Many arguments that are put forward in order to…

Emission of particles created in the background of a rotating black hole can be greatly amplified taking away rotational energy of a black hole. This amplification affects both particles created near the horizon (due to the Hawing effect),…

The angular and spectral features of neutrinos emitted from primordial black holes (PBHs) carry key imprints of the black hole's fundamental properties. This work investigates the directional emission of neutrinos from Kerr-Newman PBHs…

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…

We analytically study the linear response of a near-extremal Kerr black hole to external scalar, electromagnetic, and gravitational field perturbations. We show that the energy density, electromagnetic field strength, and tidal force…

The relativistic viscous fluid equations describing the outflow of high temperature matter created via Hawking radiation from microscopic black holes are solved numerically for a realistic equation of state. We focus on black holes with…

Rapid, hyper-Eddington accretion is likely to power the central engines of gamma-ray bursts (GRBs). In the extreme conditions of densities and temperatures the accreting torus is cooled by neutrino emission rather than by radiation. Another…

We investigate the production of ultra-high-energy cosmic ray (UHECR) in relativistic jets from low-luminosity active galactic nuclei (LLAGN). We start by proposing a model for the UHECR contribution from the black holes (BHs) in LLAGN,…