相关论文: Multi-messenger emissions from Kerr black holes
We discuss ultra-high energy (UHE) cosmic rays (CR) from minor sources and their possible contribution to the extragalactic diffuse gamma-ray emission. As an illustration of minor sources we consider possible specific type of active…
The coalescence of supermassive black hole binaries occurs via the emission of gravitational waves, that can impart a substantial recoil to the merged black hole. We consider the energy dissipation, that results if the recoiling black hole…
If gamma-ray bursts are sources of ultra-high energy cosmic rays, then radiative signatures of hadronic acceleration are expected in GRB data. Observations with the Fermi Gamma-ray Space Telescope offer the best means to search for evidence…
We discuss recent results in neutrino astronomy and their implications for the cosmic-ray acceleration in relativistic outflows, such as in Active Galactic Nuclei (AGN) jets, Gamma-Ray Bursts (GRBs), and Tidal Disruption Events (TDEs). We…
With the observation of gravitational waves from merging compact binary systems, a new observing window of the universe has been opened. Most of the gravitational wave events currently detected are due to the merger of binary black hole…
We extract elegant and concise analytic formulae for the mass and rotation parameters of the Kerr black hole as well as its distance from the Earth only in terms of directly measurable quantities of the accretion disk revolving in the black…
We are motivated by the recently reported dynamical evidence of stars with short orbital periods moving around the center of the Milky Way and the corresponding hypothesis about the existence of a supermassive black hole hosted at its…
Powerful non-thermal emission has been detected coming from relativistic collimated outflows launched in the vicinity of black holes of a very wide range of masses, from few to $\sim 10^{10}$ M$_{\odot}$. At different scales along the…
The inspiral and merger of binary black holes will likely involve black holes with both unequal masses and arbitrary spins. The gravitational radiation emitted by these binaries will carry angular as well as linear momentum. A net flux of…
Perturbed Kerr black holes emit gravitational radiation, which (for the practical purposes of gravitational-wave astronomy) consists of a superposition of damped sinusoids termed quasi-normal modes. The frequencies and time-constants of the…
Multi-messenger high-energy astrophysics has currently achieved the potential to unravel the origin of cosmic rays and how sources accelerate them, their relation to the diffuse radiation in the extra-galactic space, and their role to forge…
Soon after the discovery of the Kerr metric, Penrose realized that superradiance can be exploited to extract energy from black holes. The original idea (involving the breakup of a single particle) yields only modest energy gains. A variant…
We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagnetic radiation during a binary black hole merger. This signal is generic and model-independent since it is characterized by the black hole mass…
Massive black holes (MBHs), with masses in the range 10^3-10^8 Msolar, which merge with a companion black hole of similar mass are expected to be the most powerful source of gravitational radiation in the frequency range probed by LISA. MBH…
We discuss the high energy neutrino emission from gamma-ray bursts resulting from the earliest generation (`population III') stars forming in the Universe, whose core collapses into a black hole. These gamma-ray bursts are expected to…
Production and acceleration mechanisms of ultra-high-energy cosmic rays (UHECRs) of energy $>10^{20}$eV, clearly beyond the GZK-cutoff limit remain unclear that points to exotic nature of the phenomena. Recent observations of extragalactic…
The first direct detections of gravitational waves (GWs) from black hole (BH) mergers, GW150914, GW151226 and LVT151012, give a robust lower limit $\sim 70000$ on the number of merged, highly-spinning BHs in our Galaxy. The total spin…
As a powerful source of gravitational waves (GW), a supermassive black hole (SMBH) merger may be accompanied by a relativistic jet that leads to detectable electromagnetic (EM) emission. We model the propagation of post-merger jets inside a…
A brief summary is given of an alternative interpretation of the Event Horizon Telescope observations of the massive black hole in the nucleus of the nearby galaxy M87. It is proposed that the flow is primarily powered by the black hole…
The photomeson production in ultra-high-energy cosmic-ray (UHECR) accelerators such as gamma-ray bursts and active galaxies may lead to ultra-high-energy (UHE) gamma-ray emission. We show that generation of UHE pairs in magnetized…