Related papers: Line-broadening in gravitational radiation from ga…
Coalescing binaries in distant galaxies are one of the most promising sources of gravitational waves detectable by the LIGO project.$^{[1-5]}$ They are also a copious source of neutrinos,$^{[1]}$ however these neutrino pulses are far too…
Several scenarios were suggested for the origins of gravitational-wave (GW) sources from mergers of stellar binary black holes (BBHs). Here we propose a novel origin through catalyzed formation of GW-sources from ultra-wide binaries in the…
Gamma-ray bursts are the most luminous electromagnetic events in the universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess…
We suggest that most nearby active galactic nuclei are fed by a series of small--scale, randomly--oriented accretion events. Outside a certain radius these events promote rapid star formation, while within it they fuel the supermassive…
Evidence for free precession has been observed in the radio signature of several pulsars. Freely precessing pulsars radiate gravitationally at frequencies near the rotation rate and twice the rotation rate, which for rotation frequencies…
This contribution is divided in two parts. The first part provides a text-book level introduction to gravitational radiation. The key concepts required for a discussion of gravitational-wave physics are introduced. In particular, the…
We derive the energy fluxes radiated by compact binary systems, including "hairy" black holes, in Einstein-Maxwell-dilaton theories, for circular orbits and at quadrupolar order. This enables to include in their resummed effective-one-body…
Most of the X-ray emission from luminous accreting black holes emerges from within 20 gravitational radii. The effective emission radius is several times smaller if the black hole is rapidly spinning. General Relativistic effects can then…
Traditionlly, gravitational wave emission from a coalescing binary system is computed using point mass approximations without considering any accretion disk. However, it is believed that in many of the galactic nuclei, there are…
We study gravitational radiation from various proposed gamma-ray burst (GRB) progenitor models, in particular compact mergers and massive stellar collapses. These models have in common a high angular rotation rate, and the final stage…
Precessing Gamma Jets, originated by Neutron Stars or Black Holes, may blaze to the observer leading to Gamma Bursts (GRBs) and Soft Gamma repeaters (SGRs). The thin gamma jet is born either at Supernova (SN) like events mostly at the…
Gamma Ray Bursts (GRBs) are the most relativistic objects known so far, involving, on one hand an ultra-relativistic motion with a Lorentz factor $\Gamma > 100$ and on the other hand an accreting newborn black hole. The two main routes…
It is understood that the Supernovae (SNe) associated to Gamma Ray Bursts (GRBs) are of type Ib/c. The temporal coincidence of the GRB and the SN represents still a major enigma of Relativistic Astrophysics. We elaborate here, from the…
Long-duration gamma-ray bursts (GRBs) are believed to be produced by the core collapse of massive stars and hence to be connected with supernovae (SNe). Indeed, for four pairs of GRBs and SNe, spectroscopically confirmed connection has been…
We outline the confluence of three novel theoretical fields in our modeling of Gamma-Ray Bursts (GRBs): 1) the ultrarelativistic regime of a shock front expanding with a Lorentz gamma factor $\sim 300$; 2) the quantum vacuum polarization…
We show that the complex shape of the cosmic ray (CR) spectrum, as recently measured by PAMELA and inferred from Fermi-LAT gamma-ray observations of molecular clouds in the Gould belt, can be naturally understood in terms of basic plasma…
Stars that are collapsing toward forming a black hole but appear frozen near their Schwarzschild horizon are termed "black stars". The collision of two black stars leads to gravitational radiation during the merging phase followed by a…
The emission of gravitational waves from a system of massive objects interacting on hyperbolic orbits is studied in the quadrupole approximation. Analytic expressions are derived for the gravitational radiation luminosity, the total energy…
Massive merging black holes will be the primary sources of powerful gravitational waves at low frequency, and will permit to test general relativity with candidate galaxies close to a binary black hole merger. In this paper we identify the…
Gamma-ray bursts (GRBs) of the long-duration class are the most luminous sources of electromagnetic radiation known in the Universe. They are generated by outflows of plasma ejected at near the speed of light by newly formed neutron stars…