Related papers: Supernova, Hypernova and Gamma Ray Bursts
According to the internal-external shocks model for $\gamma $-ray bursts (GRBs), the GRB is produced by internal shocks within a relativistic flow while the afterglow is produced by external shocks with the ISM. We explore the early…
The favored progenitor model for Gamma-ray Bursts (GRBs) with Supernova (SN) association is the core collapse of massive stars. One possible outcome of such a collapse is a rapidly spinning, strongly magnetized neutron star ("magnetar"). We…
Gamma-ray bursts (GRBs) have puzzled astronomers since their accidental discovery in the late sixties. The BATSE detector on the COMPTON-GRO satellite has been detecting one burst per day for the last six years. Its findings have…
The postburst evolution of fireballs that produce $\gamma$-ray bursts is studied, assuming the expansion of fireballs to be adiabatic and relativistic. Numerical results as well as an approximate analytic solution for the evolution are…
We consider the explosion of supernovae and the possible production of a variety of high energy transients by delayed black hole formation in massive stars endowed with rotation. Following the launch of a ``successful'' shock by the usual…
Absorption and reprocessing of Gamma-ray burst radiation in the environment of cosmological GRBs can be used as a powerful probe of the elusive nature of their progenitors. Although it is widely accepted that long-duration GRBs are…
We propose that gamma ray bursts (GRBs) are produced by a shower of heavy blobs running into circumstellar material at highly relativistic speeds. The gamma ray emission is produced in the shocks these bullets drive into the surrounding…
We present a new model for gamma-ray bursts (GRBs) that are not only associated with supernovae but also have small baryon contamination. In this model, we assume a newborn neutron star to move outward at a kick velocity of $\sim 10^3 {\rm…
Blackbody-dominated (BBD) gamma-ray bursts (GRBs) are events characterized by long durations and the presence of a significant thermal component following the prompt emission, as well as by the absence of a typical afterglow. GRB 101225A is…
We consider accretion onto newborn black holes following the collapse of rotating massive stellar cores, at the threshold where a centrifugally supported disk gives way to nearly radial inflow for low angular momentum. For realistic initial…
Gamma-ray bursts (GRBs), associated with the collapse of massive stars or the collisions of compact objects, are the most luminous events in our universe. However, there is still much to learn about the nature of the relativistic jets…
Gamma-ray bursts (GRBs) are fascinating sources studied in modern astronomy. They are extremely luminous electromagnetic explosions in the Universe observed from cosmological distances. These unique characteristics provide a marvellous…
The recent progress in studies of gamma-ray bursts, their afterglows, and host galaxies is discussed. The emphasis is given to high-energy phenomena associated with gamma-ray burst explosions: high-energy cosmic rays, neutrinos,…
There is strong evidence for the existence of black holes(BHs) in some X-ray binaries and most galatic nuclei, based on different measuremental approaches, but black holes aren't finally identified for the lack of very firm observational…
Gamma-ray bursts (GRB) are extreme events. They are crudely classified into two groups based on their duration, namely the short and long bursts. Such a classification has proven to be useful to determine their progenitors: the merger of…
The behaviour of the afterglow (AG) of gamma-ray bursts (GRBs) directly provides, in the cannonball (CB) model, information about the environment of their progenitor stars. The well observed early temporal decline of the AG of GRB 021211 is…
The detection of delayed X-ray, optical and radio emission, "afterglow", associated with $\gamma$-ray bursts (GRBs) is consistent with fireball models, where the emission are produced by relativistic expanding blast wave, driven by…
Gamma-ray bursts are produced as a result of cataclysmic events such as the collapse of a massive star or the merger of two neutron stars. We monitored the position of the close-by gamma-ray burst GRB~190829A, which originated from a…
Short Gamma-Ray Bursts (GRBs) are explosions of cosmic origin believed to be associated with the merger of two compact objects, either two neutron stars, or a neutron star and a black hole. The presence of at least one neutron star has long…
Nearly all previous discussion on beaming effects in GRBs have assumed a conical geometry. However, more and more observations on relativistic jets in radio galaxies, active galactic nuclei, and "microquasars" in the Galaxy have shown that…