Related papers: Dynamical Evolution of Gamma-Ray Burst Remnants wi…
Numerous reports have been made of features, either in emission or absorption, in the 10 - 1000 keV spectra of some gamma-ray bursts. Originally interpreted in the context of Galactic neutron star models as cyclotron line emission and $e^+…
(Abridged) We present the results of three dimensional calculations for the MHD evolution of an adiabatic supernova remnant in both a uniform and turbulent interstellar medium using the RIEMANN framework of Balsara. In the uniform case,…
We present the first unrestricted, three-dimensional relativistic hydrodynamical calculations of the blob of gas associated with the jet producing a gamma-ray burst. We investigate the deceleration phase of the blob corresponding to the…
We propose simple, explicit, analytical approximations for the kinematics of an adiabatic blast wave propagating in an exponentially stratified ambient medium, and for the onset of radiative cooling, which ends the adiabatic era. Our…
Many cosmological models of GRBs envision the energy source to be a cataclysmic stellar event leading to a relativistically expanding fireball. Particles are thought to be accelerated at shocks and produce nonthermal radiation. The highly…
Depending upon the various models and assumptions, the existing literature on Gamma Ray Bursts (GRBs) mentions that the gross theoretical value of the duration of the burst in the hydrodynamical models is tau~r^2/(eta^2 c), where r is the…
Gamma-Ray Bursts (GRBs) are the must violent explosions after the Big-Bang. Their high energy radiation can potentially carry information about the most inner part of the accretion disk of a collapsing star, ionize the surrounding material…
Galama et al. have recently reported their follow-up measurements of the radio afterglow (AG) of the Gamma Ray Burst (GRB) 991208, up to 293 days after burst, and their reanalysis of the broad-band AG, in the framework of standard fireball…
We study numerically the evolution of an adiabatic relativistic fireball expanding into a cold uniform medium. We follow the stages of initial free expansion and acceleration, coasting and then deceleration and slowing down to a…
Many cosmological models of gamma-ray bursts (GRBs) assume that a single relativistic shell carries kinetic energy away from the source and later converts it into gamma rays, perhaps by interactions with the interstellar medium or by shocks…
Context:A significant fraction of progenitors for long gamma-ray bursts (GRBs) are believed to be massive stars. The investigation of long GRBs therefore requires modeling the propagation of ultra-relativistic blastwaves through the…
Recent gamma-ray burst observations have revealed late-time, highly energetic events which deviate from the simplest expectations of the standard fireball picture. Instead they may indicate that the central engine is active or restarted at…
The aim of this paper is to refine some results concerning the blow-up of solutions of the exponential reaction-diffusion equation. We consider solutions that blow-up in finite time, but continue to exist as weak solutions beyond the…
The fraction of a fireball kinetic kinetic energy that can be radiated away by internal shocks is sensitive to the amplitude of initial fluctuations in the fireball. We give a simple analytical description for dissipation of…
We consider the interaction between a relativistic fireball and material assumed to be still located just outside the progenitor star. Only a small fraction of the expected mass is sufficient to efficiently decelerate the fireball, leading…
The prompt emission of gamma-ray bursts has yet defied any simple explanation, despite the presence of a rich observational material and great theoretical efforts. Here we show that all the types of spectral evolution and spectral shapes…
Many gamma ray bursts (GRBs) have been observed with the Burst-Alert and X-Ray telescopes of the Swift satellite. The successive `pulses' of these GRBs end with a fast decline and a fast spectral softening, until they are overtaken by…
Recently, several new correlations between gamma ray burst (GRB) observables have been discovered. Like previously well established correlations, they challenge GRB models. Here we show that in the cannonball (CB) model of GRBs, these newly…
The principal paradigm for gamma-ray bursts suggest that the prompt transient gamma-ray signal arises from multiple shocks internal to the relativistic expansion. This paper illustrates some properties of diffusive acceleration at…
The recent detection of delayed X-ray and optical emission, ``afterglow,'' associated with gamma-ray bursts (GRBs) supports models, where the bursts are produced by relativistic expanding blastwaves, ``fireballs,'' at cosmological…