Related papers: Standard GRB, Dirty Fireballs, and the Excluded Mi…
GRB 090510, observed both by Fermi and AGILE satellites, is the first bright short-hard Gamma-Ray Burst (GRB) with an emission from the keV up to the GeV energy range. Within the Fireshell model, we interpret the faint precursor in the…
Knowledge of the bulk Lorentz factor $\Gamma_{0}$ of GRBs allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate,…
Lasting anywhere from a few milliseconds to several minutes, GRBs shine hundreds of times brighter than a typical supernova, making them briefly the brightest source of cosmic gamma-ray photons in the observable Universe. This thesis…
A long-duration gamma-ray burst (GRB) has been widely thought to arise from the collapse of a massive star, and it has been suggested that its ambient medium is a homogenous interstellar medium (ISM) or a stellar wind. There are two shocks…
Gamma-ray bursts (GRBs) are the universe's most energetic phenomena (isotropic luminosity $\sim 10^{51} - 10^{54}$ ergs/s) lasting for a very short duration ($\sim$ milliseconds - a few seconds). Even after an average of one GRB detected…
Fast radio bursts (FRBs) are bright milliseconds-duration radio bursts from cosmological distances. Despite intense observational and theoretical studies, their physical origin is still mysterious. One major obstacle is the lack of…
Fireball model of the gamma-ray bursts (GRBs) predicts generation of numerous internal shocks, which efficiently accelerate charged particles and generate relatively small-scale stochastic magnetic and electric fields. The accelerated…
We study the properties of short gamma-ray bursts (GRBs), based on the assumption that they are all connected to the binary neutron star mergers, whose formation mechanism contains a large amount of uncertainty. In particular, the merger…
GRB 131108A is a bright long Gamma-Ray Burst (GRB) detected by the Large Area Telescope and the Gamma-ray Burst Monitor on board the Fermi Gamma-ray Space Telescope. Dedicated temporal and spectral analyses reveal three $\gamma$-ray flares…
The jet compositions of gamma-ray bursts (GRBs) are very important to understand the energy dissipation and radiation mechanisms, but it remains an open question in GRB physics. In this paper, we present a systematic analysis to search for…
Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge…
Most cosmological models for gamma-ray bursts invoke the production of a ``fireball'' in a compact region, as indicated by the short time variability of the observed GRBs. The high density of $e^+e^-$ pairs in such fireballs inevitably…
Several hundred gamma-ray burst (GRB) redshifts have been determined to date. One of the other important properties-besides the distance-of the GRBs is the duration of the burst. In this paper, we analyse these two important quantities of…
The prompt optical flash recently detected accompanying GRB990123 suggests that, for at least some GRBs, gamma-ray emission is accompanied by prompt optical-UV emission with luminosity L(1-7.5eV)=10^{49}(\Delta\Omega/4\pi)erg/s, where…
(Abridged) We discuss a Gamma-ray burst (GRB) fireball with an additional energy injection, either in the form of a Poynting-flux-dominated outflow or a kinetic-energy-dominated matter shell injected after the burst. A total injection…
It was suggested that some of the short-duration Gamma-Ray Bursts (GRB) are giant flares of Soft Gamma-ray Repeaters (SGR) in nearby galaxies. To test this hypothesis, I have constructed a sample of 47 short GRBs, detected by the…
Gamma Ray Bursts (GRBs) are notorious for their diversity. Yet, they have a series of common features. The typical energy of their $\gamma$ rays is a fraction of an MeV. The energy distributions are well described by a ``Band spectrum'',…
Based on recent models of relativistic jet formation by thermal energy deposition around black hole-torus systems, the relation between the on- and off-axis appearance of short, hard gamma-ray bursts (GRBs) is discussed in terms of…
We present multiwavelength observations of the gamma-ray burst GRB 051028 detected by HETE-2 in order to derive its afterglow emission parameters and to determine the reason for its optical faintness when compared to other events.…
Whatever the ultimate energy source of gamma-ray bursts turns out to be, the resulting sequence of physical events is likely to lead to a fairly generic, almost unavoidable scenario: a relativistic fireball that dissipates its energy after…