Related papers: Is GRB 050904 a super-long burst?
Gamma-ray bursts detected at high energies provide valuable insights into the emission mechanisms behind these still puzzling enigmatic events. In this study, we focus on GRB 090510, which is an unusual short GRB exhibiting plateau emission…
It is demonstrated here that if the prompt GRB emission is produced by the simplest version of the external shock model, a specific relation should prevail between the observed duration, isotropic equivalent energy, and photon peak energy.…
The origin of magnetic fields that permeate the blast waves of gamma-ray bursts (GRBs) is a long-standing problem. The present paper argues that in four GRBs revealing extended emission at >100 MeV, with follow-up in the radio, optical and…
Short duration (<2 s) Gamma-ray bursts (GRBs) have been a mystery since their discovery. Until May 2005 very little was known about short GRBs, but this situation has changed rapidly in the last few months since the Swift and HETE-2…
We describe our attempt to determine if gamma-ray burst (GRB) and afterglow emissions could both arise in external shocks for simple GRBs--bursts consisting of just a few peaks in their lightcurves. We calculate peak flux and peak frequency…
Gamma-ray bursts (GRBs) have been phenomenologically classified into long and short populations based on the observed bimodal distribution of duration. Multi-wavelength and multi-messenger observations in recent years have revealed that in…
Growing evidence connects the progenitor systems of the short-hard subclass of gamma-ray bursts (GRBs) to the merger of compact object binaries composed by two neutron stars (NSs) or by a NS and a black hole (BH). The recent observation of…
There is strong evidence that long duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the Collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN)…
Simultaneous Swift and Fermi observations of gamma-ray bursts (GRBs) offer a unique broadband view of their afterglow emission, spanning more than ten decades in energy. We present the sample of X-ray flares observed by both Swift and Fermi…
The radiation physics of gamma-ray bursts (GRBs) remains an open question. Based on the simulation analysis and recent observations, it was proposed that GRB jets are composed of a narrow ultra-relativistic core surrounded by a wide…
We present the first systematic investigation of the morphological and timing properties of flares in GRBs observed by Swift/XRT. We consider a large sample drawn from all GRBs detected by Swift, INTEGRAL and HETE-2 prior to 2006 Jan 31,…
Swift-XRT observations of the X-ray emission from gamma ray bursts (GRBs) and during the GRB afterglow have led to many new results during the past two years. One of these exciting results is that approximately 1/3-1/2 of GRBs contain…
The hard X-ray and gamma-ray phenomenology of gamma-ray bursts (GRBs) can be explained by an external shock model where a single relativistic blast wave interacts with the surrounding medium. Besides reproducing the generic spectral…
Recently, the first association between an ultra-long gamma-ray burst (GRB) and a supernova is reported, i.e., GRB 111209A/SN 2011kl, which enables us to investigate the physics of central engines or even progenitors for ultra-long GRBs. In…
One of the major achievements of Swift is the discovery of the erratic X-ray flares harboring nearly half of gamma-ray bursts (GRBs), both for long-duration and short-duration categories, and both for traditional hard GRBs and soft X-ray…
The gamma-ray burst source GRB970228 has been observed after a delay of 8--12 hours in X-rays and after one day in visible and near infrared light. This marks the first detection of emission at lower frequencies following the gamma-ray…
The X-ray light curves of many gamma-ray bursts (GRBs) observed by the Swift X-Ray Telescope (XRT) have a very steep-decay component (tail) following the prompt gamma-rays in the early phase and have some erratic flares occurring at a time…
Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We…
A popular paradigm to explain the rapid temporal variability observed in gamma-ray burst (GRB) lightcurves is the internal shock model. We propose an alternative model in which the radiating fluid in the GRB shell is relativistically…
The first X-ray afterglow for a short (~30 ms), hard gamma-ray burst was detected by Swift on 9 May 2005 (GRB 050509b). No optical or radio counterpart was identified in follow-up observations. The tentative association of the GRB with a…