Related papers: Pulsed Gamma-Ray-Burst Afterglows
The standard model of afterglow production by the forward shock wave is not supported by recent observations. We propose a model in which the forward shock is invisible and afterglow is emitted by a long-lived reverse shock in the burst…
The deaths of massive stars are sometimes accompanied by the launch of highly relativistic and collimated jets. If the jet is pointed towards Earth, we observe a "prompt" gamma-ray burst due to internal shocks or magnetic reconnection…
The successful launch and operation of NASA's Swift Gamma-Ray Burst Explorer open a new era for the multi-wavelength study of the very early afterglow phase of gamma-ray bursts (GRBs). GRB early afterglow information is essential to explore…
The dynamics of the origin of gamma-ray emissions in gamma-ray bursts (GRBs) remains an enigma. Through a joint analysis of GRB 180427A, observed by the Fermi Gamma-ray Space Telescope and AstroSat's Cadmium Zinc Telluride Imager, we…
Understanding the origin and diversity of emission processes responsible for Gamma-ray Bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the…
Evidence suggests that the gamma-ray burst (GRB) ejecta is likely magnetized, although the degree of magnetization of the ejecta is unknown. We derive a rigorous analytical solution for the relativistic 90 degree shocks under the ideal MHD…
Early measurements of SN 1987A indicate a beam/jet (BJ) which hit polar ejecta (PE) to produce the "Mystery Spot" (MS). The SN flash takes an extra 8 d to hit the MS, and this was confirmed at 2e39 ergs/s in the optical at day 8. A ramp in…
A growing number of gamma-ray burst (GRB) afterglows is observed at very-high energies (VHE, $\gtrsim 100$ GeV). Yet, our understanding of the mechanism powering the VHE emission remains baffling. We make use of multi-wavelength…
High-redshift gamma-ray bursts (GRBs) provide a powerful tool to probe the early universe, but still for relatively few do we have good observations of the afterglow. We here report the optical and near-infrared observations of the…
The optical afterglow of the gamma-ray burst GRB 970508 (z = 0.835) was a few hundred times more luminous than any supernova. Therefore, a name `hypernova' is proposed for the whole GRB/afterglow event. There is tentative evidence that the…
Gamma-ray bursts (GRBs) are most intense transient gamma-ray events in the sky when they are on together with the strong evidences (i.e. the isotropic and inhomogeneous distribution of GRBs detected by BASTE) that they are located at…
Long duration gamma-ray bursts (GRB) are at cosmological distance, they appear to be located near star forming regions, and are likely associated with some type of supernovae. They are also likely to be strongly beamed, which lowers their…
Progenitor stars of long gamma-ray bursts (GRBs) could be surrounded by a significant and complex nebula structure lying at a parsec scale distance. After the initial release of energy from the GRB jet, the jet will interact with this…
Millisecond pulsars with strong magnetic fields may be formed through several processes, e.g. accretion-induced collapse of magnetized white dwarfs, merger of two neutron stars. During the birth of such a pulsar, an initial fireball…
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…
The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the…
Gamma Ray Bursts as recent GRB990123 and GRB990510 are observed to occur in cosmic volumes with a corresponding output reaching, for isotropic explosions, energies as large as two solar masses annihilation. These energies are underestimated…
Gamma-Ray Bursts (GRBs) are the strongest explosions in the Universe, and are powered by initially ultra-relativistic jets. The angular profile of GRB jets encodes important information about their launching and propagation near the central…
A number of gamma-ray bursts (GRBs) exhibit the late simultaneous bumps in their optical and Xray afterglows around the jet break. Its origin is unclear. Based on the following two facts, we suggest that this feature may sound a transition…
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…