Related papers: Solving the missing GRB neutrino and GRB-SN puzzle…
There are about 2000 gamma ray burst (GRB) events known to us with data pouring in at the rate of one per day. While the afterglows of GRBs in radio, optical and X-ray bands are successfully explained by the fireball model, a significant…
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 supranova model for gamma-ray bursts (GRBs) has recently gained popularity. In this scenario the GRB occurs weeks to years after a supernova explosion, and is located inside a pulsar wind bubble (PWB). High energy protons from the PWB…
The progenitors of gamma-ray bursts (GRBs) have long been an unresolved issue. GRB 230307A stands out as an exceptionally bright event, belonging to the long-duration GRBs but also exhibiting a late emission component reminiscent of a…
The observations suggest that $\gamma$-ray bursts (GRBs) are produced by jets of relativistic cannonballs (CBs), emitted in supernova (SN) explosions. The CBs, reheated by their collision with the SN shell, emit radiation and Doppler-boost…
Although the observed spectra for gamma-ray burst (GRB) prompt emission is well constrained, the underlying radiation mechanism is still not very well understood. We explore photospheric emission in GRB jets by modelling the Comptonization…
We report on optical, near-infrared and centimeter radio observations of GRB000418 which allow us to follow the evolution of the afterglow from 2 to 200 days after the gamma-ray burst. In modeling these broad-band data, we find that an…
A rapidly spinning, strongly magnetized neutron star is invoked as the central engine for some Gamma-ray bursts (GRBs), especially, the $"$internal plateau$"$ feature of X-ray afterglow. However, for these $"$internal plateau$"$ GRBs, how…
We investigate a "hypernova" model for gamma-ray bursts (GRBs), i.e., massive C+O star model with relativistic jets. In this model, non-thermal precursors can be produced by the "first" relativistic shell ejected from the star. Main GRBs…
The sources responsible for the emission of high-energy ($\gtrsim$ 100 TeV) neutrinos detected by IceCube are still unknown. Among the possible candidates, active galactic nuclei with relativistic jets are often examined, since the…
GRB 190829A is the fourth closest gamma-ray burst (GRB) to date ($z=0.0785$). Owing to its wide range of radio, optical, X-ray, and the very-high-energy (VHE) observations by H.E.S.S., it has become an essential new source examined by…
Long duration Gamma-Ray Bursts (GRBs) originate from the core collapse of massive stars, but the identity of the central engine remains elusive. Previous work has shown that rapidly spinning, strongly magnetized proto-neutron stars…
The hypothesis that ultra-high energy (>~ 10^19 eV) cosmic rays (UHECRs) are accelerated by gamma-ray burst (GRB) blast waves is assumed to be correct. Implications of this assumption are then derived for the external shock model of…
The detection of a high-energy neutrino from the flaring blazar TXS 0506+056 and the subsequent discovery of a neutrino excess from the same direction have strengthened the hypothesis that blazars are cosmic neutrino sources. The lack,…
We consider GRBs that occur inside pulsar wind bubbles (PWBs), in the context of the supranova model, where initially a supernova explosion takes place, leaving behind a supra-massive neutron star (SMNS), which eventually loses its…
We discuss the fluxes of high energy neutrinos and gamma-rays expected from AGNs if hadrons can be effectively accelerated to ultra-high energies by their relativistic jets, as currently believed. Fluxes of multi-TeV neutrinos detectable by…
Follow-up observations of neutrino events have been a promising method for identifying sources of very-high-energy cosmic rays. Neutrinos are unambiguous tracers of hadronic interactions and cosmic rays. On June 15, 2020, IceCube detected a…
A scenario is proposed that explains both the observed high pulsar velocities and extragalactic gamma-ray bursts (GRBs). The model involves an ultra- relativistic jet from a supernova (SN), that produces a GRB and its afterglow, whose…
Whether gamma-ray bursts are highly beamed or not is a very important question, since it has been pointed out that the beaming will lead to a sharp break in the afterglow light curves during the ultra-relativistic phase, with the breaking…
The source of Ultra High Energy Cosmic Rays (UHECR) is still an unresolved mystery. Up until recently, sources of Gamma Ray Bursts (GRBs) had been considered as a suitable source for UHECR. Within the fireball model, the UHECR produced at…