Related papers: Proto-Magnetars as GRB Central Engines: Uncertaint…
Magnetars are modelled as sources that derive their output from magnetic energy that substantially exceeds their rotational energy. An implication of the recent polarization measurement of GRB 021206 is that the emission mechanism may be…
The existence of a strange quark star (QS) predicted in the Bodmer-Witten hypothesis has been a matter of debate. The combustion from a neutron star to a strange QS in its accreted process in a low-mass X-ray binary is proposed to be a…
While Gamma Ray Bursts (GRBs) have the potential to shed light on the astrophysics of jets, compact objects, and cosmology, a major set back in their use as probes of these phenomena stems from our incomplete knowledge surrounding their…
The remnant of a neutron star binary coalescence is expected to be temporarily stabilised against gravitational collapse by its differential rotation. We explore the possibility of dynamo activity in this remnant and assess the potential…
By considering similar observed properties of gamma ray bursts (GRB) and solar flares with the prevailing physical conditions in the cosmic environment, the following study suggests that most likely and promising energy source for the…
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…
The binary neutron star merger GW170817/GRB170817A confirmed that at least some neutron star mergers are the progenitors of short gamma-ray bursts. Many short gamma-ray bursts have long-term x-ray afterglows that have been interpreted in…
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…
We discuss a model for long Gamma-Ray-Bursts in which the central engine is associated with the conversion process of a metastable hadronic star into a star containing quark matter. We analyze the observational signatures of the model, i.e.…
The prompt emission, X-ray plateau, and X-ray flares of Gamma-ray bursts (GRB) are thought to be from internal dissipation, and the magnetar as the central engine with propeller fallback accretion is proposed to interpret the observed…
The modified version of a bullet model for gamma ray bursts is studied. The central engine of the source produces multiple sub-jets that are contained within a cone. The emission of photons in the source frame of a sub-jet either takes part…
Many gamma-ray bursts are followed by periods of extended emission. At least in some cases, the burst afterglow may be powered by a rapidly rotating, highly-magnetised neutron star, which spins down due to electromagnetic and gravitational…
Extended, fading emissions in multi-wavelength are observed following Gamma-ray bursts (GRBs). Recent broad-band observational campaigns led by the Swift Observatory reveal rich features of these GRB afterglows. Here we review the latest…
A spinar is a quasi-equilibrium collapsing object whose equilibrium is maintained by the balance of centrifugal and gravitational forces and whose evolution is determined by its magnetic field. The spinar quasi equilibrium model recently…
The bright GRB 210610B was discovered simultaneously by Fermi and Swift missions at redshift 1.13. We utilized broadband Fermi-GBM observations to perform a detailed prompt emission spectral analysis and to understand the radiation physics…
We compare the prompt intrinsic spectral properties of a sample of short Gamma--ray Burst (GRB) with the first 0.3 seconds (rest frame) of long GRBs observed by Fermi/GBM. We find that short GRBs and the first part of long GRBs lie on the…
Cusps of superconducting strings can serve as GRB engines. A powerful beamed pulse of electromagnetic radiation from a cusp produces a jet of accelerated particles, whose propagation is terminated by the shock responsible for GRB. A single…
The nature of the central engines of gamma-ray bursts (GRBs) and the composition of their relativistic jets are still under debate. If the jets are Poynting flux dominated rather than baryon dominated, a coherent radio flare from magnetic…
Over half a century from the discovery of gamma-ray bursts (GRBs), the dominant radiation mechanism responsible for their bright and highly variable prompt emission remains poorly understood. Spectral information alone has proven…
We calculate the structure and neutron content of neutrino-heated MHD winds driven from the surface of newly-formed magnetars (``proto-magnetars'') and from the midplane of hyper-accreting disks, two of the possible central engines for…