Related papers: A Narrow Short-Duration GRB Jet from a Wide Centra…
Growing observational evidence supports the proposition that gamma-ray bursts (GRBs) are powered by relativistic jets from massive helium stars whose cores have collapsed to black holes and an accretion disk (collapsars). We model the…
Short Gamma-Ray Bursts (SGRBs) are among the most luminous explosions in the universe, releasing in less than one second the energy emitted by our Galaxy over one year. Despite decades of observations, the nature of their "central-engine"…
Binary neutron-star mergers have long been associated with short-duration gamma-ray bursts (GRBs). This connection was confirmed with the first coincident detection of gravitational waves together with electromagnetic radiation from…
Strong variability is a common characteristic of the prompt emission of gamma-ray bursts (GRB). This observed variability is widely attributed to an intermittency of the central engine, through formation of strong internal shocks in the…
Broadband emission from relativistic outflows (jets) of active galactic nuclei (AGN) and gamma-ray bursts (GRBs) contains valuable information about the nature of the jet itself, and about the central engine which launches it. Using special…
Relativistic jets launched in binary neutron star (BNS) mergers are widely accepted as the engines powering most of the population of short gamma-ray bursts (GRBs). Understanding their structure and dynamics-particularly during and after…
We present the first general relativistic hydrodynamic models of the launch and evolution of relativistic jets and winds, driven by thermal energy deposition, possibly due to neutrino-antineutrino annihilation, in the close vicinity of…
Recent observations suggest that gamma ray bursts (GRBs) and their afterglows are produced in star formation regions in distant galaxies by highly relativistic jets that happen to point in our direction. Relativistic beaming collimates the…
The collapsar model explains the association of long duration gamma-Ray Bursts (GRBs) with stellar collapse. It involves a relativistic jet that forms at the core of a collapsing massive star. The jet penetrates the stellar envelope and the…
Short gamma-ray bursts (sGRBs) are thought to be produced by binary NS mergers. While a sGRB requires a relativistic jet to break out of ejecta, the jet may be choked and fails to produce a successful sGRB. We propose a "delayed breakout"…
GW170817/GRB170817A has offered unprecedented insight into binary neutron star post-merger systems. Its Prompt and afterglow emission imply the presence of a tightly collimated relativistic jet with a smooth transverse structure. However,…
We use relativistic hydrodynamic numerical calculations to study the interaction between a jet and a homologous outflow produced dynamically during binary neutron star mergers. We quantify how the thermal energy supplied by the jet to the…
We examine the propagation of 2-dimensional relativistic jets through the stellar progenitor in the collapsar model for gamma-ray bursts. In agreement with previous studies, we find that relativistic jets are collimated by their passage…
GW170817 and GRB 170817A provided direct evidence that binary neutron star (NSNS) mergers can produce short gamma-ray bursts (sGRBs). However, questions remain about the nature of the central engine. Depending on the mass, the remnant from…
We investigate the dependence of the GRB jet structure and its evolution on the properties of the accreting torus in the central engine. Our models numerically evolve the accretion disk around a Kerr black hole using 3D general relativistic…
Short GRBs are produced by relativistic jets arising from binary NS-NS or NS-BH mergers. Since the detection of the first unambiguous off-axis GRB 170817A, we learned that energy distribution in the jet plays an important role in explaining…
Black holes generate collimated, relativistic jets which have been observed in gamma-ray bursts (GRBs), microquasars, and at the center of some galaxies (active galactic nuclei; AGN). How jet physics scales from stellar black holes in GRBs…
Leading models for the "central engine" of long, soft gamma-ray bursts (GRBs) are briefly reviewed with emphasis on the collapsar model. Growing evidence supports the hypothesis that GRBs are a supernova-like phenomenon occurring in star…
In this study, we investigate the gravitational collapses of rotating stellar systems accounting for Gamma-Ray Burst jet progenitors. Based on the virial theorem of hadron collisional relaxations and Newtonian slow-rotating approximation,…
We consider the gamma ray burst (GRB) central engine that is powered by the collapse of a massive rotating star or compact binary merger. The engine is a hot and dense accretion disk, which is composed of free nucleons, electron-positron…