Related papers: On the Composition of GRBs' Collapsar Jets
We numerically analyze the evolution of a long-duration gamma-ray burst jet as it leaves the progenitor star and propagates to the photospheric radius, where radiation can be released. We find that the interaction of the relativistic…
Long-duration gamma-ray bursts (lGRBs) originate in relativistic collimated outflows -- jets -- that drill their way out of collapsing massive stars. Accurately modeling this process requires realistic stellar profiles for the jets to…
We present a suite of the first 3D GRMHD collapsar simulations, which extend from the self-consistent jet launching by an accreting Kerr black hole (BH) to the breakout from the star. We identify three types of outflows, depending on the…
In order to investigate formation of relativistic jets at the center of a progenitor of a long gamma-ray burst (GRB), we develop a two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. We show the code passes many,…
Radially inhomogeneous gamma-ray burst (GRB) jets release variable photospheric emission and can have internal shocks occurring above the photosphere. We generically formulate a photospheric emission model of GRBs including Compton…
In this study, the light curves and spectrum of the photospheric thermal radiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated using 2D relativistic hydrodynamic simulations of jets from a collapsar. As the jet…
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…
Collapsing stars constitute the main black hole (BH) formation channel, and are occasionally associated with the launch of relativistic jets that power $ \gamma $-ray bursts (GRBs). Thus, collapsars offer an opportunity to infer the natal…
A structured gamma-ray burst jet could explain the dimness of the prompt emission observed from GRB$\,170817$A but the exact form of this structure is still ambiguous. However, with the promise of future joint gravitational wave and…
With this paper we introduce the concept of apparent structure of a GRB jet, as opposed to its intrinsic structure. The latter is customarily defined specifying the functions epsilon(theta) (the energy emitted per jet unit solid angle) and…
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…
Gamma-ray bursts (GRBs) are luminous stellar explosions characterized by the ejection of relativistic jets. This work proposes a novel paradigm to study these GRB jets. By analyzing the timing information of prompt pulses and X-ray flares,…
The binary neutron star (BNS) merger event GW170817 clearly shows that a BNS merger launches a short Gamma-Ray Burst (sGRB) jet. Unlike collapsars, where the ambient medium is static, in BNS mergers the jet propagates through the merger…
We present 2D high-resolution hydrodynamic simulations of the relativistic outflows of long-duration gamma-ray burst progenitors. We analyze the properties of the outflows at wide off-axis angles, produced by the expansion of the hot cocoon…
We consider the time-dependent evolution of a relativistic jet following its breakout through the surface of a massive compact star, as envisaged in the collapsar model of gamma-ray bursts. At breakout, the jet is tightly collimated by the…
Long gamma-ray bursts (GRBs) are commonly accepted to originate in the explosion of particularly massive stars, which gives rise to a highly relativistic jet. Internal inhomogeneities in the expanding flow give rise to internal shock waves…
I review aspects of the theory of long-duration gamma-ray burst (GRB) central engines. I focus on the requirements of any model; these include the angular momentum of the progenitor, the power, Lorentz factor, asymmetry, and duration of the…
Gamma-ray bursts are flashes of high-energy radiation lasting from a fraction of a second to several hours. Military satellites made the first detections of GRBs in the late 1960s. The $\gamma$-ray emission forms from shocks in a…
Using a novel approach, the distribution of fluences of long gamma ray bursts derived from the Swift-BAT catalog, was reproduced by a jet-model characterized by the distribution of the total radiated energy in $\gamma$-rays and the…
Long duration gamma-ray bursts (GRBs) are thought to be produced by the core-collapse of a rapidly-rotating massive star. This event generates a highly relativistic jet and prompt gamma-ray and X-ray emission arises from internal shocks in…