Related papers: Relativistic shock breakout from a stellar wind
We calculate the observed luminosity and spectrum following the emergence of a relativistic shock wave from a stellar edges. Shock waves propagating at $0.6<\Gamma_\text{sh}\beta_\text{sh}$, where $\Gamma_\text{sh}$ is the shock Lorentz…
The breakout of a fast ($>0.1 c$), yet sub-relativistic shock from a thick stellar wind is expected to produce a pulse of X-rays with a rise time of seconds to hours. Here, we construct a semi-analytic model for the breakout of a…
A large variety of explosions result in mildly or ultra relativistic shock breakouts. Here we calculate the luminosity and spectrum that these breakouts produce. In order to do so we improve an analytic description of relativistic radiation…
Strong explosion of a compact star surrounded by a thick stellar wind drives a fast ($>0.1c$) radiation mediated shock (RMS) that propagates in the wind, and ultimately breaks out gradually once photons start escaping from the shock…
We present Monte Carlo simulations of relativistic radiation-mediated shocks (RRMS) in the photon-starved regime, incorporating photon escape from the upstream region--characterized by the escape fraction, $f_{\rm esc}$--under a…
New two- and three-dimensional calculations are presented of relativistic jet propagation and break out in massive Wolf-Rayet stars. Such jets are thought responsible for gamma-ray bursts. As it erupts, the jet is surrounded by a cocoon of…
We construct models for gamma-ray bursts where the emission comes from internal shocks in a relativistic wind with a highly non uniform distribution of the Lorentz factor. We follow the evolution of the wind using a very simplified approach…
We present time-dependent axisymmetric magnetohydrodynamic simulations of the interaction of a relativistic magnetized wind produced by a proto-magnetar with a surrounding stellar envelope, in the first $\sim 10$ seconds after core…
We present an analysis of the Internal Shock Model of GRBs, where gamma-rays are produced by internal shocks within a relativistic wind. We show that observed GRB characteristics impose stringent constraints on wind and source parameters.…
We have studied the relativistic beamed outflow proposed to occur in the collapsar model of gamma-ray bursts. A jet forms as a consequence of an assumed energy deposition of $\sim 10^{50}- 10^{51}$ erg/s within a $30^{\circ}$ cone around…
It is proposed that the prompt emission observed in bursts that exhibit a thermal component originates from relativistic radiation mediated shocks that form below the photosphere of the GRB outflow. It is argue that such shocks are expected…
The prompt emission of gamma-ray bursts (hereafter GRBs) probably comes from a highly relativistic wind which converts its kinetic energy into radiation via the formation of shocks within the wind itself. Such "internal shocks" can occur if…
We investigate the relativistic breakout of a shock wave from the surface of a star. In this process, each fluid shell is endowed with some kinetic and thermal energy by the shock, and then continues to accelerate adiabatically by…
Sudden collapse of a compact object, or coalescence of a compact binary, can generate an unsteady relativistic wind that lasts for a few seconds. The wind is likely to carry a high magnetic field; and its Lorentz factor depends on the…
We calculate the expected envelope of emission for relativistic shells under the assumption of local spherical symmetry. Gamma-Ray Burst envelopes rarely conform to the expected shape, which is similar to a FRED; a fast rise and exponential…
Wolf-Rayet stars are known to eject winds. Thus, when a Wolf-Rayet star explodes as a supernova, a fast, $>30,000$ km/s, shock is expected to be driven through a wind. We study the signal expected from a fast supernova shock propagating…
It is shown that an ultrarelativistic shock with the Lorentz factor of order of tens or higher propagating in a moderately dense interstellar medium (density above $\sim 1000 $ cm$^{-3}$) undergoes a fast dramatic transformation into a…
The development of instabilities leading to the formation of internal shocks is expected in the relativistic outflows of both gamma-ray bursts and blazars. The shocks heat the expanding ejecta, generate a tangled magnetic field and…
The breakout of a supernova shock wave through the progenitor star's outer envelope is expected to appear as an X-ray flash. However, if the supernova explodes inside an optically-thick wind, the breakout flash is delayed. We present a…
In the neutron-rich internal shocks model for gamma-ray bursts (GRBs), the Lorentz factors (LFs) of ion shells are variable, and so are the LFs of accompanying neutron shells. For slow neutron shells with a typical LF of approximate tens,…