Videos of GRB simulations
A full short GRB simulation from the jet launch to the afterglow phase
The video depicts the hydrodynamics and evolution of a double NS merger system, similar to that of GW170817. It is based on relativistic hydrodynamical simulations which cover all relevant times, from the time of the jet launch until the observed afterglow emission is turned off. Following a double NS merger, mass is ejected in two forms: non-relativistic massive core ejecta and mildly-relativistic ejecta. The jet (in red), launched shortly after into the ejecta, interacts with it and forms the inner (yellow) and outer (green) cocoon. As soon as the jet-cocoon structure breaks out of the core ejecta into the mildly-relativistic tail ejecta, it accelerates and expands. Once it breaks out of the tail ejecta, first light is emitted via shock breakout. Due to numerical considerations the simulation is converted from 3D to 2D at lab time of 0.8s, which is also when the jet engine is stopped. The outflow then keeps expanding until reaching the homologous phase, in which the structure remains unchanged until its interaction with the ISM at about 500 days begins. The final part of the simulation shows the hydrodynamics of this interaction (right panel), observed afterglow light curve (middle) and observed image at 20deg with the corresponding observer time (left). During the interaction of the outflow with the ISM notable shocks are formed in the outflow. During the first ~100 days (observer time), the light curve and images are dominated by the cocoon emission, after which the jet emission becomes dominant until the light curve fades due to the jet deceleration. The simulation provides a good fit to both the observed light curve and images at a viewing angle of 20deg. The 2D energy density and the four velocity in a jet choked by GW compact binary merger's ejecta
When the jet is choked, its energy is deposited into the cocoon which continues to propagate inside the ejecta until breaking out of it.
Upon breakout, energy is released in gamma-rays. Later it cools adiabatically and emits synchrotron radiation.
We show that this emission agrees very well with the entire EM spectrum of GRB170817A. The energy density and the four velocity in a successful SGRB
This simulation began in 3D as required for collimated successful jet in a dense medium. after
As the jet and the cocoon break out of the ejecta, we map the 3D simulation into 2D. Similarly to the choked jet scenario, both emit gamma-rays upon breakout, and later cool adiabatically and emit synchrotron radiation.
This emission can also be compatible with the EM spectrum of GRB170817A, but not as good as the choked jet scenario. The 3D mass density in a LGRB system
The 3D energy density and the four velocity in a LGRB system
The 3D energy density in a SGRB system The 2D energy density in a SGRB system A 2D simulation which evolves differently from the 3D above, this shows the importance in modeling successful jets in 3D. The 2D mass density in a FGRB system All numerical simulations have been conducted with PLUTO (Mignone et al. 2007).