Simulating Dynamical Ejecta Effects On High Energy Emission From Neutron Star and Black Hole Collisions

The main goal of this proposal is to shed light on the processes that give rise to electromagnetic radiation (i.e. a short GRB and a kilonova) that may originate from BNS and NS-BH merger environments. The proposer will use a parameterized model of dynamical ejecta, inspired by numerical relativity simulations of binary neutron star mergers, implemented in GRMHD simulations with the goal of bracketing the effects that the ejecta have on observables. The goal is to develop a jet model which can then lead prediction of long term emission such as Fermi-LAT gamma-rays. As a second step, the results of numerical relativity simulations of binary neutron star mergers will be used as initial conditions for a selected number of GRMHD simulations, in order to simulate the merger and its aftermath in its entirety. The proposal plans to determine the impact of the dynamical ejecta on parameters relevant to the GRB emission, such as jet opening angles, isotropic equivalent luminosities, engine variability and durations of GRBs.