A First-principle Simulation of Blast-wave Emergence at the Photosphere of a Neutron Star Merger

Abstract We present the first ab initio simulation of a radiation-mediated shock emerging at photosphere relativistic outflow. The is performed using our code radshock that follows fluid dynamics coupled to time-dependent radiative transfer, calculated with Monte-Carlo method. use examine blast wave from neutron star merger GW170817. It was previously proposed ejected dark, relativistically expanding, homologous envelope, and then an explosion inside envelope produced observed gamma-ray burst GRB 170817A. Our demonstrates how generates radiation as it propagates through approaches its photosphere, releases radiation, collapses, splitting into two collisionless shocks microscopic thickness. find light curve spectral evolution burst; both are similar