Multi-scale Modeling of Gamma-ray Bursts*

We present the latest results of a multi-code, multi-scale effort to model the most luminous explosions in the universe - gamma-ray bursts (GRBs).  We present a model of massive stars collapsing in an interacting binary system and show how such a progenitor can account for not only many of the intrinsic properties of GRBs but also the evolution of the systems’ properties with cosmic redshift.  We also present results on novel techniques for modeling the plasma physics of the relativistic GRB jet, extending first principles kinetic simulations to unprecedented length and time scales.