TP-11

Hydrodynamics and Radiation from a Relativistic Expanding Jet with applications to GRB afterglow

Jonathan Granot (Racah Institute, Hebrew University, Jerusalem 91904, Israel) Mark Miller (Department of Physics Washington University, St. Louis, MO, USA) Tsvi Piran (Racah Institute, Hebrew University, Jerusalem 91904, Israel) Wai-Mo Suen (Department of Physics Washington University, St. Louis, MO, USA)

We present fully relativistic three dimensional calculations of the slowing down and spreading of a relativistic jet by an external medium like the ISM. Using the hydrodynamic conditions determined by the hydrodynamic calculations and assuming that the electron and Magnetic energy densities are a fixed fraction of the internal energy we calculate the resulting spectra and light curves. We compare our results with the observations of breaks in the afterglow of some recent GRBs.