Calorimetry of GRB 030329: Simultaneous model fitting to the broadband radio afterglow and the observed image expansion rate

Author: Bob Mesler

Abstract: We performed calorimetry on the burst GRB 030329 by simultaneously fitting the broadband radio afterglow and the observed afterglow image size to a semi-analytic MHD and afterglow emission model. Our semi-analytic method was successfully used to fit archival measurements of the afterglow up to 5.5 years after the burst. Values for the initial burst parameters were determined and the nature of the circumburst medium was explored. Additionally, direct measurements of the lateral expansion rate of the radio afterglow image size allowed us to independently estimate the initial Lorentz factor of the jet.