%0 Journal Article
%T The Broadband Afterglow of GRB980329
%A S. A. Yost
%A D. A. Frail
%A F. A. Harrison
%A R. Sari
%A D. Reichart
%A J. S. Bloom
%A S. R. Kulkarni
%A G. H. Moriarty-Schieven
%A S. G. Djorgovski
%A P. A. Price
%A R. W. Goodrich
%A J. E. Larkin
%A F. Walter
%A D. S. Shepherd
%A D. W. Fox
%A G. B. Taylor
%A E. Berger
%A T. J. Galama
%J Physics
%D 2002
%I arXiv
%R 10.1086/342175
%X We present radio observations of the afterglow of the bright gamma-ray burst GRB980329 made between one month and several years after the burst, a re-analysis of previously published submillimeter data, and late-time optical and near-infrared (NIR) observations of the host galaxy. From the absence of a spectral break in the optical/NIR colors of the host galaxy, we exclude the earlier suggestion that GRB980329 lies at a redshift of z >~5. We combine our data with the numerous multi-wavelength observations of the early afterglow, fit a comprehensive afterglow model to the entire broadband dataset, and derive fundamental physical parameters of the blast-wave and its host environment. Models for which the ejecta expand isotropically require both a high circumburst density and extreme radiative losses from the shock. No low density model (n << 10 cm^{-3}) fits the data. A burst with a total energy of ~ 10^{51} erg, with the ejecta narrowly collimated to an opening angle of a few degrees, driven into a surrounding medium with density ~ 20 cm^{-3}, provides a satisfactory fit to the lightcurves over a range of redshifts.
%U http://arxiv.org/abs/astro-ph/0204141v2