  The spatiotemporal coincidence of supernova (SN) 1998bw and gamma-ray burst
(GRB) 980425 and this supernova's unusual optical and radio properties have
prompted many theoretical models that produce GRBs from supernovae. We review
the salient features of our simple, spherical model in which an energetic
supernova explosion shock accelerates a small fraction of the progenitor's
stellar envelope to mildly relativistic velocities. This material carries
sufficient energy to produce a weak GRB and a bright radio supernova through an
external shock against a dense stellar wind.
