Over the past few years, long-duration gamma-ray bursts (GRBs),
including the subclass of X-ray flashes (XRFs), have been revealed to
be a rare variety of Type Ibc supernova (SN Ibc). While all these
events result from the death of massive stars, the electromagnetic
luminosities of GRBs and XRFs exceed those of ordinary Type Ibc SNe by
many orders of magnitude. The observed diversity of stellar death
corresponds to large variations in the energy, velocity, and geometry
of the explosion ejecta. Using multi-wavelength (radio, optical,
X-ray) observations of the nearest GRBs, XRFs, and SNe...