  Excess reddened optical emission has been measured in the power-law decay
afterglow light curves of several GRBs some tens of days after the GRB events.
This emission is claimed to be a signature of a supernova (SN) taking place at
the same time as the GRB event, in support of the collapsar scenario.
Observations of features in prompt and afterglow X-ray spectra of GRBs require
high density, high metallicity material near GRB sources, supporting the
supranova (SA) scenario. These conflicting lines of evidence are resolved in
likely regimes of parameter space if the supernova remnant (SNR) shell is
illuminated and heated by a pulsar wind (PW), and cools following the GRB
event. The heating of the SNR shell by the PW is parameterized, and simplified
expressions for the synchrotron, synchrotron self-Compton, and thermal
radiation fields within the SNR shell and pulsar wind bubble are derived for
monoenergetic injection of wind electrons. A cooling SNR shell could produce
the excess emission detected from GRB 970228, GRB 980326, and GRB 011121. X-ray
synchrotron radiation from the PW electrons provides an important source of
ionizing radiation.
