  Many short Gamma-Ray Bursts (sGRBs) have a prolonged plateau in the X-ray
afterglow lasting up to tens of thousands of seconds. A central engine
injecting energy into the remnant may fuel the plateau. A simple analytic model
describing the interaction of the magnetized relativistic wind from a
rapidly-rotating magnetar with the surrounding environment can reproduce X-ray
plateaux and instantaneous spectra. The model is analogous to classic,
well-established models of young supernova remnants and applies the underlying
physics to sGRB remnants. The light curve and spectra produced by the model are
compared to observations of GRB 130603B. The spectra are also used to estimate
parameters of the magnetar including its poloidal field strength and angular
frequency. If combined with a gravitational wave signal, this model could
provide insight into multimessenger astronomy and neutron star physics.
