Plerion model of the X-ray plateau in short gamma-ray bursts

Abstract

Many short gamma-ray bursts (sGRBs) exhibit a prolonged plateau in the X-ray light curve following the main burst. It is shown that an X-ray plateau at the observed luminosity emerges naturally from a plerion-like model of the sGRB remnant, in which the magnetized, relativistic wind of a millisecond magnetar injects shock-accelerated electrons into a cavity confined by the sGRB blast wave. A geometry-dependent fraction of the plerionic radiation is also intercepted and reprocessed by the optically thick merger ejecta. The relative contributions of the plerion and ejecta to the composite X-ray light curve are estimated approximately with the aid of established ejecta models. The plerionic com..