  During the in-spiral stage of a compact binary, a wind bubble could be blown
into interstellar medium, if the electromagnetic radiation due to the binary
orbital motion is strong enough. Therefore, short gamma-ray bursts (SGRBs) due
to double neutron star mergers would in principle happen in a wind bubble
environment, which can influence the propagation of the SGRB jet and the
consequent afterglow emission. By calculating the dynamics and synchrotron
radiation of the jet-driven external shock, we reveal that an abrupt jump could
appear in the afterglow light curves of SGRBs and the observational time of the
jump is dependent on the viewing angle. This light curve jump provides an
observational signature to constrain the radius of the wind bubble and then the
power of the binary electromagnetic radiation, by combining with gravitational
wave detection.
