Observational signature of a wind bubble environment for double neutron star mergers

Abstract

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.

Does a long-lived remnant neutron star exist after short gamma-ray burst GRB 160821B?

“…The observations of GRB 170817A and its afterglows robustly confirmed the long-standing hypothesis that SGRBs can originate from compact binary mergers. Moreover, it became possible to explore the angular structure of the SGRB jet from an off-axis view (Lamb & Kobayashi 2017;Granot et al 2018;Lazzati et al 2018;Mooley et al 2018a,b;Li et al 2019). Meanwhile, the observations of AT 2017gfo indicated the existence of the merger ejecta, which suggests that the progenitor binary should at least contain one NS.…”