Cannonball model diagnosis of the short gamma ray burst 170817A

The rich and complex data obtained from multi-wavelength observations of SHB170817A, the short hard gamma ray burst (SHB) associated with GW170817 --the first neutron stars merger (NSM) event detected in gravitational waves (GWs)-- are analyzed in the framework of the cannonball model of SHBs. In this model a highly relativistic jet is launched by the nascent massive neutron star (or black hole) into a surrounding glory (light fireball) which was present already before the merger. The SHB was produced by inverse Compton scattering of glory photons by the jet, which was viewed far off-axis. The fading fireball, which produced the initial UVOIR afterglow, was powered by a nascent massive neutron star remnant rather than by a black hole. It was overtaken by a late time X-ray, UVOIR and radio afterglow produced by synchrotron radiation from the decelerating jet in the interstellar medium of the host galaxy. If the radio afterglow of SHB170817A was indeed produced by the jet, it should display a superluminal motion relative to the SHB location, still detectable in VLA and VLBI radio observations.