A mildly relativistic wide-angle outflow in the neutron star merger GW170817

Understand

GW170817 is the first gravitational wave detection of a binary neutron star merger.

• It was accompanied by radiation across the electromagnetic spectrum and localized to the galaxy NGC 4993 at a distance of 40 Mpc.
• It has been proposed that the observed gamma-ray, X-ray and radio emission is due to an ultra-relativistic jet launched during the merger, directed away from our line of sight.
• The presence of such a jet is predicted from models positing neutron star mergers as the central engines driving short-hard gamma-ray bursts (SGRBs).