 Solution

The short gamma-ray burst GRB 170817A followed the merger signal by about $1.7\mathrm{s}$, providing direct evidence that at least some short gamma-ray bursts arise from neutron star mergers. The association connects their high-energy emission and relativistic outflows to compact-binary coalescence. It does not establish that every short burst has this progenitor, nor that the observed gamma-ray luminosity is independent of viewing angle.^[ref]