Wednesday

For many years the coalsence of a binary neutron star has been seen as the most promising phenomenon to be detected by both gravitational wave and electromagnetic emission. Such events are also believed to be the progenitors of short gamma-ray bursts (GRBs); however, since the GRB emission is beamed a GRB is only expected to be detected from a narrow range of observing angles, thus the probability of observing a short GRB coincident with a GW event was thought to be low. As it turned out, the first binary neutron star merger detected by Advanced LIGO-Virgo, GW 170817, was accompanied by a short burst of gamma-rays, GRB 170817A, detected by the Fermi-GBM. While superficially a 'short gamma-ray burst', this event does not match the simple models of such phenomena, either in its prompt gamma-ray emission or the later X-ray, optical or radio evolution. In this talk I will review some of the results and analysis of GW 170817 and consider both the questions and challenges this raises for the O3 observing run of Advanced LIGO-Virgo.