Accretion-to-jet energy conversion efficiency in GW170817

Gamma-ray bursts (GRBs) are thought to be produced by short-lived, supercritical accretion onto a newborn compact object. Some process is believed tap energy from the object, or disc, powering launch of relativistic jet. For first time, we can construct independent estimates GRB jet and mass in disc its central engine; this thanks gravitational wave observations GW170817 binary neutron star merger Laser Interferometer Gravitational Observatory (LIGO) Virgo interferometers, as well global effort monitor afterglow associated short gamma-ray burst 170817A on long-term, high-cadence, multi-wavelength basis. In work, estimate accretion-to-jet conversion efficiency GW170817, that is, ratio total rest energy, compare quantity with theoretical expectations Blandford-Znajek neutrino-antineutrino annihilation ( νν̄ ) jet-launching mechanisms mergers. Based previously published modelling afterglow, posterior probability density distribution bipolar jets launched remnant. By applying new numerical-relativity-informed fitting formula for mass, remnant mass. Combining two, system, carefully accounting uncertainties. The η ∼ 10 −3 , an uncertainty slightly less than two orders magnitude. This low agreement $ \nu\bar\nu mechanism, which therefore cannot excluded measurement alone. also agrees anticipated provided magnetic field right after predominantly toroidal (which expected result dynamics). combines Future applications method larger number systems will reduce uncertainties reveal whether not it universal. This, turn, provide insights into conditions