The Role of Neutrinos in the Multi-Messenger Picture of Binary Neutron Star Mergers

On August 17 the LIGO/Virgo gravitational wave observatories detected the first binary neutron star merger event (GW170817), a discovery followed by the most ambitious electromagnetic (EM) follow-up campaign ever conducted. Within 2 seconds of the merger, a weak burst of gamma-rays was discovered by the Fermi and INTEGRAL satellites. Within 11 hours, a bright but rapidly-fading thermal optical counterpart was discovered in the galaxy NGC 4993 at a distance of only 130 Million light years. The properties of the optical transient match remarkably well predictions for "kilonova" emission powered by the radioactive decay of heavy nuclei synthesized in the expanding merger ejecta by rapid neutron capture nucleosynthesis (r-process). The rapid spectral evolution of the kilonova emission to near-infrared wavelengths demonstrates that a portion of the ejecta contains heavy lanthanide nuclei. I will describe efforts to create a unified scenario for the range of EM counterparts from GW170817 and their implications for the astrophysical origin of the r-process and the properties of neutron stars. I will focus on the crucial role played by neutrinos in shaping the signals from this event, particularly the color of the kilonova emission. I will also address prospects for detecting ultra-high energy neutrinos from future mergers, particularly in cases where the merger remnant survives as a long-lived magnetized neutron star before collapsing into a black hole