Low-latency Gravitational-wave Alerts for Multimessenger Astronomy during the Second Advanced LIGO and Virgo Observing Run
B.~P. Abbott, R. Abbott, T.~D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, R.~X. Adhikari, V.~B. Adya, et al
April 2019