1. Department of Physics; Department of Astronomy & Astrophysics; Center for Multimessenger Astrophysics, Institute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USA
2. School of Natural Sciences, Institute for Advanced Study , Princeton, New Jersey 08540, USA
3. Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University , Kyoto, Kyoto 606-8502, Japan
4. Center for Neutrino Physics, Department of Physics , Virginia Tech, Blacksburg, VA 24061, USA
5. Kavli IPMU (WPI), UTIAS, The University of Tokyo , Kashiwa, Chiba 277-8583, Japan