tokens: We thank Ora Zackay, Zeljko Ivesic, Robert Lupton, and Assaf Horesh for many discussions. This paper is based on observations obtained with the Samuel Oschin Telescope as part of the Palomar Transient Factory project, a scientific collaboration between the California Institute of Technology, Columbia University, Las Cumbres Observatory, the Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford, and the Weizmann Institute of Science. B.Z. is grateful for receiving the Clore fellowship. E.O.O. is incumbent of the Arye Dissentshik career development chair and is grateful for support by grants from the Willner Family Leadership Institute Ilan Gluzman (Secaucus NJ), Israel Science Foundation, Minerva, Weizmann-UK, and the I-Core program by the Israeli Committee for Planning and Budgeting and the Israel Science Foundation (ISF). A.G. acknowledges support from the I-Core program “The Quantum universe,” as well as from the Kimmel Award.
ner_tags: O O B-Person I-Person B-Person I-Person B-Person I-Person O B-Person I-Person O O O O O O O O O O O O B-Telescope I-Telescope I-Telescope O O O O B-Telescope I-Telescope I-Telescope O O O O O O B-Organization I-Organization I-Organization I-Organization B-Organization I-Organization B-Observatory I-Observatory I-Observatory O B-Organization I-Organization I-Organization I-Organization O B-ComputingFacility I-ComputingFacility I-ComputingFacility I-ComputingFacility I-ComputingFacility I-ComputingFacility O B-Organization I-Organization I-Organization O O B-Organization I-Organization I-Organization I-Organization B-Person O O O O O B-Fellowship I-Fellowship B-Person O O O O B-Organization I-Organization I-Organization I-Organization I-Organization O O O O O O O O O B-Organization I-Organization I-Organization I-Organization I-Organization I-Organization B-Location I-Location B-Organization I-Organization I-Organization B-Organization B-Organization O O B-Grant I-Grant O O B-Organization I-Organization I-Organization I-Organization I-Organization I-Organization O O B-Organization I-Organization I-Organization B-Organization B-Person O O O O B-Grant I-Grant I-Grant I-Grant I-Grant O O O O O B-Grant I-Grant