Electromagnetic evidence that SSS17a is the result of a binary neutron star merger. - Kilpatrick CD; Foley RJ; Kasen D; Murguia-Berthier A; Ramirez-Ruiz E; Coulter DA; Drout MR; Piro AL; Shappee BJ; Boutsia K; Contreras C; Di Mille F; et al. (Science (New York, N.Y.), 2017)