Multiwavelength follow-up of a rare IceCube neutrino multiplet (2017)
AuthorsAartsen MG, Ackermann M, Adams J, Aguilar JA, Ahlers M, Ahrens M, Al Samarai I, Altmann D, Andeen K, Anderson T, Ansseau I, Anton G, Archinger M, Argüelles C, Auffenberg J, Axani S, Bai X, Barwick SW, Baum V, Bay R, Beatty JJ, Tjus JB, Becker KH, Benzvi S, Berley D, Bernardini E, Bernhard A, Besson DZ, Binder G, Bindig D, Blaufuss E, Blot S, Bohm C, Börner M, Bos F, Bose D, Böser S, Botner O, Braun J, Brayeur L, Bretz HP, Bron S, Burgman A, Carver T, Casier M, Cheung E, Chirkin D, Christov A, Clark K, Classen L, Coenders S, Collin GH, Conrad JM, Cowen DF, Cross R, Day M, De André JPAM, De Clercq C, Del Pino Rosendo E, Dembinski H, De Ridder S, Desiati P, De Vries KD, De Wasseige G, De With M, Deyoung T, Di Lorenzo V, Dujmovic H, Dumm JP, Dunkman M, Eberhardt B, Ehrhardt T, Eichmann B, Eller P, Euler S, Evenson PA, Fahey S, Fazely AR, Feintzeig J, Felde J, Filimonov K, Finley C, Flis S, Fösig CC, Franckowiak A, Friedman E, Fuchs T, Gaisser TK, Gallagher J, Gerhardt L, Ghorbani K, Giang W, Gladstone L, Glauch T, Glüsenkamp T, Goldschmidt Ashow all
On February 17, 2016, the IceCube real-time neutrino search identified, for the first time, three muon neutrino candidates arriving within 100 s of one another, consistent with coming from the same point in the sky. Such a triplet is expected once every 13.7 years as a random coincidence of background events. However, considering the lifetime of the follow-up program the probability of detecting at least one triplet from atmospheric background is 32%. Follow-up observatories were notified in order to search for an electromagnetic counterpart. Observations were obtained by Swift's X-ray telescope, by ASAS-SN, LCO and MASTER at optical wavelengths, and by VERITAS in the very-high-energy gamma-ray regime. Moreover, the Swift BAT serendipitously observed the location 100 s after the first neutrino was detected, and data from the Fermi LAT and HAWC observatory were analyzed. We present details of the neutrino triplet and the follow-up observations. No likely electromagnetic counterpart was detected, and we discuss the implications of these constraints on candidate neutrino sources such as gamma-ray bursts, core-collapse supernovae and active galactic nucleus flares. This study illustrates the potential of and challenges for future follow-up campaigns.