sent out an alert with coordinates for the possible source. The detection of gamma rays above 100 MeV by the Fermi-LAT Collaboration and between 100 GeV and 400 GeV by the MAGIC Collaboration from the blazar TXS 0506+056 (reported September 28 and October 4, respectively) was deemed positionally consistent with the neutrino signal. The signals can be explained by ultra-high-energy protons accelerated in blazar jets, producing neutral pions (decaying into gamma rays) and charged pions (decaying into neutrinos). This is the first time that a neutrino detector has been used to locate an object in space and a source of cosmic rays has been identified. October 2019 (announced February 2021): On October 1, a high energy neutrino was detected at IceCube and follow-up measurements in visible light, ultraviolet, x-rays and radio waves identified the tidal disruption event AT2019dsg as possible source. November 2019 (announced June 2022): A second high energy neutrino detected by IceCube associated with a tidal disruption event AT2019fdr. References External links AMON website Astronomy Observational astronomy Astrophysics Astronomical sub-disciplines