TITLE: GCN CIRCULAR NUMBER: 28887 SUBJECT: IceCube-201114A - IceCube observation of a high-energy neutrino candidate event DATE: 20/11/14 20:00:42 GMT FROM: Erik Blaufuss at U. Maryland/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 20/11/14 at 15:05:31.96 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_GOLD alert stream. The threshold astrophysical neutrino purity for Gold alerts is 50% . This alert has an estimated false alarm rate of 0.92 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/134698_40735501.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 20/11/14 Time: 15:05:31.96 UT RA: 105.25 (+ 1.28 - 1.12 deg 90% PSF containment) J2000 Dec: 6.05 (+ 0.95 - 0.95 deg 90% PSF containment) J2000 We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. There is one Fermi 4FGL/3FHL source located within the 90% localization region, 4FGL J0658.6+0636, located at RA: 104.64 deg, Dec: 6.60 deg (J2000), at a distance of 0.81 deg from the best-fit event position. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu