TITLE: GCN CIRCULAR NUMBER: 33065 SUBJECT: IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 22/12/16 10:45:39 GMT FROM: Dr. Massimiliano Lincetto at Ruhr-Universitaet Bochum The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 22-12-16 at 06:00:14.01 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_Bronze alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 1.59 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/137390_43495485.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 22-12-16 Time: 06:00:14.01 UT RA: 6.86 (+1.08/-2.06 deg 90% PSF containment) J2000 Dec: +10.43 (+1.54/-1.07 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 are no Fermi 4FGL or 3FHL catalog sources in the 90% uncertainty region. The nearest gamma-ray source in either catalog is 4FGL J0023.4+0920 at RA 5.85, dec +9.35 J2000, located 1.47 deg away from the best fit 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