TITLE: GCN CIRCULAR NUMBER: 33122 SUBJECT: IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 22/12/29 15:01:36 GMT FROM: Dr. Massimiliano Lincetto at Ruhr-Universitaet Bochum The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2022-12-29 at 07:25:27.88 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 average astrophysical neutrino purity for Gold alerts is 50%. This alert has an estimated false alarm rate of 1.014 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/137487_35344578.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2022-12-29 Time: 07:25:27.88 UT RA: 31.90 (+1.68/-1.55 deg 90% PSF containment) J2000 Dec: +4.18 (+1.39/-0.84 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 of the event. The nearest gamma-ray source in either catalog is 4FGL J0215.9+0521 (TXS 0213+051) at RA: 33.99 deg, Dec: 5.35 deg J2000 (2.39 deg away 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