TITLE: GCN CIRCULAR NUMBER: 35485 SUBJECT: IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 24/01/05 15:22:16 GMT FROM: Erik Blaufuss at University of Maryland, College Park <blaufuss@umd.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2024-01-05 at 12:27:42.57 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 2.64 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/138821_46175426.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2024-01-05 Time: 12:27:42.57 UT RA: 72.69 (+0.53, -0.33 deg 90% PSF containment) J2000 Dec: +11.42 (+0.20, -0.08 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. One gamma-ray source listed in the 4FGL-DR4 Fermi-LAT catalog is located in the 90% uncertainty of the event. The source is 4FGL J0449.1+112 (associated with PKS 0446+11), located at RA = 72.28 deg and Dec = +11.36 deg (J2000), 0.4 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/35485. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...