TITLE: GCN CIRCULAR NUMBER: 35328 SUBJECT: IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 23/12/12 16:53:19 GMT FROM: Giacomo Sommani at Ruhr-Universität Bochum <gsommani@icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2023-12-11 at 00:47:31.79 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 3.30 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/138669_4054005.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2023-12-11 Time: 00:47:31.79 UT RA: 311.48 (+1.15, -2.33 deg 90% PSF containment) J2000 Dec: +10.28 (+0.67, -0.68 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. Three gamma-ray sources listed in the 4FGL-DR4 Fermi-LAT catalog are located in the 90% uncertainty of the event. The sources are 4FGL J2044.0+1036, 4FGL J2047.3+1051 and 4FGL J2049.9+1002. The three objects are located 0.6, 0.7 and 1.0 deg away from the best-fit position, respectively. 4FGL J2049.9+1002 was observed in a high-emission state between September and November of this year by Fermi LAT: https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source..... 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/35328. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...