TITLE: GCN CIRCULAR NUMBER: 35841 SUBJECT: IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 24/03/01 00:32:04 GMT FROM: Marcos Santander at U of Alabama <jmsantander@ua.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2024-02-29 at 15:48:21.52 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 1.336 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, more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2024-02-29 Time: 15:48:21.52 UT RA: 72.25 (+1.28, -1.26 deg 90% PSF containment) J2000 Dec: +15.79 (+1.08, -0.92 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 known Fermi-LAT source (either in the 4FGL-DR4 or 3FHL catalogs) located within the 90% uncertainty region of the event: 4FGL J0445.7+1535, located at RA: 71.44 deg, Dec: 15.60 deg J2000 (0.81 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/35841. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...