TITLE: GCN CIRCULAR NUMBER: 35665 SUBJECT: IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 24/02/04 15:33:21 GMT FROM: Giacomo Sommani at Ruhr-Universität Bochum <gsommani@icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2024-02-04 at 09:09:00.44 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 1.6084 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/138938_62272876.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2024-02-04 Time: 09:09:00.44 RA: 348.40 (+1.10, -1.00 deg 90% PSF containment) J2000 Dec: +10.28 (+0.72, -0.76 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-DR4 or 3FHL catalog sources in the 90% uncertainty region. The nearest gamma-ray source in either catalog is 4FGL J2308.9+1111 at RA: 347.25 deg, Dec: 11.20 deg J2000 (1.46 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/35665. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...