TITLE: GCN CIRCULAR NUMBER: 39132 SUBJECT: IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/02/03 15:40:47 GMT FROM: A. Zegarelli at Ruhr University Bochum azegarelli@icecube.wisc.edu

The IceCube Collaboration (http://icecube.wisc.edu/) reports:

On 2025-02-03 03:59:29.20 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 3.7051 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/140436_11917698.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2025-02-03 Time: 03:59:29.20 UT RA: 253.30 (+0.49, -0.49 deg 90% PSF containment) J2000 Dec: -1.31 (+0.48, -0.44 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.

No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event.

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/39132. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...