GCN Circular 43151
Subject
IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
Event
Date
2025-12-18T21:55:53Z (3 days ago)
From
A. Zegarelli at Ruhr University Bochum <azegarelli@icecube.wisc.edu>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 25-12-18 at 20:21:00.63 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 0.8234 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/141741_9008919.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 25-12-18
Time: 20:21:00.63 UT
RA: 353.60 (+0.90/-0.74 deg 90% PSF containment) J2000
Dec: 44.15 (+0.46/-0.45 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 Fermi 4FGL-DR4 source in the 90% uncertainty region, i.e., the unassociated gamma-ray source 4FGL J2331.6+4430 at RA: 552.90 deg, Dec: 44.51 deg J2000 (0.62 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