IceCube-251225A
GCN Circular 43242
Subject
IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
Date
2025-12-27T03:54:10Z (6 hours ago)
From
Yuhua Yao at IceCube/UW-Madison <yyao255@icecube.wisc.edu>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-251225A (https://gcn.nasa.gov/circulars/43239) in a time range of 1000 seconds centered on the alert event time (2025-12-25 20:05:46.800 UTC to 2025-12-25 20:22:26.800 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-251225A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.4e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251225A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 8e+04 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2025-12-24 20:14:06.800 UTC to 2025-12-26 20:14:06.800 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.7e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251225A in a 2 day
time window.
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.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)
GCN Circular 43239
Subject
IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2025-12-25T22:27:35Z (a day ago)
From
Giacomo Sommani at Ruhr-Universität Bochum <gsommani@icecube.wisc.edu>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 25-12-25 at 20:14:06.80 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 1.0705 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/141764_19814286.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 25-12-25
Time: 20:14:06.80 UT
RA: 297.42 (+0.54/-0.49 deg 90% PSF containment) J2000
Dec: 22.47 (+0.46/-0.48 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