GCN Circular 45462
Subject
IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
Event
Date
2026-08-29T06:13:33Z (5 days ago)
From
Sam Hori at IceCube/U Wisc-Madison <sahori@wisc.edu>
Via
email
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-260825A (https://gcn.nasa.gov/circulars/45438) in a time range of 1000 seconds centered on the alert event time (2026-08-25 10:45:13.633 UTC to 2026-08-25 11:01:53.633 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-260825A. 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 1.5e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260825A 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 5e+04 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2026-08-24 10:53:33.633 UTC to 2026-08-26 10:53:33.633 UTC). In this case, we report a p-value of 0.03, 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 1.8e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260825A 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)