GCN Circular 42701

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-Cascade 251112A (https://gcn.gsfc.nasa.gov/notices_amon_icecube_cascade/141589_6342606.amon) in a time range of 1000 seconds centered on the alert event time (2025-11-12 16:25:42.310 UTC to 2025-11-12 16:42:22.310 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, 3 track-like events are found within the 90% containment region of IceCube-Cascade 251112A. We find that these additional 3 events are well described by atmospheric background expectations, with a p-value of 0.97.  IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 1.3e-01 to 2.4e+01 GeV cm^-2 within the 90% spatial containment region of IceCube-Cascade 251112A 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 4e+06 GeV.

A subsequent search was performed including 2 days of data centered on the alert event time (2025-11-11 16:34:02.310 UTC to 2025-11-13 16:34:02.310 UTC). In this case, we report a p-value of 0.21, 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, ranges from 1.5e-01 to 2.5e+01 GeV cm^-2 within the 90% spatial containment region of IceCube-Cascade 251112A 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)