AstroNote 2026-219

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

IceCube has performed a search for track-like muon neutrino events arriving from the direction of SN 2026sqf following the report from BHTOM (AstroNote: https://www.wis-tns.org/astronotes/astronote/2026-214), in a time range of six days (2026-07-03 06:01:09.000 UTC to 2026-07-09 06:01:09.000 UTC), during which IceCube was collecting good quality data. The search window extends from five days before to one day after the reported discovery time, 2026-07-08 06:01:09 UTC. The five-day pre-discovery interval accounts for the uncertainty in the explosion and shock-breakout time, while the additional day after discovery includes the earliest follow-up observations. 

We report a p-value of 1.00, consistent with no significant excess track events with respect to the atmospheric background only hypothesis. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E² dN/dE = 7.4e-2 GeV cm^-2 at 90% CL, for an E^-2 power law.
90% of events IceCube would detect from a source at this declination with an E^-2 spectrum are between approximately 600 GeV and 250 TeV. 

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.