TITLE: GCN CIRCULAR NUMBER: 40296 SUBJECT: IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube DATE: 25/04/30 21:59:47 GMT FROM: Alicia Mand at IceCube/UW-Madison <aemand@wisc.edu> 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-250426A (https://gcn.nasa.gov/circulars/40253) in a time range of 1000 seconds centered on the alert event time (2025-04-26 17:36:38.160 UTC to 2025-04-26 17:53:18.160 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-250426A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250426A is 1.4e-01 GeV cm^-2 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 9e+04 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-04-25 17:44:58.160 UTC to 2025-04-27 17:44:58.160 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250426A is 1.7e-01 GeV cm^-2 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) View this GCN Circular online at https://gcn.nasa.gov/circulars/40296. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...