TITLE: GCN CIRCULAR NUMBER: 32499 SUBJECT: IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube DATE: 22/08/29 14:14:46 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison thwaites@wisc.edu
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search [1] for track-like muon neutrino events arriving from the direction of IceCube-Cascade 220826A (https://gcn.gsfc.nasa.gov/notices_amon_icecube_cascade/136985_60401984.amon) in a time range of 1000 seconds centered on the alert event time (2022-08-26 21:29:53.690 UTC to 2022-08-26 21:46:33.690 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-Cascade 220826A. 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-Cascade 220826A ranges from 1.4e-01 to 1.5e-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 1e+05 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2022-08-25 21:38:13.690 UTC to 2022-08-27 21:38:13.690 UTC). In this case, we report a p-value of 0.02, 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-Cascade 220826A ranges from 1.6e-01 to 1.8e-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.edumailto:roc@icecube.wisc.edu.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)