TITLE: GCN CIRCULAR NUMBER: 33117 SUBJECT: IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube DATE: 22/12/28 20:32:18 GMT FROM: Abhishek Desai at ICECUBE/U of Wisconsin 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-221223A (https://gcn.gsfc.nasa.gov/gcn3/33094.gcn3) reported in the prompt GCN Notice in a time range of 1000 seconds centered on the alert event time (2022-12-23 07:34:40.523 UTC to 2022-12-23 07:51:20.523 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-221223A. The IceCube sensitivity to neutrino point sources with an E^-2.0 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-221223A is 4.3e-02 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.0 spectrum have energies in the approximate energy range between 7e+02 GeV and 3.5e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2022-12-22 07:43:00.523 UTC to 2022-12-24 07:43:00.523 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^-2.0 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-221223A is 4.5e-02 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)