TITLE: GCN CIRCULAR NUMBER: 31195 SUBJECT: IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube DATE: 21/12/10 02:37:44 GMT FROM: Marcos Santander at U. Alabama/IceCube 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-211208A (https://gcn.gsfc.nasa.gov/gcn3/31191.gcn3) in a time range of 1000 seconds centered on the alert event time (2021-12-08 19:54:31.100 UTC to 2021-12-08 20:11:11.100 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-211208A. 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-211208A 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 1e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2021-12-07 20:02:51.100 UTC to 2021-12-09 20:02:51.100 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-211208A is 1.6e-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)