TITLE: GCN CIRCULAR NUMBER: 35332 SUBJECT: IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube DATE: 23/12/13 22:08:40 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 additional track-like muon neutrino events arriving from the direction of IceCube-231211A (https://gcn.nasa.gov/circulars/35328) in a time range of 1000 seconds centered on the alert event time (2023-12-11 00:39:11.790 UTC to 2023-12-11 00:55:51.790 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-231211A. 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-231211A is 1.3e-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 (2023-12-10 00:47:31.790 UTC to 2023-12-12 00:47:31.790 UTC). One track-like event is found to be within the 90% contour of the alert event. Its properties are shown in the table below. 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-231211A is 1.5e-01 GeV cm^-2 in a 2 day time window. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) ----------------------------------------------------------------------------------------------- 64664 311.73 10.06 1.03 where: dt = Time of track event minus time of alert event (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area 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/35332. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...