TITLE:   GCN CIRCULAR
NUMBER:  34703
SUBJECT: IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
DATE:    23/09/15 18:18:17 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-230914A (https://gcn.nasa.gov/circulars/34693) in a time range of 1000 seconds centered on the alert event time (2023-09-14 05:12:43.710 UTC to 2023-09-14 05:29:23.710 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-230914A. 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-230914A 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 7e+04 GeV. 

A subsequent search was performed including 2 days of data centered on the alert event time (2023-09-13 05:21:03.710 UTC to 2023-09-15 05:21:03.710 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-230914A 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)