GCN Circular 33787

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-Cascade 230511A (https://gcn.gsfc.nasa.gov/notices_amon_icecube_cascade/137930_36941090.amon) in a time range of 1000 seconds centered on the alert event time (2023-05-11 05:37:14.980 UTC to 2023-05-11 05:53:54.980 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 230511A. 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 230511A ranges from 1.3e-01 to 2.6e+00 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+06 GeV. 

A subsequent search was performed including 2 days of data centered on the alert event time (2023-05-10 05:45:34.980 UTC to 2023-05-12 05:45:34.980 UTC). In this case, we report a p-value of 0.03, 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 230511A ranges from 1.5e-01 to 2.5e+00 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)