TITLE: GCN CIRCULAR NUMBER: 39108 SUBJECT: EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube DATE: 25/01/31 15:15:59 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 for track-like muon neutrino events arriving from the direction of the FBOT EP250108A in a time window of [-600, +5000] seconds from the initial trigger reported by Einstein Probe (GCN 38861), during which time IceCube was collecting good quality data (2025-01-08 12:20:28.34 UTC to 2025-01-08 13:53:48.34 UTC). Zero track-like events are found coincident with the position of the FBOT. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 0.29 GeV cm^-2 at 90% CL, under the assumption of an E^-2 power law. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum have energies in the approximate energy range between 60 TeV and 20 PeV.
A subsequent search was performed with a time window of [-2, +12] days with respect to the initial trigger (2025-01-06 12:30:28.34 UTC to 2025-01-20 12:30:28.34 UTC). In this case, we report a p-value of 1.0, consistent with background expectation. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 0.34 GeV cm^-2 at 90% CL, under the assumption of an E^-2 power law.
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)
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