TITLE:   GCN CIRCULAR
NUMBER:  37326
SUBJECT: GRB 240825A: Upper limits from a neutrino search with IceCube
DATE:    24/08/28 20:37:55 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 GRB 240825A (GCN Circular 37274 (Swift);  37301 (Fermi-GBM)). The search was performed at the position of the candidate optical counterpart reported by Swift-UVOT in a time range of -1 hour/+2 hours from the initial trigger reported by Swift-BAT (T0=2024-08-25 15:52:59 UTC) during which IceCube was collecting good quality data. 

Zero track-like events are found to be coincident with the position of the GRB. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 2.8 x 10^-2 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 1 TeV and 5 PeV.

A subsequent search was performed including 2 days of data centered on the Swift-BAT trigger (2024-08-24 15:52:59 UTC to 2024-08-26 15:52:59 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 = 3.0 x 10^-2 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)