TITLE: GCN CIRCULAR NUMBER: 31120 SUBJECT: IceCube-211123A: Upper limits from Fermi-GBM Observations DATE: 21/11/24 20:42:41 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event IceCube-211123A (GCN 31110), at the event time Fermi-GBM was observing the reported neutrino location at: RA: 265.52 (+3.14 -2.84 deg 90% PSF containment) J2000 Dec: 7.33 (+2.38 -2.48 deg 90% PSF containment) J2000 There was no Fermi-GBM onboard trigger around the event time of the neutrino candidate. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around the neutrino candidate time. From this search, no significant signal was found related to IceCube-211123A. We set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------------- 0.128 s: 4.7 7.9 20. 1.024 s: 1.8 3.0 6.5 8.192 s: 0.47 0.88 1.6 These results are preliminary.