TITLE: GCN CIRCULAR NUMBER: 30871 SUBJECT: IceCube-210922A: Upper limits from Fermi-GBM Observations DATE: 21/09/23 15:47:11 GMT FROM: Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu> C. Malacaria (USRA) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event IceCube-210811A (GCN 30862), at the event time Fermi-GBM was observing the reported neutrino location at: RA: 60.73 (+0.96, -0.66 deg 90% PSF containment) J2000 Dec: -4.18 (+0.42, -0.55 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-210922A. 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 norm hard -------------------------------------- 0.128 s: 6.4 11. 14. 1.024 s: 2.1 3.4 4.6 8.192 s: 0.6 0.9 1.4 These results are preliminary.