TITLE: GCN CIRCULAR NUMBER: 26622 SUBJECT: IceCube-191231A: Upper limits from Fermi-GBM Observations DATE: 19/12/31 23:05:00 GMT FROM: C. Michelle Hui at MSFC/Fermi-GBM C. M. Hui (MSFC) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event 191231A (GCN 26620), at the event time Fermi-GBM was observing the reported neutrino location at: RA: 46.36 (+4.27 -3.47 deg 90% PSF containment) J2000 Dec: 20.42 (+2.11 -2.80 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-191231A. 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:      6.5     10.      19.  1.024 s:      1.7      2.6      4.5  8.192 s:      0.3      0.6      1.4