IceCube-211216A: Upper limits from Fermi-GBM Observations

For the IceCube high-energy neutrino candidate event IceCube-211216A (GCN 31241), at the event time Fermi-GBM was observing the reported neutrino location at: RA: 316.05 (+2.58/-1.95 deg 90% PSF containment) J2000 Dec: 15.79 (+1.29/-1.63 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-211216A. 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: 7.9 14. 23. 1.024 s: 2.1 4.1 9.3 8.192 s: 0.6 1.2 2.3 These results are preliminary.