TITLE: GCN CIRCULAR NUMBER: 25308 SUBJECT: HAWC-190806A: Upper limits from Fermi-GBM Observations DATE: 19/08/09 20:14:57 GMT FROM: Joshua Wood at MSFC/Fermi-GBM J. Wood (NASA/MSFC) and S. Poolakkil (UAH) report on behalf of the Fermi GBM Team: For HAWC-190806A, Fermi-GBM was observing the full localization region at event time. There was no Fermi-GBM onboard trigger around the event time of HAWC-190806A (GCN 25284). 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 trigger time, and also identified no counterpart candidates. We therefore 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: 2.4 4.8 14. 1.024 s: 0.9 1.5 4.6 8.192 s: 0.4 0.7 1.7