TITLE: GCN CIRCULAR NUMBER: 27758 SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 200517A DATE: 20/05/19 16:46:54 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team: MAXI/GSC detected GRB 200517A at 11:27:21 UT (GCN 27750). There was no Fermi-GBM onboard trigger around the event. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no counterparts. The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals identified a transient most significantly on the 8.192 s timescale, with a log likelihood ratio of 13 and a location consistent with the MAXI/GSC event. The GBM targeted search event was found with the highest significance with a "soft" spectrum (Band function with Epeak=70 keV, alpha=-1.9, beta=-3.7) for a GRB. [1] Goldstein et al. 2019 arXiv:1903.12597