TITLE: GCN CIRCULAR NUMBER: 31055 SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 211106A DATE: 21/11/08 19:01:41 GMT FROM: Cori Fletcher at USRA <cfletcher@usra.edu> C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team: Swift/BAT-GUANO detected GRB 211106A at 04:37:31.2 UT (GCN 31049). This event was also detected by INTEGRAL/SPI-ACS #9504 and Konus-Wind (GCN 31054). 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 0.256 s timescale, with a location consistent with the Swift/BAT-GUANO event, using the standard search protocol with a S/N of 22. This event was detected ~10 s after GBM exited SAA. The GBM targeted search event was found with the highest significance with a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB. [1] Goldstein et al. 2019 arXiv:1903.12597