GCN Circular 31055
Subject
Fermi GBM Sub-Threshold Detection of GRB 211106A
Event
Date
2021-11-08T19:01:41Z (4 years ago)
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