TITLE:   GCN CIRCULAR
NUMBER:  43713
SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 260211A
DATE:    26/02/12 14:47:00 GMT
FROM:    rhamburg@usra.edu

R. Hamburg (USRA) reports on behalf of the Fermi-GBM Team:

SVOM/ECLAIRs detected GRB 260211A on 2026-02-11 at 19:24:33 UTC (GCN 43705). There was no Fermi-GBM onboard trigger around this time. An automated, blind search for gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no candidates. 

The GBM Targeted Search [1], the most sensitive coherent search for GRB-like signals in GBM, identified a transient starting 0.8 seconds after the ECLAIRs trigger time, most significantly on the 16 s timescale and with a false alarm rate of 4.3e-05 Hz. The Fermi-MET of this transient is 792530678.844 s. The Targeted Search localization is consistent with the ECLAIRs location.
 
Additionally, the GBM Targeted Search transient was found with highest significance using a soft spectral template (i.e., Band function with Epeak = 70 keV, alpha = -1.9, beta = -3.7).

[1] Goldstein et al. 2019 arXiv:1903.1259