GCN Circular 35610
Subject
Fermi GBM Sub-Threshold Detection of GRB 240123A
Date
2024-01-23T19:36:21Z (a year ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
L. Scotton (UAH) reports on behalf of the Fermi-GBM Team:
Swift-BAT detected GRB 240123A at 11:05:46 UT (D'Ai et al. 2024, GCN 35602). 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 false alarm rate of 3.9e-05 Hz and a location consistent with
the Swift-BAT event, using the standard search protocol with a S/N of 13.
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