GCN Circular 32533

S. Dalessi, C. Meegan and P. Veres (all UAH)
report on behalf of the Fermi GBM Team:

"At 14:05:26.48 UT on 07 September 2022, the Fermi Gamma-Ray Burst
Monitor (GBM) triggered and located GRB 220907A (trigger 684252331 /
220907587), which was also detected by the Swift/BAT (Page et al.
2022, GCN 32526
Not found
 
 
, 32530
Not found
 
 
). The Fermi GBM Final Real-time Localization
(GCN 32525
Not found
 
 
) is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 50 degrees.

The GBM light curve shows a single peak with a duration (T90) of about
9 s (50-300 keV). The time-averaged spectrum from T0-2.8 s to T0+5.4 s
is best fit by a power law function with index = -1.48 +/- 0.07.

The event fluence (10-1000 keV) in this time interval is (1.13 +/-
0.12)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from
T0+1.02 s in the 10-1000 keV band is 2.32 +/- 0.24 ph/s/cm^2.

A power law function with an exponential high-energy cutoff fits the
spectrum equally well.  The power law index is -1.01 +/- 0.29 and the
cutoff energy, parameterized as Epeak, is 320 +/- 170 keV and fluence
(1.02 +/-0.22)E-6 erg/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"