GCN Circular 34869

S. Bala (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 18:56:58.30 UT on 20 October 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231020A (trigger 719521023/231020790).

The Fermi GBM Final Real-time Localization is reported in GCN 34856
Not found
 
 
.

The GBM light curve consists of a single bright peak with a duration (T90)
of about 9.3 s (50-300 keV). The time-averaged spectrum
from T0-0.5 to T0+21 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.34 +/- 0.01 and the cutoff energy,
parameterized as Epeak, is 145 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is
(3.81 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6.6 s in the 10-1000 keV band is 87.2 +/- 0.8 ph/s/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/"