TITLE:   GCN CIRCULAR
NUMBER:  35132
SUBJECT: GRB 231118B: Fermi GBM observation
DATE:    23/11/20 03:32:59 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

C. de Barra (UCD) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 22:34:14.86 UT on 18 November 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231118B (trigger 722039659/231118940).

The Fermi GBM Final Real-time Localization is reported in GCN 35111.
The angle from the Fermi LAT boresight is 83 degrees.

The GBM light curve consists of a single bright peak 
with a duration (T90) of about 6 s (50-300 keV). 
The time-averaged spectrum from T0+0.1 to T0+7.9 s 
is best fit by a Band function with Epeak = 127.9 +/- 3.4 keV, 
alpha = -0.36 +/- 0.04, and beta = -2.89 +/- 0.13

The event fluence (10-1000 keV) in this time interval is
(1.3 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.7 s in the 10-1000 keV band is 21.7 +/- 0.4 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/"