TITLE:   GCN CIRCULAR
NUMBER:  35778
SUBJECT: GRB 240222A: Fermi GBM Observation
DATE:    24/02/22 23:39:37 GMT
FROM:    Joe Mangan at IJCLab <joseph.mangan@ijclab.in2p3.fr>

J. Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 08:51:31.47 UT on 22 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240222A (trigger 730284696/240222369).
which was also detected by Swift BAT (P. D'Avanzo et al. 2024, GCN 35770).
The Fermi GBM on-ground location is consistent with the Swift BAT position.

The angle from the Fermi LAT boresight is 109 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 3.8 s (50-300 keV). The time-averaged spectrum
from T0-5.9 to T0+3.3 s is best fit by
a simple power law function with index -1.4 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(9.2 +/- 1.9)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.19 s in the 10-1000 keV band is 4 +/- 0.7 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/"