TITLE:   GCN CIRCULAR
NUMBER:  35680
SUBJECT: GRB 240204A: Fermi GBM Observation
DATE:    24/02/05 21:17:16 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

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

"At 15:07:38.68 UT on 04 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240204A (trigger 728752063/240204630),
which was also detected by Swift XRT (S. B. Cenko et al. 2024, GCN 35666).
The Fermi GBM on-ground location is consistent with the Swift XRT position.

The angle from the Fermi LAT boresight is 101 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 15.9 s (50-300 keV). The time-averaged spectrum
from T0-6.5 to T0+34.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.03 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 84 +/- 2 keV.

The event fluence (10-1000 keV) in this time interval is
(1.69 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+12 s in the 10-1000 keV band is 32.9 +/- 0.5 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 79 +/- 2 keV, alpha = -0.97 +/- 0.04 and beta = -3.0 +/- 0.2.

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/"