TITLE:   GCN CIRCULAR
NUMBER:  31710
SUBJECT: GRB 220304A Fermi GBM detection
DATE:    22/03/08 16:11:39 GMT
FROM:    Boyan A. Hristov at UAH  <bah0046@uah.edu>

Boyan A. Hristov (UAH) and C. Meegan (UAH) report on behalf of
the Fermi GBM Team:

"At 05:28:58.79 UT on 04 March 2022, the Fermi Gamma-Ray Burst
Monitor (GBM) triggered and located GRB 220304A (trigger
668064543 / 220304228, GCN 31672), which was also detected by
the Swift/BAT-GUANO (DeLaunay et al. 2022, GCN 31677).

The GBM light curve consists of a single spike with a duration
(T90) of about 32 s (50-300 keV).  The time-averaged spectrum
from T0+3.072 s to T0+35.841 s is best fit by a Band function
with Epeak = 90 +/- 2 keV, alpha = -0.24 +/- 0.06, and beta =
-3.2 +/- 0.1.  The event fluence (10-1000 keV) in this time
interval is (59 +/- 0.7)E-6 erg/cm^2.  The 1-sec peak photon
flux measured starting from T0+15.488 s in the 10-1000 keV band
is 36 +/- 1 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/"