GCN Circular 31778

R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 12:48:30.66 UT on 17 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220317A (trigger 669214115 / 220317534).
which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2022, GCN
31766
Not found
 
 
).

The angle from the Fermi LAT boresight at the GBM trigger time is 48
degrees.

The GBM light curve shows two peaks with a duration (T90)
of about 14 s (50-300 keV). The time-averaged spectrum
from T0-6.1 s to T0+8.2 s is best fit by a power law
function with an exponential high-energy cutoff.
The power law index is -1.1 +/- 0.2 and the cutoff
energy, parameterized as Epeak, is 248 +/- 96 keV.

The event fluence (10-1000 keV) in this time interval is
(1.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.4 s in the 10-1000 keV band
is 1.6 +/- 0.2 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/"