TITLE:   GCN CIRCULAR
NUMBER:  31755
SUBJECT: GRB 220310C: Fermi GBM observation
DATE:    22/03/14 02:11:55 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 22:23:51.43 UT on 10 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220310C (trigger 668643836 / 220310933)
which was also detected by the Swift/BAT (Tohuvavohu et al., GCN 31746).
The Fermi GBM Final Real-time Localization (GCN 31735) is consistent
with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 30 degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 16.4 s (50-300 keV).
The time-averaged spectrum from T0-6.1 s to T0+16.4 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.74 +/- 0.30 and
the cutoff energy, parameterized as Epeak, is 180 +/- 51 keV.

The event fluence (10-1000 keV) in this time interval is
(1.52 +/- 0.27)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-1.7 s in the 10-1000 keV band
is 1.28 +/- 0.18 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/"