GCN Circular 32241

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

"At 09:10:19.59 UT on 18 June 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220618A (trigger 677236224 / 220618382)
which was also detected by the Swift/BAT (Troja et al. 2022, GCN 32214
Not found
 
 
).

The angle from the Fermi LAT boresight at the GBM trigger time is 35
degrees.

The GBM light curve consists of a single peak followed
by some extended emission with a duration (T90) of about 44 s (50-300 keV).
The time-averaged spectrum from T0-4.096 s to T0+24.576 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.30 +/- 0.13  and
the cutoff energy, parameterized as Epeak, is 126 +/- 8 keV.

The event fluence (10-1000 keV) in this time interval is
(3.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+10.05 s in the 10-1000 keV band
is 2.3 +/- 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/"