TITLE:   GCN CIRCULAR
NUMBER:  31908
SUBJECT: GRB 220412B: Fermi GBM observation
DATE:    22/04/15 20:33:00 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 17:06:49.04 UT on 12 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220412B (trigger 671476014 / 220412713)
which was also detected by the Swift/BAT (Gropp et al., GCN 31886).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 20 degrees.


The GBM light curve consists of a single pulse
with a duration (T90) of about 0.16 s (50-300 keV).
The time-averaged spectrum from T0-32 ms to T0+96 ms is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.70 +/-0.14 and
the cutoff energy, parameterized as Epeak, is 499 +/- 116 keV.

The event fluence (10-1000 keV) in this time interval is
(4.44 +/- 0.40)E-7 erg/cm^2. The 64-ms peak photon flux measured
starting from T0 in the 10-1000 keV band
is 17.2 +/- 1.2 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/"