GCN Circular 33011

GRB 221201A: Fermi GBM observation

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

"At 12:24:45.31 UT on 01 December 2022, the Fermi Gamma-Ray Burst 
Monitor (GBM)
triggered and located GRB 221201A (trigger 691590290 / 221201517).

This event was also observed by Swift/BAT and�� Swift/XRT (GCN 32998
Not found
 
 
).

The GBM position is reported in the Fermi-GBM Final on-ground 
Localization (GCN 32997
Not found
 
 
)
and is consistent with the Swift position.
The angle from the Fermi LAT boresight is 125 degrees.

The GBM light curve shows a single pulse with a duration (T90) of about 
29 s (50-300 keV).
The time-averaged spectrum from T0-0 s to T0+15 s is best fit by a Band 
function
with Epeak = 144 +/- 7 keV, alpha = -0.57 +/- 0.07, and beta = -2.5 +/- 0.1

The event fluence (10-1000 keV) in this time interval is (1.59 +/- 
0.03)E-05 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+6.8 s in the 
10-1000 keV band
is 20.5 +/- 0.6 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/"