GCN Circular 31142

E. Bissaldi (Politecnico and INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 09:51:06.36 UT on 29 November 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 211129A (trigger 659872271 / 211129410),
which was also detected by the Swift/BAT (Gropp et al. 2021, GCN 31136
Not found
 
 
).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 22 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 111 s (50-300 keV).
The time-averaged spectrum from T0-8 s to T0+41 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.54 +/- 0.09 and
the cutoff energy, parameterized as Epeak, is 220 +/- 90 keV.

The event fluence (10-1000 keV) in this time interval is
(4.3 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+27 s in the 10-1000 keV band
is 2.81 +/- 0.22 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/"