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GCN Circular 31166

Subject
GRB 211124A: Fermi GBM Observation
Date
2021-12-03T22:29:45Z (2 years ago)
From
Boyan A. Hristov at UAH <bah0046@uah.edu>
Boyan A. Hristov (UAH) reports on behalf of the Fermi GBM Team:

"At 02:29:53.56 UT on 24 November 2021, the Fermi Gamma-Ray Burst
Monitor (GBM) triggered and located GRB 211124A (trigger 659413798
/ 211124104),

The results from Swift/BAT + NITRATES (DeLaunay et al. 2021, GCN 31113)
are consistent with a burst coming from out of the FOV,
which is also consistent with the GBM in-flight location.

The GBM location, using the GBM trigger data, is RA = 94.967,
DEC = -61.433 (J2000 degrees, equivalent to 06h 20m, -61d 26'), with a
statistical uncertainty of 5.98 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which we
have characterized as a core-plus-tail model, with 90% of GRBs having
a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

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

The GBM light curve shows two peaks with a duration (T90) of about
0.5 s (50-300 keV).  The time-averaged spectrum from T0-0.128 s to
T0+0.576 s is well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.65 +/- 0.16 and the
cutoff energy, parameterized as Epeak, is 357.50 +/- 80.10 keV.
The event fluence (10-1000 keV) in this time interval is
(1.004 +/- 0.120)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0 s in the 10-1000 keV band is 27 +/- 3 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/"
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