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GCN Circular 32369

Subject
GRB 220711B: Fermi GBM Detection
Date
2022-07-12T00:49:33Z (2 years ago)
From
Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu>
S. Lesage (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 18:16:28.06 UT on 11 July 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220711B (trigger 679256193/220711761)
which was also detected by Swift-BAT (A. D'Ai et al. 2022, GCN 32366).
The Fermi GBM Final Real-time Localization (GCN 32365) is consistent
with the Swift-BAT position.

The angle from the Fermi LAT boresight is 101 degrees.

The GBM light curve consists of a multipeaked emission episode with a
duration (T90)
of about 82 s (10-1000 keV). The time-averaged spectrum
from T0-40 to T0+61 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.39 +/- 0.07 and the cutoff energy,
parameterized as Epeak, is 81 +/- 6 keV.

The event fluence (10-1000 keV) in this time interval is
(1.02 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.4 s in the 10-1000 keV band is 6.0 +/- 0.4 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 79 +/- 8 keV, alpha = -1.37 +/- 0.09 and beta = -2.93 +/- 0.71.

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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