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GCN Circular 31760

GRB 220311A: Fermi GBM observation
2022-03-15T14:57:05Z (2 years ago)
Rachel Hamburg at UAH <>
R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 16:33:18.40 UT on 11 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220311A (trigger 668709203 / 220311690), which
was also detected by the INTEGRAL/IBAS (Mereghetti et al. 2022, GCN 31740).
The Fermi GBM Final Real-time Localization (GCN 31744) is largely
consistent with the INTEGRAL position.

The angle from the Fermi LAT boresight at the GBM trigger time is 111

The GBM light curve shows a single spike with a duration (T90) of about
10 s (50-300 keV). The time-averaged spectrum from
T0-5.1 s to T0+0.0 s is adequately a simple power law function with index
-1.55 +/- 0.11.

The event fluence (10-1000 keV) in this time interval is
(1.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-4.7 s in the 10-1000 keV band
is 1.8 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:

For Fermi GBM data and info, please visit the official Fermi GBM Support
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