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GCN Circular 31988

Subject
GRB 220501A: Fermi GBM observation
Date
2022-05-02T13:53:38Z (2 years ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
O.J. Roberts (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 19:51:50.74 UT on 01 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220501A (trigger 673127515 / 220501828), which
was also detected by Swift/BAT (A. D'Ai et al. 2022, GCN 31982). The
Fermi GBM Final Real-time Localization (GCN 31983) is consistent with the
Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 94 degrees.

The GBM light curve shows a FRED-like burst
with a duration (T90) of about 51 s (50-300 keV).
The time-averaged spectrum from T0-3.6 s to T0+47.6 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.49 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 114 +/- 11 keV

The event fluence (10-1000 keV) in this time interval is
(3.53 +/- 0.24)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.0 s in the 10-1000 keV band
is 2.5 +/- 0.2 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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