GCN Circular 32030
Subject
GRB 220511A: Fermi GBM observation
Date
2022-05-12T16:33:33Z (2 years ago)
From
Peter Veres at UAH <veresp@gmail.com>
P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:
"At 13:41:56.87 UT on 11 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220511A (trigger 673969321 / 220511571)
which was also detected by Swift/BAT-GUANO (DeLaunay et al., GCN 32023).
The Fermi GBM Final Real-time Localization (GCN 32018) is consistent
with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 112 degrees.
The GBM light curve consists of a single FRED-like pulse
with a duration (T90) of about 4.2 s (50-300 keV).
The time-averaged spectrum from T0 to T0+5.7 s is best fit by
a power law function with an exponential
high-energy cutoff. The power law index is -0.85 +/- 0.05 and
the cutoff energy, parameterized as Epeak, is 199 +/- 11 keV.
The event fluence (10-1000 keV) in this time interval is
(7.62 +/- 0.23)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.58 s in the 10-1000 keV band
is 20.3 +/- 0.5 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 155 +/- 14 keV, alpha = -0.70 +/- 0.08 and beta = 2.18 +/- 0.12.
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/"