GCN Circular 32437
Subject
GRB 220730A: Fermi GBM detection
Date
2022-08-02T15:36:47Z (2 years ago)
From
Suraj Poolakkil at UAH <sp0076@uah.edu>
S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 15:48:55.032 UT on 30 July 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220730A (trigger 680888940 / 220730659)
which was also detected by the Swift/BAT (Dichiara et al. 2022, GCN 32431).
The angle from the Fermi LAT boresight at the GBM trigger time is 121
degrees.
The GBM light curve consists of a single peak followed
by some extended emission with a duration (T90) of about 0.16 s (50-300
keV).
The time-averaged spectrum from T0-0.064 s to T0+0.192 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.34 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 488 +/- 84 keV.
A Band function fits equally well, with Epeak = 412 +/- 97 keV,
alpha = -0.21 +/- 0.25 and beta = -2.47 +/- 0.68.
The event fluence (10-1000 keV) in this time interval is
(1.06 +/- 0.09)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0 s in the 10-1000 keV band
is 24.9 +/- 2.2 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/"