GCN Circular 33758
Subject
GRB 230506B: Fermi GBM detection
Date
2023-05-10T21:19:49Z (a year ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
O.J. Roberts (USRA/NASA-MSFC), S. Bala (USRA), C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 12:45:18.77 UT on 06 May 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230506B (trigger 705069923 / 230506531), which was
also detected by the Swift/BAT (S. Dichiara et al. 2023, GCN 33729 and
S.D. Barthelmy et al. 2023, GCN 33742). The GBM on-ground location is
consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 47 degrees.
The GBM light curve consists of multiple short bursts
with a duration (T90) of about 38 s (50-300 keV).
The time-averaged spectrum from T0-0.8 s to T0+39.2 s is best fit by
a power law function with an exponential
high-energy cutoff. The power law index is -1.28 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 1767 +/- 576 keV
The event fluence (10-1000 keV) in this time interval is
(1.13 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+10.4 s in the 10-1000 keV band
is 8.1 +/- 0.3 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/"