GCN Circular 28326
Subject
GRB 200829A: Fermi GBM detection
Date
2020-08-30T17:12:33Z (4 years ago)
From
Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu>
S. Lesage (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 13:58:14.66 UT on 29 August 2020, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 200829A (trigger 620402299 / 200829582)
which was also detected by the Swift Burst Alert Telescope (BAT)
(M. H. Siegel et al. 2020, GCN 28307). GBM initially triggered on a weak
spike ~15-20 s before the very bright emission. The GBM on-ground location
is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is ~148
degrees.
The GBM light curve shows an exceptionally bright long GRB
with a duration (T90) of about 6.9 s (50-300 keV).
The time-averaged spectrum from T0+16.64 s to T0+25.856 s is
best fit by a Band function with Epeak = 336.8 +/- 4.3 keV,
alpha = -0.43 +/- 0.01, and beta = -2.4 +/- 0.02
The event fluence (10-1000 keV) in this time interval is
(2.069 +/- 0.009)E-04 erg/cm^2.
The 1.024-sec peak photon flux measured starting from T0+19.7 s in
the 10-1000 keV band is 213.9 +/- 1.7 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/"