GCN Circular 11006
Subject
GRB 100728A: Fermi GBM observation
Date
2010-07-28T10:06:01Z (14 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 02:17:30.61 UT on 28 July 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100728A (trigger 301976252 / 100728095),
which was also detected by the Swift-BAT (Cannizzo et al. 2008, GCN 11004)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 58.6 degrees.
The GBM light curve shows a multi-peaked structure
with a duration (T90) of about 162.9 +/- 0.9 s (50 - 300 keV).
The time-averaged spectrum from T0-8.192 s to T0+191.491 s is
well fit by a power law function with an exponential
high energy cutoff. The power law index is -0.76 +/- 0.01 and
the cutoff energy, parameterized as Epeak, is 353.7 +/- 6.7 keV
(Castor C-STAT 3540 for 727 d.o.f.) .
The event fluence (8-1000 keV) in this time interval is
(1.291 +/- 0.008)E-04 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+80.2 s in the 8-1000 keV band is 10.8 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well (Castor C-STAT 3537 for 726
d.o.f.) with Epeak= 344.3 +9.1/-7.9 keV, alpha = -0.75 +/- 0.01 and
beta = -3.04 +0.23/-0.57.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."