GCN Circular 9662
Subject
GRB 090712: Fermi GBM observation
Date
2009-07-13T15:26:01Z (15 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 03:51:00.34 UT on 12 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090712 (trigger 269063462 / 090712160),
which was also detected by the SWIFT-BAT (Holland et al. 2008, GCN 9659,
Barthelmy et al., GCN 9660). The GBM on-ground location is consistent
with the Swift position.
The angle from the Fermi LAT boresight is 33 degrees.
The GBM light curve shows one single pulse with a duration (T90)
of about 72 s (8-1000 keV). The time-averaged spectrum from
T0-22.528 s to T0+49.153 s is best fit by a power law function
with an exponential high energy cutoff. The power law index
is -0.68 +/- 0.13 and the cutoff energy, parameterized as Epeak,
is 505 +/- 101 keV (chi squared 511 for 486 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(4.2 +/- 0.3)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+7.168 s in the 8-1000 keV band
is 0.63 +/- 0.04 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."