GCN Circular 9650
Subject
GRB 090709B: Fermi GBM detection
Date
2009-07-10T15:53:17Z (15 years ago)
From
Charles Meegan at NASA/MSFC <charles.a.meegan@nasa.gov>
C. Meegan (USRA) and A. J. van der Horst (NASA/MSFC/ORAU)
report on behalf of the Fermi GBM Team:
"At 15:07:41.14 UT on 09 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090709B (trigger 268844863 / 090709630),
which was also detected by the SWIFT-BAT (GCN 9633).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 35 degrees.
The GBM light curve consists of two pulses
with a duration (T90) of about 32 s (8-1000 keV).
The time-averaged spectrum from T0-2.0 s to T0+27.6 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.01 +/- 0.16 and
the cutoff energy, parameterized as Epeak, is 130 +/- 24 keV
(chi squared 354 for 365 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(1.3 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.0 s in the 8-1000 keV band
is 2.0 +/- 0.3 ph/s/cm^2.
The temporal and spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."