[vsnet-grb-info 8117] GRB 090709B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9650
SUBJECT: GRB 090709B: Fermi GBM detection
DATE:    09/07/10 15:53:17 GMT
FROM:    Charles Meegan at NASA/MSFC  <charles.a.meegan at 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."