[vsnet-grb-info 6915] GRB 081109: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8505
SUBJECT: GRB 081109: Fermi GBM detection
DATE:    08/11/09 15:56:47 GMT
FROM:    Andreas von Kienlin at MPE  <azk at mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 07:02:02.42 UT on 09 November 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081109 (trigger 247906923 / 081109293), which was 
also detected by the SWIFT (S. Immler et al. 2008, GCN 8500).
The GBM on-ground location is consistent with the Swift position.

The GBM light curve shows a single peak
with a duration (T90) of about 45 s (8-1000 keV). 
The time-averaged spectrum from T0-6.144 s to T0+26.624 s is 
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.28 +/- 0.09 and
the cutoff energy, parameterized as Epeak is 240 +/- 60 keV.
(chi squared 510 for 478 d.o.f.)
The event fluence (8-1000 keV) in this time interval is 
(6.53 +/- 0.43)E-06 erg/cm^2. The 1-sec photon flux measured 
starting from T0+9.216 s in the 8-1000 keV band 
is  3.2 +/- 0.3  ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."