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GCN Circular 9631

Subject
GRB 090708 : Fermi GBM detection
Date
2009-07-09T11:38:49Z (15 years ago)
From
Sheila McBreen at MPE <smcbreen@mpe.mpg.de>
S. McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:

"At 03:38:18.46 UT on 08 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090708 (trigger 268717100 / 090708152)
which was also detected by the Swift-BAT (Krimm et al. 2009, GCN 9621).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 55 degrees.

The GBM light curve consists of one pulse
with a duration of about 18 s (8-1000 keV).
The time-averaged spectrum from T0-2.0 s to T0+16.2 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.29 (+0.41/-0.34)
and the cutoff energy, parameterized as Epeak, is
47.5 (+12.0/-9.5) keV (chi squared 359 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
about 4E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.1 s in the 8-1000 keV band
is 1.0 +/- 0.2 ph/s/cm^2.

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