TITLE:   GCN CIRCULAR
NUMBER:  21840
SUBJECT: GRB 170906B: Fermi GBM detection
DATE:    17/09/06 21:33:57 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH) and and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 00:55:40.85 UT on 06 September 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170906B (trigger 526352145 / 170906039).
which was also detected by Swift (Sbarufatti et al. 2017, GCN 21822).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 53
degrees.

The GBM light curve shows a two-peaked emission
with a duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0-0.0 s to T0+12.8 s is
well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.11 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 59 +/- 4 keV.

The event fluence (10-1000 keV) in this time interval is
(2.7 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.1 s in the 10-1000 keV band
is 10.3 +/- 0.4 ph/s/cm^2.

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