TITLE:   GCN CIRCULAR
NUMBER:  21869
SUBJECT: GRB 170911A: Fermi GBM observation
DATE:    17/09/12 11:49:28 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE), R. Hamburg (UAH), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 06:24:22.79 UT on 11 September 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170911A (trigger 526803867 / 170911267)
which was also detected by the MAXI GSC
(Takao et al. 2017, GCN 21858)
The GBM on-ground location is consistent with the MAXI position.

The angle from the Fermi LAT boresight at the GBM trigger time is 43 degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 20 s (50-300 keV).
The time-averaged spectrum from T0-3.072 s to T0+4.096 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.2 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 260 +/- 120 keV


The event fluence (10-1000 keV) in this time interval is
(9.5 +/- 1.7)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-1.79 s in the 10-1000 keV band
is 1.96 +/- 0.17 ph/s/cm^2.

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