GCN Circular 19901

P Veres (UAH) and C Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 17:19:39.15 UT on 10 September 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160910A (trigger 495220783 / 160910722).

The on-ground calculated location, using the GBM trigger data, is RA =
221.8, DEC = 39.6 (J2000 degrees, equivalent to 14 h 47 m, 39 d 38 '), with
an uncertainty of 1 degrees (radius, 1-sigma containment, statistical only;
there is additionally a systematic error which we have characterized as a
core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small
tail suffering a larger than 10 deg systematic error. [Connaughton et al.
2015, ApJS, 216, 32] ).

The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM
Flight Software owing to the high peak flux of the GRB. This ARR was
accepted and the spacecraft slewed to the GBM in-flight location. The
initial angle from the Fermi LAT boresight to the GBM ground location is 71
degrees.

The GBM light curve shows a single pulse with a duration (T90) of about
24.3 s (50-300 keV). The time-averaged spectrum from T0 to T0+32.3 s is
best fit by a Band function with Epeak = 347 +/- 9 keV, alpha = -0.78 +/-
0.01, and beta = -2.23 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is (8.41 +/- 0.06)E-5
erg/cm^2. The 1-sec peak photon flux measured starting from T0+8.2 s in the
10-1000 keV band is 76.5 +/- 0.5 ph/s/cm^2.

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