GCN Circular 22233
S. Poolakkil (UAH), C. Meegan (UAH) and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "At 11:49:15.26 UT on 10 December 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 171210A (trigger 534599360 / 171210493) which was also detected by the Fermi LAT (E. Bissaldi et al. 2017, GCN 22228). The GBM on-ground location is consistent with the LAT position. 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 best location is 51 degrees. The GBM light curve consists of a single bright peak with a duration (T90) of about 143 s (50-300 keV). The time-averaged spectrum from T0-1.02 s to T0+103.42 s is best fit by a Band function with Epeak= 145 +/- 3 keV, alpha = -0.65 +/- 0.02 and beta = -2.34 +/- 0.05. The event fluence (10-1000 keV) in this time interval is (7.33 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.46 s in the 10-1000 keV band is 16.7 +/- 0.36 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."