TITLE: GCN CIRCULAR NUMBER: 22249 SUBJECT: GRB 171212B: Fermi GBM observation DATE: 17/12/12 22:51:03 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (Politecnico & INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 10:24:18.51 UT on 12 December 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 171212B (trigger 534767063 / 171212434), which was also detected by the Fermi-LAT (Kocevski et al. 2012, GCN 22247). The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 11 degrees. The GBM light curve consists of a multipeak emission episode with a duration (T90) of about 32 s (50-300 keV). The time-averaged spectrum from T0 to T0+32 s is adequately fit by a Band function with Epeak = 74 +/- 9 keV, alpha = -0.95 +/- 0.13, and beta = -2.32 +/- 0.15. The event fluence (10-1000 keV) in this time interval is (5.744 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+27 s in the 10-1000 keV band is 5.0 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."