TITLE: GCN CIRCULAR NUMBER: 14078 SUBJECT: GRB 121211A: Fermi GBM observation DATE: 12/12/13 09:02:10 GMT FROM: Hoi-Fung Yu at MPE David Yu (MPE) reports on behalf of the Fermi GBM Team: "At 13:47:03.59 UT on 11 December 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 121211A (trigger 376926426 / 121211574) which was also detected by the Swift/BAT (Mangano et al. 2012, GCN 14057). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 74 degrees. The GBM light curve consists of a double peaked pulse with a duration (T90) of about 5.4 s (50-300 keV). The time-averaged spectrum from T0-3.072 s to T0+1.536 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.30 +/- 0.34 and the cutoff energy, parameterized as Epeak, is 95.96 +/- 12.60 keV. The event fluence (10-1000 keV) in this time interval is (4.825 +/- 0.507)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.768 s in the 10-1000 keV band is 2.402 +/- 0.202 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."