TITLE: GCN CIRCULAR NUMBER: 17216 SUBJECT: GRB 141221A: Fermi GBM observation DATE: 14/12/22 08:29:06 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team: "At 08:07:11.22 UT on 21 Dec 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141221A (trigger 440842034 / 141221338), which was also detected by Swift (Sonbas et al. 2014, GCN 17206). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is about 76 degrees. The GBM light curve consists of two pulses with a duration (T90) of about 23.8 s (50-300 keV). The time-averaged spectrum from T0-1.024 s to T0+17.408 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.07 +/- 0.13 and the cutoff energy, parameterized as Epeak, is 152.4 +/- 28.5 keV. The event fluence (8-1000 keV) in this time interval is (3.4 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0-0.192 s in the 8-1000 keV band is 5.4 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."