TITLE: GCN CIRCULAR NUMBER: 13214 SUBJECT: Subject: GRB 120403B: Fermi GBM Observation DATE: 12/04/04 15:35:26 GMT FROM: Veronique Pelassa at UAH George Younes (USRA) reports on behalf of the Fermi GBM Team: "At 20:33:58.49 UT on April 03, 2012, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 120403B (trigger 355178040 / 120403857) which was triggered and detected by Swift (D'Elia et al., GCN 13203). The on-ground calculated location, using the Fermi GBM trigger data is consistent with the Swift location. The GBM light curve shows a single event with a duration (T90) of about 4 s (50-300 keV). The time-averaged spectrum from T0-1.792 s to T0 is well fit by a power law with index -1.51 +/- 0.08. A power law with an exponential high-energy cutoff fits the spectrum equally well. The power law index is -0.9 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 182 +/- 74 keV. The event fluence (10-1000 kev) in this time interval is (4.6 +/- 0.6)E-07 erg/s-cm^2. The 1-s peak photon flux starting at T0-0.896 s in the 10-1000 keV range is 1.7 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."