TITLE: GCN CIRCULAR NUMBER: 29605 SUBJECT: GRB 210306A: Fermi GBM observation DATE: 21/03/06 19:07:36 GMT FROM: Peter Veres at UAH P. Veres (UAH) reports on behalf of the Fermi GBM Team: "At 03:53:57.11 UT on 6 March 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210306A (trigger 636695642 / 210306162). which was also detected by the Swift/BAT (D'Elia et al., GCN 29597) and Fermi/LAT (Ohno et al., GCN 29602). The GBM on-ground location is consistent with the Swift position. The GBM light curve shows multiple overlapping pulses with a duration (T90) of about 9.5 s (50-300 keV). The time-averaged spectrum from T0-0.6 s to T0+11.6 s is best fit by a Band function with Epeak = 59.4 +/- 2.2 keV, alpha = -0.60 +/- 0.08, and beta = -2.53 +/- 0.06. The event fluence (10-1000 keV) in this time interval is (9.82 +/- 0.20)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+7.6 s in the 10-1000 keV band is 26.6 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"