TITLE: GCN CIRCULAR NUMBER: 17623 SUBJECT: GRB 150323B: Fermi GBM observation DATE: 15/03/23 17:24:20 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 09:28:39.21 UT on 23 March 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150323B (trigger 448795722 / 150323395), which was also detected by the Swift (Cummings et al. 2015, GCN 17619). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 69 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 54 s (50-300 keV). The time-averaged spectrum from T0-0.512 s to T0+60.929 s is best fit by a Band function with Epeak = 99.14 (+4.50/-6.02) keV, alpha = -0.89 (+0.07/-0.05), and beta = -2.04 (+0.03/-0.03). The event fluence (10-1000 keV) in this time interval is (2.19 +/- 0.03)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+1.152 s in the 10-1000 keV band is 8.2 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."