TITLE: GCN CIRCULAR NUMBER: 35974 SUBJECT: GRB 240318A: Fermi GBM Observation DATE: 24/03/21 21:31:30 GMT FROM: Lorenzo Scotton at UAH <lscottongcn@outlook.com> L. Scotton (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 02:51:01.82 UT on 18 March 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240318A (trigger 732423066/240318119), which was also detected by Glowbug (Cheung et al. 2024, GCN 35959) and Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35969). The Fermi GBM Final Real-time Localization was provided in GCN 35949. The angle from the Fermi LAT boresight is 53 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 8 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+11.0 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.5 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 112 +/- 8 keV. The event fluence (10-1000 keV) in this time interval is (2.1 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.1 s in the 10-1000 keV band is 4.5 +/- 0.3 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/35974. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...