TITLE: GCN CIRCULAR NUMBER: 36479 SUBJECT: GRB 240513A: Fermi GBM observation DATE: 24/05/14 15:49:19 GMT FROM: Elisabetta Bissaldi at Politecnico and INFN Bari E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 07:22:02 UT on 13 May 2024, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 240513A (trigger 737277727 / 240513307), which was also detected by the Fermi/LAT (Cutini et al. 2024, GCN 36462) and AstroSat CZTI (Joshi et al. 2024, GCN 36455). The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 34 degrees. The GBM light curve consists of two emission episodes with a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0-0.3 s to T0+6.5 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.87 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 1700 +/- 400 keV. The event fluence (10-1000 keV) in this time interval is (3.93 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.8 s in the 10-1000 keV band is 4.1 +/- 0.2 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/"