TITLE: GCN CIRCULAR NUMBER: 36903 SUBJECT: GRB 240718A: Fermi GBM Observation DATE: 24/07/18 17:41:09 GMT FROM: Cuán de Barra at UCD <cuan.debarra@ucdconnect.ie> C. de Barra (UCD) and C. Meegan (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 06:29:00.43 UT on 18 July 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240718A (trigger 742976945/240718270), which was also detected by Fermi-LAT (Depalo et al. 2024, GCN 36901), SPI-ACS, and SVOM/GRM (SVOM/GRM Team 2024, GCN 36900). The Final Real-time Localization was reported previously (Fermi GBM Team 2024, GCN 36898).The Fermi GBM on-ground location is consistent with the Fermi-LAT position. The angle from the Fermi LAT boresight is 52 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 59 s (50-300 keV). The time-averaged spectrum from T0-2.7 to T0+59.8 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.00 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 1626 +/- 106 keV. The event fluence (10-1000 keV) in this time interval is (5.81 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.26 s in the 10-1000 keV band is 29.9 +/- 0.5 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/36903. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...