TITLE: GCN CIRCULAR NUMBER: 35578 SUBJECT: GRB 240115A: Fermi GBM Observation DATE: 24/01/19 15:36:32 GMT FROM: rachel.hamburg@ijclab.in2p3.fr R. Hamburg (CNRS/IN2P3) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 11:03:14.11 UT on 15 January 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240115A (trigger 727009399/240115461), which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35557). The Fermi Final Real-time Localization is reported in GCN 35537. The angle from the Fermi LAT boresight is 37 degrees. The GBM light curve consists of one main pulse with a duration (T90) of about 1.79 s (50-300 keV). The time-averaged spectrum from T0-0.26 to T0+0.77 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.7 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 450 +/- 137 keV. The event fluence (10-1000 keV) in this time interval is (4.8 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0+0.64 s in the 10-1000 keV band is 3.4 +/- 1.0 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/35578. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...