TITLE: GCN CIRCULAR NUMBER: 35680 SUBJECT: GRB 240204A: Fermi GBM Observation DATE: 24/02/05 21:17:16 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 15:07:38.68 UT on 04 February 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240204A (trigger 728752063/240204630), which was also detected by Swift XRT (S. B. Cenko et al. 2024, GCN 35666). The Fermi GBM on-ground location is consistent with the Swift XRT position. The angle from the Fermi LAT boresight is 101 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 15.9 s (50-300 keV). The time-averaged spectrum from T0-6.5 to T0+34.5 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.03 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 84 +/- 2 keV. The event fluence (10-1000 keV) in this time interval is (1.69 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+12 s in the 10-1000 keV band is 32.9 +/- 0.5 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 79 +/- 2 keV, alpha = -0.97 +/- 0.04 and beta = -3.0 +/- 0.2. 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/35680. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...