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GCN Circular 33879

GRB 230525A: Fermi GBM Detection
2023-05-25T17:10:06Z (14 days ago)
S. Bala (USRA), C. Fletcher (USRA), O.J. Roberts (NASA/MSFC) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 10:46:08.33 UT on 25 May 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230525A (trigger 706704373/230525449). The Fermi GBM Final Real-time Localization was reported in GCN 33877. The angle from the Fermi LAT boresight is 19 degrees. The GBM light curve consists of single peak with a duration (T90) of 0.12 s (50-300 keV). The time-averaged spectrum from T0-0.06 to T0+0.06 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.80 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 789 +/- 148 keV. The event fluence (10-1000 keV) in this time interval is (8.6 +/- 0.4)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 25 +/- 1 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: For Fermi GBM data and info, please visit the official Fermi GBM Support Page:"
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