TITLE: GCN CIRCULAR NUMBER: 34831 SUBJECT: GRB 231018A: Fermi GBM Detection DATE: 23/10/18 17:36:50 GMT FROM: Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu> S. Lesage (UAH), E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 12:30:10 UT on 18 October 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231018A (trigger 719325015/231018521). The Fermi GBM Final Real-time Localization is reported in GCN 34826. The angle from the Fermi LAT boresight is 131 degrees. The GBM light curve consists of multiple multiple pulses with a duration (T90) of about 39.4 s (50-300 keV). The time-averaged spectrum from T0-4.6 to T0+92.7 s is best fit by a Band function with Epeak = 109 +/- 3 keV, alpha = -1.24 +/- 0.02, and beta = -2.56 +/- 0.05. The event fluence (10-1000 keV) in this time interval is (1.192 +/- 0.009)E-04 erg/cm^2. The 1-sec peak photon flux measured starting from T0+57 s in the 10-1000 keV band is 75 +/- 1 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/34831. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...