TITLE: GCN CIRCULAR NUMBER: 34440 SUBJECT: GRB 230815A: Fermi GBM detection DATE: 23/08/15 20:38:44 GMT FROM: Bagrat Mailyan at Florida Tech B. Mailyan (Florida tech), A. von Kienlin (MPE) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 10:49:54.66 UT on 15 August 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230815A (trigger 713789399/230815451). which was also detected by Swift BAT (N. J. Klingler et al. 2023, GCN 34434). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 159 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 5.2 s (50-300 keV). The time-averaged spectrum from T0+0.002 to T0+3.264 s is best fit by a Band function with Epeak = 235 +/- 25 keV, alpha = -0.6 +/- 0.1, and beta = -2.22 +/- 0.09. The event fluence (10-1000 keV) in this time interval is (1.20 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.1 s in the 10-1000 keV band is 27 +/- 2 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/"