TITLE: GCN CIRCULAR NUMBER: 30499 SUBJECT: GRB 210723A: Fermi GBM Observation DATE: 21/07/25 01:23:27 GMT FROM: Suraj Poolakkil at UAH S. Lesage (UAH), B. Hristov (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: At 14:46:07 UT on 23 July 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210723A (trigger 648744372/210723615). which was also detected by Swift BAT (T. Sbarrato et al. 2021, GCN 30485) The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 94 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 43 s (10-1000 keV). The time-averaged spectrum from T0+1.5 to T0+36.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.67 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 113 +/- 5 keV. The event fluence (10-1000 keV) in this time interval is (7.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1 s in the 10-1000 keV band is 4.7 +/- 0.3 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/"