TITLE: GCN CIRCULAR NUMBER: 25131 SUBJECT: GRB 190720A: Fermi GBM detection DATE: 19/07/20 23:13:48 GMT FROM: C. Michelle Hui at MSFC/Fermi-GBM C. M. Hui (NASA-MSFC) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: At 14:42:09.78 UT on 20 July 2019, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 190720A (trigger 585326534/190720613). The on-ground calculated location, using the GBM trigger data, is RA = 202.72 , DEC = +41.78 (J2000 degrees, equivalent to 13h 30m, +41d 42.0'), with an uncertainty of 1.16 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error [Connaughton et al. 2015, ApJS, 216, 32] ). The angle from the Fermi LAT boresight is 59.00 degrees. The GBM light curve shows/consists of single peak with a duration (T90) of about 6.1s (50-300 keV). The time-averaged spectrum from T0-0.0s to T0+8.8s is adequately fit by a Band function with Epeak = 182 +/- 6 keV, alpha = -0.89 +/- 0.02, and beta = -2.21 +/- 0.04. The event fluence (10-1000 keV) in this time interval is (2.74 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.5s in the 10-1000 keV band is 48.2 +/- 0.5 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/