GCN Circular 27025
R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 23:04:55.34 UT on 20 January 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200120A (trigger 601254300 / 200120962). GRB 200120A was also detected by Insight/HMXT (GCN 26840) and AstroSat/CZTI (GCN 26851), and localized by the IPN (GCN 26856). Approximately 820 s after the GBM trigger, SRG/eRosita detected and localized an X-ray transient consistent with being the afterglow of GRB 200120A (Weber et al. 2019, GCN 26988). The Fermi GBM Final Real-time Localization (GCN 26831) is consistent with the SRG/eRosita position. The angle from the Fermi LAT boresight at the GBM trigger time is 148 degrees. The GBM light curve shows a broad, single-peaked structure with a duration (T90) of about 13 s (50-300 keV). The time-averaged spectrum from T0-6. to T0+10. s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.92 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 239 +/- 22 keV. The event fluence (10-1000 keV) in this time interval is (9.4 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.0 s in the 10-1000 keV band is 13 +/- 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/"