TITLE: GCN CIRCULAR NUMBER: 23810 SUBJECT: GRB 190129A: Fermi GBM detection DATE: 19/01/29 21:36:58 GMT FROM: Bagrat Mailyan at UAH E. Bissaldi (Politecnico & INFN Bari), B. Mailyan (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 12:21:41.87 UT on 29 January 2019, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 190129A (trigger 570457306 / 190129515), which was also detected by MAXI/GSC (Nakahira et al. 2019, GCN 23806). The GBM on-ground location is consistent with the MAXI/GSC position. The angle from the Fermi LAT boresight at the GBM trigger time is 118 degrees. The GBM light curve shows/consists of a single peak with a duration (T90) of about 8.7 s (50-300 keV). The time-averaged spectrum from T0-1 s to T0+4 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.37 +/- 0.23 and the cutoff energy, parameterized as Epeak, is 78 +/- 19 keV. The event fluence (10-1000 keV) in this time interval is (9 +/- 1)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.38 s in the 10-1000 keV band is 3.7 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."