TITLE: GCN CIRCULAR NUMBER: 20545 SUBJECT: GRB 170127C (Fermi/GBM trigger 507173752): AGILE analysis DATE: 17/01/27 17:15:24 GMT FROM: Francesco Verrecchia at ASDC AGILE analysis of GRB 170127C (Fermi/GBM trigger 507173752) A. Ursi (INAF/IAPS), P. Munar-Adrover (INAF/IAPS), F. Verrecchia (ASDC and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), Y. Evangelista (INAF/IAPS), F. Lucarelli (ASDC and INAF/OAR), F. Fuschino (INAF/IASF-Bo), I. Donnarumma (INAF/IAPS), G. Minervini (INAF/IAPS), M. Marisaldi (INAF/IASF-Bo and Bergen University), A. Bulgarelli, V. Fioretti (INAF/IASF-Bo), C. Pittori (ASDC and INAF/OAR), G. Piano, A. Argan, E. Del Monte, L. Pacciani (INAF/IAPS), M. Cardillo (INAF/OA-Arcetri and INAF/IAPS), A. Giuliani (INAF/IASF-Mi), M. Pilia, A. Trois (INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), report on behalf of the AGILE Team: We performed an analysis of AGILE data of the GRB 170127C (Fermi/GBM trigger num 507173752; GCN #20543), which occurred at 2017-01-27 01:35:47.79 UTC. The Mini-CALorimeter (MCAL), sensitive in the energy range from 400 keV to 100 MeV, detected a short burst at T0 = 2017-01-27 01:35:47.9294 UTC, that triggered both the on-board 16 ms and 64 ms timescale hardware logic system. The MCAL light curve shows a sharp single peak, that lasted about 0.13 s and released a total number of ~980 counts above 400 keV in the detector, above an average background rate of 590 counts/s. The time-integrated spectrum measured between T0 and T0+0.13 s can be fit in the energy range 0.5 - 20 MeV with a power law with high-energy cut-off at 1.63 MeV, with photon index -1.64±0.19 and reduced chi-squared 1.08 (18 d.o.f.). As observed by MCAL, the burst fluence in the same energy range and time interval is 1.20±0.01e-6 erg cm-2. All quoted errors are at 90% confidence levels. SuperAGILE, sensitive in the energy range 18 to 60 keV, also clearly detected the burst with its ratemeters.