TITLE: GCN CIRCULAR NUMBER: 29991 SUBJECT: GRB 210511B: AGILE detection DATE: 21/05/11 17:11:19 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), V. Fioretti (INAF/OAS-Bologna), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, A. Di Piano, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected the long GRB 210511B at T0 = 2021-05-11 11:26:37 s (UTC), reported by Fermi/GBM (GCN #29988) and GECAM (GCN #29990). The burst is visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted ~12 s and released a total number of 2120 counts in the SA detector (above a background rate of 64 Hz), 15630 counts in the MCAL detector (above a background rate of 1260 Hz), and 48375 counts in the AC detector (above a background rate of 3865 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/GRB210511_AGILE_RM.png . Additional analysis of AGILE data is in progress.