TITLE: GCN CIRCULAR NUMBER: 30142 SUBJECT: GRB 210606B: AGILE detection DATE: 21/06/07 11:44:52 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), F. Verrecchia, C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, A. Di Piano, V. Fioretti, 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 210606B at T0 = UTC 2021-06-06 22:41:03 s (UTC), reported by Fermi/GBM (Trigger no. 644712030), GECAM (GCN #39138), and BALROG (GCN #39139). 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 ~35 s and released a total number of 3120 counts in the SA detector (above a background rate of 66 Hz), 43110 counts in the MCAL detector (above a background rate of 1250 Hz), and 125100 counts in the AC detector (above a background rate of 3660 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/GRB210606B_AGILE_RM.png . The event also triggered a partial high time resolution MCAL data acquisition at T = UTC 2021-06-06 22:41:13.18 +/- 0.01 s, whose light curve can be found at: http://www.agilescienceapp.it/notices/073374_GRB_550104073.181294.png . Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.