TITLE: GCN CIRCULAR NUMBER: 25703 SUBJECT: LIGO/Virgo S190910d: No counterpart candidates in AGILE-MCAL observations DATE: 19/09/10 08:01:53 GMT FROM: Claudio Casentini at INAF-IAPS C. Casentini, G. Piano, M. Tavani, M. Cardillo, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW event S190910d at T0 = 2019-09-10 01:26:19 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering -/+ 15 sec from the LIGO/Virgo T0. At the T0, about 60% of the S190910d 90 c.l. localization region was accessible to the AGILE MCAL. Three-sigma upper limits (ULs) are obtained for a 1 s integration time at different celestial positions within the accessible S190910d localization region, from a minimum of 1.18E-06 erg cm^-2 to a maximum of 2.89E-06 erg cm^-2 (assuming as spectral model a single power law with photon index 1.5). The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.