TITLE: GCN CIRCULAR NUMBER: 25705 SUBJECT: LIGO/Virgo S190910d: no counterpart candidates in AGILE-GRID observations DATE: 19/09/10 08:23:57 GMT FROM: Giovanni Piano at INAF-IAPS G. Piano, C. Casentini (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), 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 01:26:19.243 UTC a preliminary analysis of the AGILE exposure at T0 shows that the Gamma-Ray Imaging Detector (GRID) exposure covered the 11% of the 90% c.l. localization region (LR) (19% of 90% c.l. localization region (LR) is occulted by Earth). We performed an analysis of the GRID data in the energy range 50 MeV - 10 GeV on T0. No candidate gamma-ray transient was detected. The following preliminary GRID values of 3-sigma upper limit (UL) are obtained: - from 7.5e-07 to 4.0e-06 erg cm^-2 s^-1, with exposure of about 11% of the LR over the time interval (T0 - 2 s; T0 + 2 s); - from 6.1e-07 to 3.2e-06 erg cm^-2 s^-1, with exposure of about 11% of the LR over the time interval (T0; T0 + 5 s); - from 3.1e-07 to 2.3e-06 erg cm^-2 s^-1, with exposure of about 11% of the LR over the time interval (T0; T0 + 10 s); - from 1.1e-07 to 1.6e-06 erg cm^-2 s^-1, with exposure of about 21% of the LR over the time interval (T0; T0 + 100 s). These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.