TITLE: GCN CIRCULAR NUMBER: 21526 SUBJECT: LIGO/Virgo G298048: AGILE GRID observations DATE: 17/08/17 22:22:43 GMT FROM: Francesco Verrecchia at ASDC, INAF-OAR G. Piano (INAF/IAPS), F. Verrecchia (SSDC and INAF/OAR), M. Pilia (INAF/OA-Cagliari), M. Cardillo (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Bulgarelli (INAF/IASF-Bo), C. Pittori (SSDC and INAF/OAR), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Ursi, G. Minervini, A. Argan, Y. Evangelista (INAF/IAPS), F. Lucarelli (SSDC and INAF/OAR), N. Parmiggiani, A. Zoli, V. Fioretti, F. Fuschino (INAF/IASF-Bo), A. Trois (INAF/OA-Cagliari) M. Marisaldi (INAF/IASF-Bo and Bergen University), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW trigger event G298048 at T0 = 2017-08-17 12:41:04.446 UTC (GCN #21505) and the Fermi-GBM trigger event 170817.529 at T1 = 12:41:06.470 UTC (GCN #21506), we performed an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different timescales. On Fermi-GBM trigger time (T1) the GRID exposure covered nearly 10% of the Fermi-GBM 3-sigma localization region, observed at off-axis angles between 15 and 55 deg. Due to Earth occultation the GRID field of view did not cover the new revised HLV G298048 90% localization region (GCN #21513). An analysis of the data in the energy range 50 MeV - 10 GeV was performed on timescales from 2 to 100 sec centered at T1. Preliminary values of 3-sigma upper limits (UL) obtained within the accessible Fermi-GBM 3-sigma localization region are reported below: from 1.4e-06 to 2.2e-06 erg cm^-2 s^-1 for integration time of 2s from 1.4e-07 to 6.6e-07 erg cm^-2 s^-1 for integration time of 20s from 3.2e-08 to 8.8e-08 erg cm^-2 s^-1 for integration time of 100s These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.