TITLE: GCN CIRCULAR NUMBER: 24143 SUBJECT: AT LIGO-Virgo S190421ar: AGILE GRID observations DATE: 19/04/22 18:30:44 GMT FROM: Martina Cardillo at INAF-IAPS M. Cardillo (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, 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 S190421ar T0 = 2019-04-21 21:38:56 (UTC; GCN #24141), analysis of AGILE data shows that the satellite at T0 was in the South Atlantic Anomaly (SAA). Scientific telemetry was inhibited during the time interval (T0 -600 s; T0 + 400 s). We performed a preliminary analysis of the AGILE Gamma-Ray Imaging Detector (GRID) in the first interval available after the SAA, between T0 +450s and T0+550s. In this time interval, the GRID exposure covered nearly 55% of the LIGO/Virgo localization region (LR), observed at off-axis angles between 15 deg and 60 deg. An analysis of the data in the energy range 50 MeV - 10 GeV in this integration time was performed and preliminary 3-sigma upper limits (UL) values within the accessible LIGO/Virgo LR are: from 4.9e-8 erg cm^-2 s^-1 to 3.0e-7 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.