Difference: GCNCIRCULAR21785 ( vs. 1)

F. Verrecchia (SSDC and INAF/OAR), M. Cardillo (INAF/IAPS), A. Bulgarelli (INAF/IASF-Bo), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), I. Donnarumma (ASI), C. Pittori (SSDC and INAF/OAR), 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:

We performed a dedicated analysis of AGILE Gamma-Ray Imaging Detector (GRID) data in response to the detection on 2017-08-26 by Chandra of an X-ray transient (Troja et al., LVC GCN 21765). This source is coincident with the optical/IR transient SSS17a (Coulter et al., LVC GCN 21529) possibly associated with GW170817A.

GRID data analysis covering the SSS17a position was performed in the energy range 50 MeV - 10 GeV with integration times from 1 to 3 days centered at T0+9 days. Preliminary values of 2-sigma upper limits (UL) are reported below:

3.0e-10 erg cm^-2 s^-1 for a 1-day integration time (from 26 August 00:00 UT to 27 August 00:00 UT);

1.9e-10 erg cm^-2 s^-1 for a 2-day integration time (from 26 August 00:00 UT to 28 August 00:00 UT);

1.3e-10 erg cm^-2 s^-1 for a 3-day integration time (from 25 August 00:00 UT to 28 August 00:00 UT).

These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.

-- ThomasKupfer - 02 Sep 2017