GCN Circular 20863

M.Cardillo (INAF/IAPS), F. Verrecchia (ASDC and INAF/OAR), G. Minervini
(INAF/IAPS), G. Piano (INAF/IAPS), A. Bulgarelli (INAF/IASF-Bo), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), C. Pittori (ASDC),  V. Fioretti,
A. Zoli, N. Parmiggiani (INAF/IASF-Bo),  F. Lucarelli (ASDC and INAF/OAR),
P. Munar-Adrover (INAF/IAPS), A. Argan, Y. Evangelista (INAF/IAPS), I.
Donnarumma (ASI), F. Fuschino, M. Marisaldi (INAF/IASF-Bo and Bergen
University), A. Giuliani (INAF/IASF-Mi), M. Pilia, A. Trois
(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 G277583 at T0 = 2017-03-13
22:40:09.593 UTC, a preliminary analysis of the AGILE-GW fast data
processing procedure found no AGILE MiniCALorimeter (MCAL) event candidates
within a time interval covering -/+ 50 sec from the LIGO T0.

Two data acquisitions were collected about 55 sec before and 30 sec after
the LIGO T0; they show no significant transient candidate event. About 40%
of the LIGO error box was observable by the AGILE MCAL. A 3-sigma UL was
computed for a 1 s integration time, on different celestial positions within
the G277583 error box and varies from a minimum of 5.5e-7 erg cm^-2 to a
maximum of 10 e-7 erg cm^-2, assuming as a spectral model a simple power
law with photon index 1.4. The AGILE-MCAL instrument is a CsI detector with
a 4-pi FoV, working in the range 0.4 - 100 MeV. Additional analysis of AGILE
data is in progress.