TITLE:   GCN CIRCULAR
NUMBER:  20769
SUBJECT: LIGO/Virgo G275697: AGILE MCAL Observations
DATE:    17/02/27 23:18:00 GMT
FROM:    Francesco Verrecchia at ASDC, INAF-OAR  <verrecchia@asdc.asi.it>

A. Ursi (INAF/IAPS), P. Munar-Adrover (INAF/IAPS), F. Verrecchia (ASDC and
INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Bulgarelli,
V. Fioretti, A. Zoli, N. Parmiggiani (INAF/IASF-Bo), C. Pittori, F. Lucarelli
(ASDC and INAF/OAR), G. Minervini, M. Cardillo, G. Piano, 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 G275697 at T0 = 2017-02-27
18:57:31.375 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 where collected about 30 sec before and 45 sec after
the LIGO T0; they show no significant transient candidate event. About 80%
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 G275697 error box and varies from a minimum of 4.7e-7 erg cm^-2 to a
maximum of 11.3 e-7 erg cm^-2, assuming as 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.