TITLE:   GCN CIRCULAR
NUMBER:  20690
SUBJECT: LIGO/VIRGO G274296: AGILE-GRID preliminary analysis
DATE:    17/02/18 01:21:46 GMT
FROM:    Francesco Verrecchia at ASDC, INAF-OAR  <verrecchia@asdc.asi.it>

F. Verrecchia (ASDC and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor
Vergata), A. Bulgarelli, A. Zoli , N. Parmiggiani (INAF/IASF-Bo), C. Pittori
(ASDC and INAF/OAR), I. Donnarumma, P. Munar-Adrover, G. Piano (INAF/IAPS), F.
Lucarelli (ASDC and INAF/OAR), A. Giuliani (INAF/IASF-Mi), M. Cardillo
(INAF/OA-Arcetri and INAF/IAPS), F. Longo (Univ. Trieste and INFN Trieste),
A. Ursi (INAF/IAPS), F. Fuschino (INAF/IASF-Bo), Y. Evangelista (INAF/IAPS),
M. Marisaldi (INAF/IASF-Bo and Bergen University)(INAF/IAPS), A. Argan, G.
Minervini (INAF/IAPS), M. Pilia, A. Trois (INAF/OA-Cagliari), V. Fioretti
(INAF/IASF-Bo), report on behalf of the AGILE Team:

In response to the LIGO/Virgo GW trigger G274296 (GCN #20689) we performed an
analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different
timescales. On LIGO trigger time (T0= 2017-02-17 06:05:55.050 UT) the GRID
exposure covered about 35% of the LIGO localization region that was observed
with off-axis angles between 10 and 70 deg.

An analysis of the data in the energy range 30 MeV - 10 GeV was performed on
timescales from 2 to 100 sec centered at T0. Preliminary values of 3-sigma
upper limits obtained within the accessible G274296 localization region are
reported below:

1.3e-06 erg cm^-2 s^-1 for integration time of 2s,
3.0e-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.