GCN Circular 20770

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

In response to the LIGO/Virgo GW trigger G275697 we performed an analysis
of the AGILE Gamma-Ray Imaging Detector (GRID) data on different timescales.
On LIGO trigger time (T0= 2017-02-27 18:57:31.375 UT) the GRID exposure
covered about 50% of the LIGO localization region that was observed with
off-axis angles between 40 and 70 deg, approximately.
An analysis of the data in the energy range 50 MeV - 10 GeV was performed
on timescales from 2 to 100 sec centered at T0. Preliminary values of minimal
3-sigma upper limits obtained within the accessible G275697 localization
region are reported below:

9.8e-07 erg cm^-2 s^-1 for integration time of 2s,
1.7e-07 erg cm^-2 s^-1 for integration time of 20s,
3.9e-08 erg cm^-2 s^-1 for integration time of 100s.

These ULs apply to a large fraction of the GRID-exposed LIGO  
localization region.

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