TITLE:   GCN CIRCULAR
NUMBER:  20864
SUBJECT: LIGO/Virgo G277583: AGILE GRID observations
DATE:    17/03/14 04:50:56 GMT
FROM:    Francesco Verrecchia at ASDC, INAF-OAR  <verrecchia@asdc.asi.it>

G. Minervini (INAF/IAPS), F. Verrecchia (ASDC and INAF/OAR), M. Cardillo
(INAF/IAPS), G. Piano (INAF/IAPS), C. Pittori (ASDC), M. Tavani (INAF/IAPS,
and Univ. Roma Tor Vergata), A. Bulgarelli, 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 event G277583 we performed an analysis of the
AGILE Gamma-Ray Imaging Detector (GRID) data on different timescales.

On LIGO trigger time (T0 = 2017-03-13 22:40:09.593 UT), the GRID exposure
covered about 35% of the LIGO localization region that was observed with
off-axis angles between 35 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 typical values of
3-sigma upper limits obtained within the accessible G277583  
localization region
are reported below:
4.0e-06 erg cm^-2 s^-1 for integration time of 2s,
2.7e-07 erg cm^-2 s^-1 for integration time of 20s,
7.0e-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.