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GCN Circular 21437

LIGO/Virgo G296853: AGILE GRID observations
2017-08-09T16:48:55Z (7 years ago)
Francesco Verrecchia at ASDC, INAF-OAR <>
F. Verrecchia (SSDC and INAF/OAR), G. Piano (INAF/IAPS), M. Pilia
(INAF/OA-Cagliari), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A.
Ursi (INAF/IAPS), M. Cardillo, A. Bulgarelli (INAF/IASF-Bo), C. Pittori (SSDC
and INAF/OAR), N. Parmiggiani (INAF/IASF-Bo), I. Donnarumma (ASI), A. Giuliani
(INAF/IASF-Mi), F. Lucarelli (ASDC and INAF/OAR), G. Minervini (INAF/IAPS),
F. Longo (Univ. Trieste and INFN Trieste), 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), V. Fioretti (INAF/IASF-Bo),
report on behalf of the AGILE Team:

In response to the LIGO/Virgo GW trigger G296853 (GCN #21431), we performed
an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different
timescales. On LIGO trigger time (T0=2017-08-09 08:28:21.747 UTC) the GRID
exposure covered more than the 95% of the LIGO localization region, observed
at off-axis angles between 5 and 55 deg.

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 3-sigma upper limits (UL) obtained within the
accessible G296853 localization region are reported below:

from 1.4e-06 to 6.0e-06 erg cm^-2 s^-1 for integration time of 2s
from 1.4e-07 to 5.6e-07 erg cm^-2 s^-1 for integration time of 20s
from 3.1e-08 to 8.4e-08 erg cm^-2 s^-1 for integration time of 100s

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

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