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GCN Circular 21526

LIGO/Virgo G298048: AGILE GRID observations
2017-08-17T22:22:43Z (7 years ago)
Francesco Verrecchia at ASDC, INAF-OAR <>
G. Piano (INAF/IAPS), F. Verrecchia (SSDC and INAF/OAR), M. Pilia
(INAF/OA-Cagliari), M. Cardillo (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ.
Roma Tor Vergata), A. Bulgarelli (INAF/IASF-Bo), C. Pittori (SSDC and
INAF/OAR), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste),
A. Ursi, G. Minervini, A. Argan, Y. Evangelista (INAF/IAPS), F. Lucarelli
(SSDC and INAF/OAR),  N. Parmiggiani, A. Zoli, V. Fioretti, F. Fuschino
(INAF/IASF-Bo), A. Trois (INAF/OA-Cagliari) M. Marisaldi (INAF/IASF-Bo and
Bergen University), A. Giuliani (INAF/IASF-Mi), report on behalf of the
In response to the LIGO/Virgo GW trigger event G298048 at T0 = 2017-08-17
12:41:04.446 UTC (GCN #21505) and the Fermi-GBM trigger event 170817.529
at T1 = 12:41:06.470 UTC (GCN #21506), we performed an analysis of the
AGILE Gamma-Ray Imaging Detector (GRID) data on different  timescales. On
Fermi-GBM trigger time (T1) the GRID exposure covered nearly 10% of the
Fermi-GBM 3-sigma localization region, observed at off-axis angles between
15 and 55 deg.

Due to Earth occultation the GRID field of view did not cover the new revised
HLV G298048 90% localization region (GCN #21513).

An analysis of the data in the energy range 50 MeV - 10 GeV was performed
on timescales from 2 to 100 sec centered at T1.
Preliminary values of 3-sigma upper limits (UL) obtained within the
accessible Fermi-GBM 3-sigma localization region are reported below:

from 1.4e-06 to 2.2e-06 erg cm^-2 s^-1 for integration time of 2s
from 1.4e-07 to 6.6e-07 erg cm^-2 s^-1 for integration time of 20s
from 3.2e-08 to 8.8e-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.
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