GCN Circular 21482
Subject
LIGO/Virgo G297595: AGILE GRID observations
Date
2017-08-14T19:21:29Z (8 years ago)
From
Francesco Verrecchia at ASDC, INAF-OAR <verrecchia@asdc.asi.it>
F. Longo (Univ. Trieste and INFN Trieste), F. Verrecchia (SSDC and INAF/OAR),
G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), C.Pittori (SSDC and INAF/OAR),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Ursi, M. Cardillo, A.
Giuliani (INAF/IASF-Mi), A. Bulgarelli, N. Parmiggiani, A.Zoli, V.Fioretti
(INAF/IASF-Bo), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F. Lucarelli
(ASDC and INAF/OAR), G. Minervini (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 G297595 (GCN #21474), we performed
an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different
timescales. On LIGO/VIRGO trigger time (T0=2017-08-14 10:30:43.527 UTC) the
GRID exposure has no coverage of the LIGO/VIRGO localization region (LR) due
to Earth occultation, from bayestar.fits.gz skymap in the GraceDB.
Data analysis in the energy range 50 MeV - 10 GeV was performed only at times
when the source region was not occulted by the Earth, from T0+500 to T0+600 sec,
when the AGILE-GRID exposure partially covered the LR (about 70% of it, observed
at off-axis angles between 0 and 42 deg).
Preliminary values of 3-sigma upper limits (UL) obtained within the
accessible G297595 LR are from 3.1e-08 to 3.9e-08 erg cm^2 s^-1.
These ULs apply to a large fraction of the GRID-exposed LIGO LR.
These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.