[vsnet-grb-info 24309] LIGO/Virgo S191213g: upper limits from AGILE-GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26408
SUBJECT: LIGO/Virgo S191213g: upper limits from AGILE-GRID observations
DATE:    19/12/13 09:03:46 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia at ssdc.asi.it>

C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, G. Piano, A. Ursi
(INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli,
V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia
(INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report
on behalf of the AGILE Team:

In response to the LIGO-Virgo GW event S191213g at T0 = 2019-12-13
04:34:08.142 UTC a preliminary analysis of the AGILE exposure at T0 shows
that the Gamma-Ray Imaging Detector (GRID) exposure covered about 11%
of the 90% c.l. localization region (LR; 36% of 90% c.l. LR is occulted by
Earth).

We performed an analysis of the GRID data in the energy range 50 MeV -
10 GeV on T0, where good exposure of the S191213g 90% c.l. LR was
available.

No candidate gamma-ray transient was detected.

The following preliminary GRID values of 3-sigma upper limit (UL) are
obtained:

from 4.0e-06 to 9.9e-06 erg cm^-2 s^-1, with exposure of about 11% of
the LR over the time interval ( T0 -2s ; T0 + 2s );
from 1.6e-06 to 9.4e-06 erg cm^-2 s^-1, with exposure of about 16% of
the LR over the time interval ( T0s ; T0 + 10s );
from 4.9e-08 to 6.3e-07 erg cm^-2 s^-1, with exposure of about 34% of
the LR over the time interval ( T0s ; T0 + 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.