[vsnet-grb-info 24109] LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26208
SUBJECT: LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
DATE:    19/11/09 06:57:35 GMT
FROM:    Carlotta Pittori at ASI SSDC, INAF-OAR  <carlotta.pittori at ssdc.asi.it>

V. Fioretti (INAF/OAS-Bologna), C. Pittori (SSDC, and INAF/OAR), M.
Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C.
Casentini, G. Piano, A. Ursi (INAF/IAPS), F. Lucarelli, F. Verrecchia
(SSDC, and INAF/OAR), A. Bulgarelli, 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 S191109d at T0 = 2019-11-09
01:07:17.221 UTC a preliminary analysis of the AGILE exposure at T0 shows
that the Gamma-Ray Imaging Detector (GRID) exposure covered about 25% of
the 90% c.l. localization region (LR) (0% of 90% c.l. localization region
(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 S191109d 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 7.77e-07 to 8.79e-06 erg cm^-2 s^-1, with exposure of about 26% of
the LR over the time interval ( T0 -2s ; T0 + 2s );
from 6.16e-07 to 8.61e-06 erg cm^-2 s^-1, with exposure of about 25% of
the LR over the time interval ( T0s ; T0 + 5s );
from 3.06e-07 to 7.69e-06 erg cm^-2 s^-1, with exposure of about 25% of
the LR over the time interval ( T0s ; T0 + 10s );
from 3.78e-08 to 7.69e-06 erg cm^-2 s^-1, with exposure of about 25% 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.