[vsnet-grb-info 24349] LIGO/Virgo S191215w: upper limits from AGILE-GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26448
SUBJECT: LIGO/Virgo S191215w: upper limits from AGILE-GRID observations
DATE:    19/12/16 09:09:55 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia at ssdc.asi.it>

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

In response to the LIGO-Virgo GW event S191215w at T0 = 2019-12-15
22:30:52.333 UTC a preliminary analysis of the AGILE exposure at T0
shows that the Gamma-Ray Imaging Detector (GRID) exposure covered less
than 10% of the 90% c.l. localization region (LR) (35% 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 over time intervals before and after T0, where good exposure of
the S191215w 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 2.0e-07 to 9.4e-07 erg cm^-2 s^-1, with exposure of about 45% of
the LR over the time interval ( T0 + 100s ; T0 + 200s );

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