[vsnet-grb-info 24670] LIGO/Virgo S200115j: upper limits from AGILE/GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26769
SUBJECT: LIGO/Virgo S200115j: upper limits from AGILE/GRID observations
DATE:    20/01/15 11:50:13 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi at gmail.com>

A. Ursi (INAF/IAPS), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), M.
Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini,
G. Piano (INAF/IAPS), F. Lucarelli (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 S200115j at T0 = 2020-01-15
04:23:09.753 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) (46% 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 over time intervals before and after T0, where good exposure of the
S200115j 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 1.2e-07 to 3.6e-07 erg cm^-2 s^-1, with exposure of about 34% of the
LR over the time interval ( T0 - 200s ; T0 - 100s );
from 3.9e-08 to 8.7e-06 erg cm^-2 s^-1, with exposure of about 32% of the
LR over the time interval ( T0 + 200s ; T0 + 300s ).

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