[vsnet-grb-info 25296] LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27396
SUBJECT: LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
DATE:    20/03/17 08:53:04 GMT
FROM:    Maura Pillia at INAF  <maura.pilia at inaf.it>

M. Pilia (INAF/OA-Cagliari), V. Fioretti (INAF/OAS-Bologna), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G.
Piano, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC,
and INAF/OAR), A. Bulgarelli, 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 S200316bj at T0 = 2020-03-16
21:57:56.157 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) (50% 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
S200316bj 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 1.1e-07 to 3.5e-06 erg cm^-2 s^-1, with exposure of about 50% 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.