[vsnet-grb-info 23096] LIGO/Virgo S190728q: no counterpart candidates in AGILE-GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25195
SUBJECT: LIGO/Virgo S190728q: no counterpart candidates in AGILE-GRID observations
DATE:    19/07/28 12:44:11 GMT
FROM:    Giovanni Piano at INAF-IAPS  <giovanni.piano at inaf.it>

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

In response to the LIGO-Virgo GW event S190728q at T0 = 2019-07-28
06:45:10.547 UTC a preliminary analysis of the AGILE exposure at T0 shows
that the Gamma-Ray Imaging Detector (GRID) exposure covered ~55% of the 90%
c.l. localization region (LR).

We performed an analysis of the GRID data in the energy range 50 MeV - 10
GeV near T0.

No candidate gamma-ray transient was detected.

The following preliminary GRID values of 3-sigma upper limits (ULs) are
obtained:

from 1.4e-06 to 4.0e-06 erg cm^-2 s^-1, with exposure of about 57% of the
LR over the time interval (T0 - 2s; T0 + 2s);
from 1.1e-06 to 3.2e-06 erg cm^-2 s^-1, with exposure of about 57% of the
LR over the time interval (T0; T0 + 5s);
from 4.6e-07 to 1.6e-06 erg cm^-2 s^-1, with exposure of about 57% of the
LR over the time interval (T0; T0 + 10s);
from 3.2e-08 to 4.4e-07 erg cm^-2 s^-1, with exposure of about 66% of the
LR over the time interval (T0; 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.