[vsnet-grb-info 22505] LIGO-Virgo S190519bj: AGILE GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24604
SUBJECT: LIGO-Virgo S190519bj: AGILE GRID observations
DATE:    19/05/19 19:36:35 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia at ssdc.asi.it>

F. Verrecchia, F. Lucarelli (SSDC, and INAF-OAR), M. Tavani (INAF/IAPS,
and Univ. Roma Tor Vergata), M. Cardillo (INAF/IAPS), C. Pittori (SSDC, and
INAF-OAR),  C. Casentini, G. Piano A. Ursi (INAF/IAPS), 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 S190519bj at T0 = 2019-05-19 15:35:44.40
UTC (GCN #24598) a preliminary analysis of the AGILE exposure at T0 showed
that about 70% of the S190517h 90% c.l. localization region (LR) was exposed
by the Gamma-Ray Imaging Detector (GRID) at off-axis angles between 20 and
70 deg.

We performed an analysis of the GRID data in the energy range 50 MeV - 10 GeV
over three time intervals before and after T0, where good exposure of
the S190519bj 90% c.l. LR was available.

The following preliminary GRID 3-sigma upper limit (UL) values are obtained
over a large area of the exposed LR:

(T0-2s; T0+2s ): from 7.9e-07 to 3.4e-06 erg cm^-2 s^-1;

(T0; T0+10s ): from 3.1e-07 to 1.3e-06 erg cm^-2 s^-1;

(T0; T0+100s): from 3.1e-08 to 9.5e-08 erg cm^-2 s^-1.

An image of the AGILE-GRID 100s exposure near T0 is available at the site
https://tools.ssdc.asi.it/ImgView/Agile/S190519bj_T0_d100s_fv70a75E50d11

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