[vsnet-grb-info 22358] LIGO-Virgo S190510g: AGILE GRID observations

[LIGO/Virgo Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24457
SUBJECT: LIGO-Virgo S190510g: AGILE GRID observations
DATE:    19/05/10 16:27:22 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia at ssdc.asi.it>

F. Verrecchia (SSDC, and INAF-OAR), A. Ursi (INAF/IAPS),  M. Tavani 
(INAF/IAPS,
and Univ. Roma Tor Vergata), F. Lucarelli, C. Pittori (SSDC, and INAF-OAR),
M. Cardillo, C. Casentini, G. Piano (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 S190510g at T0 = 2019-05-10
02:59:39.292 UTC (GCN #24442 including an updated localization) a 
preliminary
analysis of the AGILE exposure at T0 showed that about 60% of the S190510g
90% c.l. localization region (LR) was exposed at off-axis angles between 25
and 75 deg by the Gamma-Ray Imaging Detector (GRID).

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
S190510g 90% c.l. LR was available. No candidate gamma-ray transient was 
detected.

The following preliminary GRID 3-sigma upper limit (UL) values are obtained:

(T0 - 2s; T0 + 2s): from 7.4e-07 to 1.7e-06 erg cm^-2 s^-1
(T0 - 10s; T0 + 10s): from 1.5e-07 to 3.5e-07 erg cm^-2 s^-1
(T0; T0 + 100s): from 4.2e-08 to 1.8e-07 erg cm^-2 s^-1

An image of the AGILE-GRID exposure near T0 is available at the site
https://tools.ssdc.asi.it/ImgView/Agile/S190510g_d4s_FM_UL-E50bemod8

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