[vsnet-grb-info 22283] LIGO/Virgo S190503bf: AGILE-GRID Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24382
SUBJECT: LIGO/Virgo S190503bf: AGILE-GRID Observations
DATE:    19/05/03 22:24:06 GMT
FROM:    Giovanni Piano at INAF-IAPS  <giovanni.piano at inaf.it>

G. Piano, A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor
Vergata), F. Verrecchia (SSDC, and INAF/OAR), M. Cardillo, C. Casentini
(INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli,
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 S190503bf at T0 = 2019-05-03
18:54:04.294 (UT), a preliminary analysis of the AGILE Gamma-Ray Imaging
Detector (GRID) exposure shows that the S190503bf 90% c.l. localization
region (LR) was almost completely occulted by the Earth at T0. We performed
a preliminary analysis at different timescales; values of 3-sigma upper
limits (UL) in the energy range 50 MeV - 50 GeV are:

(1) around 5.7e-7 erg cm^-2 s^-1 for an integration time of 5s, between T0
and T0+5s, with the GRID exposure covering nearly 4% of the LR, observed at
off-axis angles between 10 and 15 deg.

(2) around 2.8e-7 erg cm^-2 s^-1 for an integration time of 10s, between T0
and T0+10s, with the GRID exposure covering nearly 4% of the LR, observed
at off-axis angles between 10 and 15 deg.

(3) around 5.5e-8 erg cm^-2 s^-1 for an integration time of 100s, between
T0 and T0+100s, with the GRID exposure covering nearly 4% of the LR,
observed at off-axis angles between 10 and 30 deg.

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