[vsnet-grb-info 22537] LIGO/Virgo S190521r: No counterpart candidate in AGILE-MCAL observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24636
SUBJECT: LIGO/Virgo S190521r: No counterpart candidate in AGILE-MCAL observations
DATE:    19/05/21 09:45:11 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini at inaf.it>

C.Casentini (INAF/IAPS), F.Verrecchia (SSDC, and INAF/OAR), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M.Cardillo, G.Piano, A.Ursi
(INAF/IAPS), F.Lucarelli, C. Pittori (SSDC, and INAF/OAR), 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 S190521r at T0 = 2019-05-21T07:43:59
(UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered
data found no event candidate within a time interval covering +/- 15 sec
from the LIGO/Virgo T0.

Three-sigma upper limits (ULs) are obtained for a 1 s integration time at
different celestial positions within the accessible 90% c.l. localization
region (LR) of S190521r (almost 80% of the LR), from a minimum of 1.6E-06
erg cm^-2 to a maximum of 7.6E-06 erg cm^-2 (assuming as spectral model a
single power law with photon index 1.5). The average off-axis angle is
about 70 degrees.

The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the
energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.