TITLE: GCN CIRCULAR NUMBER: 33894 SUBJECT: LIGO/Virgo/KAGRA S230529ay: upper limits from AGILE/MCAL DATE: 23/05/30 08:00:31 GMT FROM: Francesco Verrecchia at SSDC,INAF-OAR francesco.verrecchia@ssdc.asi.it
F. Longo (Univ. Trieste, and INFN Trieste), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Verrecchia, C. Pittori (SSDC, and INAF/OAR), M. Cardillo, C. Casentini, L. Foffano, G. Piano (INAF/IAPS), A. Ursi (ASI and INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), L. Baroncelli, A. Bulgarelli, A. Ciabattoni, A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), report on behalf of the AGILE Team:
In response to the LIGO/Virgo/KAGRA GW event S230529y at T0 = 2023-05-29 18:15:00.89 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering -/+ 15 sec from the LIGO/Virgo/KAGRA T0.
At the T0, about 60% of the S230529y 90% c.l. localization region was accessible to the AGILE/MCAL.
Three-sigma upper limits (ULs) are obtained for a 1 s integration time at different celestial positions within the accessible S230529y localization region in the energy range 0.4-1 MeV, from a minimum of 1.5E-06 erg cm^-2 to a maximum of 3.1E-06 erg cm^-2 (assuming as spectral model a single power-law with photon index 1.5).
An independent procedure based on photon counting statistics provides UL fluences in the same band, from a minimum of 1.1E-08 erg cm^-2 to a maximum of 2.1E-08 erg cm^-2.
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.