{
  "circularId": 33826,
  "body": "F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ.\nRoma Tor Vergata), A. Ursi (ASI), C. Pittori (SSDC, and INAF/OAR),\nM. Cardillo, C. Casentini, L. Foffano, G. Piano (INAF/IAPS), F.\nLucarelli (SSDC, and INAF/OAR), L. Baroncelli, A. Bulgarelli, A.\nCiabattoni, A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani\n(INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ.\nTrieste, and INFN Trieste), report on behalf of the AGILE Team:\n\nIn response to the LIGO/Virgo GW event S230518h at T0 = 2023-05-18\n12:59:08.167 (UT), a preliminary analysis of the AGILE minicalorimeter\n(MCAL) triggered data found no significant event candidates within\na time interval covering -/+ 2 sec from the LIGO/Virgo T0.\n\nAt the T0, about 25% of the S230518h 90% c.l. localization region\n(LR) was accessible to the AGILE/MCAL.\n\nThree-sigma upper limits (ULs) are obtained in the 0.4-1 MeV energy\nrange, for a 1 s integration time at different celestial positions\nwithin the accessible S230518h LR, from a minimum of 1.4E-06 erg\ncm^-2 to a maximum of 6.6E-06 erg cm^-2 (assuming as spectral model\na single power-law with photon index 1.5).\n\nAn independent procedure based on photon counting statistics\nprovides UL fluences in the range 0.4-1 MeV, for a 300 microseconds\nintegration time, from a minimum of 1.1E-08 erg cm^-2 to a maximum\nof 4.4E-08 erg cm^-2.\n\nWe notice the detection of a short pulse in the energy range 0.4-1.4\nMeV with S/N 5.7 at time T0+10.77 s.\n\nThe AGILE/MCAL detector is a CsI detector with a 4 pi FoV, sensitive\nin the energy range 0.4-100 MeV. Additional analysis of AGILE data\nis in progress.\n\n",
  "createdOn": 1684497244761,
  "subject": "LIGO/Virgo S230518h: AGILE/MCAL observations",
  "bibcode": "2023GCN.33826....1V",
  "submitter": "Francesco Verrecchia at SSDC,INAF-OAR <francesco.verrecchia@ssdc.asi.it>",
  "eventId": "LIGO/Virgo S230518h"
}