{
  "bibcode": "2019GCN.25816....1A",
  "body": "M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite de Paris), M. Colomer (APC/Universite de Paris), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite de Paris), T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration:\n\n\nUsing on-line data from the ANTARES detector, we have performed a follow-up analysis of the\nrecently reported LIGO/Virgo S190923y event using the 90% contour of the Initial bayestar probability\nmap provided by the GW interferometers (GCN#25814 <https://gcn.gsfc.nasa.gov/gcn3/25814.gcn3>). The ANTARES visibility at the time of the\nalert, together with the 50% and 90% contours of the probability map are shown at http://antares.in2p3.fr/GW/S190923y_Initial.png <http://antares.in2p3.fr/GW/S190923y_Initial.png>.\nConsidering the location probability provided by the LIGO/Virgo collaborations, there is a\n41.7% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of\nthe alert.\n\nNo up-going muon neutrino candidate events were recorded in the ANTARES sky during a\n+/-500s time-window centered on the time 2019-09-23 12:55:59 and in the 90% contour of the S190923y\nevent. The expected number of atmospheric background events in the region visible by ANTARES is\n6.99e-04 in the +/- 500s time window. An extended search during +/- 1 hour gives no\nup-going muon neutrino coincidence. The expected number of atmospheric background events in the\nregion visible by ANTARES is 5.03e-03 in this larger time window.\n\nANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is\nprimarily sensitive to neutrinos in the TeV-PeV  energy range. At 10 TeV, the median angular\nresolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a\ncompetitive sensitivity to this position in the sky.",
  "circularId": 25816,
  "createdOn": 1569248593000,
  "email": "tpradier@km3net.de",
  "subject": "LIGO/Virgo S190923y : no neutrino counterpart candidate in ANTARES search",
  "submitter": "Thierry Pradier at ANTARES/IPHC/U of Strasbourg  <tpradier@km3net.de>",
  "eventId": "LIGO/Virgo S190923y"
}