GCN Circular 21066

M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (IFIC & APC), D.
  Dornic (CPPM/CNRS), A. Kouchner (APC/Universite Paris Diderot), T.
  Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES
  Collaboration:

  Using on-line data from the ANTARES detector, we have performed a
  follow-up analysis of the recently reported LIGO/Virgo G284239 event
  using the initial LIGO LIB_skymap probability map at event time (LVC
  GCN Circ. 21060
Not found
 
 
). The ANTARES visibility at the time of the alert
  together with the 90% contour of the probability map are shown
  in: https://www.cppm.in2p3.fr/~dornic/events/G284239.png <https://www.cppm.in2p3.fr/~dornic/events/G284239.png> (gwantares/
  ANT@GW). Considering the location probability provided by the LIGO
  collaboration, there is a 52% chance that the GW emitter was in the
  ANTARES field of view.

  No up-going muon neutrino candidate events were recorded within the 90%
  contour during a +/- 500s time-window centered on the G284239 event
  time. The expected number of atmospheric background events in the
  region visible by ANTARES is ~2.6e-2 in the +/- 500s time window. An
  extended search during +/- 1 hour gives no up-going neutrino
  coincidence.

  An estimate of the upper limit on the associated neutrino fluence will
  be sent in a subsequent circular.

  ANTARES, being installed in the Mediterranean Deep Sea, is the largest
  neutrino detector in the Northern Hemisphere.  It is primarily
  sensitive to astrophysical neutrinos in the TeV-PeV energy range.  At
  10 TeV, the median angular resolution for muon neutrinos is below 0.5
  degrees.  In the range 1-100 TeV, ANTARES has the best sensitivity to a
  large fraction of the Southern sky.