Follow-up of O3 gravitational wave events with neutrinos in ANTARES and KM3NeT telescopes

Astrophysical neutrinos may be produced during the coalescence of compact objects, in particular those involving neutron stars. Such mergers have been identified through gravitational wave detections by the LIGO and Virgo collaborations and reported in published catalogs. The ANTARES and KM3NeT deep-sea neutrino telescopes are sensitive to neutrino interactions in a wide range of energies, from MeV to PeV. The under-construction KM3NeT telescope covers this energy range with two detectors: ORCA for neutrinos below the TeV and ARCA for TeV–PeV, extending the capabilities of the now-decommissioned ANTARES telescope. This contribution presents the search for neutrinos in time and space correlation with the gravitational wave signals reported during the Third Observing Run of LIGO/Virgo. The ANTARES analysis uses track-like and shower-like events originating from high-energy neutrino interactions. It focuses on a ±500-second time window centered on the time of the merger given by the gravitational wave signal. Two KM3NeT studies are carried out using the data from the partial KM3NeT/ORCA detector: a search for upgoing tracks induced by GeV-TeV neutrinos in the same window as above; and a search for a MeV neutrino signal in a shorter 2-second time window. The results are provided in terms of upper limits on the incoming neutrino flux in the various energy ranges and the total isotropic energies emitted in neutrinos. High-energy observations are also stacked to probe the typical neutrino emission from different populations of mergers. The complementarity of ANTARES and KM3NeT results is also explored.