22 | 24 | The discovery of gravitational waves (GW) was one of the major milestones achieved during Enigmass1, opening up a rich science program initiated with the results obtained from the binary black hole and binary neutron star mergers detected so far by LIGO and Virgo. The binary neutron star merger GW170817 was also a spectacular and ground-breaking multi-messenger event, with its short gamma ray burst and kilonova counterparts. Multi-wavelength and multi-messenger observations are key tools to characterize GW sources, the high-energy sky, and cosmic rays, in order to address major open questions in fundamental physics, astrophysics and cosmology. Through remarkable synergies, the consortium is in a unique position to have a high-impact contribution in this line of research within Enigmass2, through experimental and theoretical activities, including strong involvement in several ESFRI projects.\\ |