Gravity claims a central role in physics. Almost every grand challenge in astrophysics, cosmology and fundamental physics includes gravity as a key ingredient, making it a subject of strong interdisciplinarity. Black Holes (BHs) are the atoms of General Relativity (GR). They are the “simplest” astrophysical objects, yet they harbour the most remarkable predictions of GR: event horizons and singularities. Gravitational-wave (GW) astronomy – made possible by the historical detection of GWs in 2016 – will allow us to test models of BH formation, growth and evolution, as well as models of GW generation and propagation. It will provide evidence for event horizons and ergoregions, test GR itself and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to answer some of the most pressing issues in our understanding of the cosmos and the laws of Nature. The scientific prospects and exciting opportunities have potential paradigm-shifting consequences in astrophysics, cosmology, and fundamental physics.
This Action will link 3 scientific communities: one specializing in GW detection, another in BH modelling, and a third in strong-gravity tests of fundamental physics, forming a single interdisciplinary network, facilitating a common language and a framework to discuss. Building bridges between these interrelated fields will drive excellence in BH and GW research in Europe. The Action will train the next generation of leaders in the field, the very first “native” GW/multi-messenger astronomers and shall pave the way for European researchers to become global leaders in the approaching age of GW physics of high precision.