Fundamental Fields and Compact Objects: new opportunities

The celebrated detection of gravitational waves (GWs), the first observation of horizon scale structure of a black hole (BH) together with the developments in the field of numerical relativity, are allowing access to extreme (strong and dynamical) gravity configurations, both observationally and theoretically, making our time a golden epoch for studying extreme gravitational systems.In parallel, families of exotic but theoretically sound models of BHs and horizonless compact objects in the presence of new fundamental fields, or alternative theories of gravity have been constructed, to a large extent numerically. These can be submitted to computational experiments, to test their dynamics, and compared against observations, to address the issue of degeneracy in the theoretical interpretations of strong gravity data or even detect putative better fits to the data. At the meeting point between these two developments lies the promise of new fundamental physics, a deeper understanding of BHs and neutron stars, unveling the nature of dark matter and dark energy. Delivering on this promise requires a synergetic endeavour that must bring together different groups and competences. This project creates a multi-connected team with different and complementary scientific expertises - on BHs, neutron stars and exotic compact objects -, their phenomenology - GWs, lensing and astrophysical environments - and the techniques necessary to extract the latter from the former for comparison with observations, including constructing and evolving solutions of non-standard compact objects with numerical methods, building GW libraries, lensing images and performing data/Bayesian analysis and parameter estimation. The team includes members of the LIGO-Virgo-Kagra and Event Horizon Telescope collaborations, providing a direct connection to observations, and will explore deep learning frameworks to face the key challanges of model classification and data augmentation.