Session E01: Beyond Einstein Gravity: Predicting Astrophysical and Cosmological Signatures

Gravity Detectives for Fundamental Physics: Probing Strong-Field Gravity with Compact Objects and Gravitational Waves

The detections of, by now, nearly 100 gravitational wave signals originating from coalescing black hole or neutron star binaries have opened a rich discovery space for astrophysics, fundamental physics and cosmology. In particular, they enable qualitatively new tests of gravity in its most extreme, nonlinear regime. To link gravitational wave observations to extensions of general relativity, and to infer parameters of the underlying theory of gravity, we need accurate waveform models in and beyond general relativity.

In this talk, I will give an overview of recent advances in modelling compact binaries in modified theories of gravity with particular focus on numerical relativity beyond GR and I will highlight new dynamical phenomena that are absent in GR.   

Cosmological probes of gravity: the gravitational wave perspective

Our understanding of the universe stands on the validity of Einstein gravity at the largest scales. Despite its tremendous success in laboratory experiments and Solar System tests, we still lack of a precise knowledge of gravity at the cosmological regime. In this talk I will present how we can achieve this using gravitational waves (GW) from merging compact objects. In particular I will describe the main signatures of beyond Einstein theories and how they can be tested on individual GW events or performing population analyses. In order to claim any modification of gravity it is essential to account for the possible degeneracies with other astrophysical processes. I will conclude with the prospects of future next generation ground-based detectors and space antennas.