Testing Dark Energy with Multi-Messenger Observations

We still have a considerable lack of understanding about the constituents of our Universe and, in addition, tensions are starting to arise between datasets as we reach subpercent precision constraints. In this talk, I will mention how we can use standard sirens to probe possible physics beyond the concordance LCDM model. In particular, I will show how the presence of a dynamical dark energy component can induce a time-evolving gravitational coupling, which modifies the propagation of gravitational waves, and can thus be tested with observations of compact binary mergers. I will also discuss how dynamical dark energy can bias independent constraints on the current Hubble rate set with future LIGO detections. Finally, I will clarify the role that other constraints on time-evolving gravitational couplings ---such as from Lunar Laser Ranging and Binary Pulsars--- play on the outlook of using standard sirens for testing dark energy.