Gravitational waves (GWs) are novel signals that probe the behavior of gravity in both the strong and weak-field regimes. As these waves propagate towards us over cosmological distance, they are sensitive to the expansion rate of the Universe, the gravitational self-interactions, and the presence of cosmological fields. In this talk, I will first illustrate how we can constrain the properties of gravity and dark energy with GWs. After that, I will show that, similarly to light, GWs can be gravitationally lensed by intervening galaxies or clusters of galaxies. One important difference with light though is that the detection of GWs is sensitive to the phase of the wave, which can change due to gravitational lensing. I will discuss what this change of phase is, how it can affect observations, and how it can be used as a unique signature to help identify future GW lensed events, which will in turn open the way for even further cosmological science with GWs.

zoom link: https://univ-amu-fr.zoom.us/j/91448970216?pwd=SzhmcmRmVmpIY2l0a0JRSUpNdyszdz09