Exploring the uncharted Universe with Gravitational Waves

Every time that we have looked further into the Universe, we have found fascinating surprises. Most notably, we observe that an omnipresent dark energy drives the Universe to expand ever faster, and that its large-scale structures hold together only because of an invisible dark matter.

We do not fully understand how cosmic structures form, and even if our laws of gravity are valid at all scales. Gravitational waves (GWs) – ripples in space and time produced by extreme gravitational systems in the cosmos such as binary black holes – offer a unique opportunity to answer these fundamental open questions. In this talk we will venture into uncharted regions of the Universe and explore how present and future GW observations can test the standard cosmological model.

In particular, I will discuss how the population of compact binaries can be used to constrain the expansion rate of the Universe at high-redshift, and how lensed GWs can probe dark matter substructures and shed light on the origin of the observed binary back holes.