Abstract
The Euclid satellite, launched in July 2023 by the European Space Agency, will observe a large part of the sky for six years, and identify more than ten billion galaxies at different epochs. It will use several tools, such as gravitational lenses, baryonic acoustic oscillations, the growth rate of structures, galaxy clusters and space-redshift distortions, to lift the veil on the dark sector of the Universe. Several complementary experiments will follow : the Vera Rubin telescope in Chile, or the SKA, which will use similar tools, with other targets. SKA will use radio sources, and the HI-21cm line, targets different from Euclid's visible and infrared wavelengths. Inflation theory could be confirmed by the detection of primordial gravitational waves, either in the cosmological background and B-mode perturbations, with the ratio of tensor/scalar perturbations, or by the pulsar array with SKA.
