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In the wake of modern Cosmology, the work of the COSMOS team of the IP2I contributes to a better understanding of the general properties of the Universe, its energy content, its structure on large scales as well as the physical laws governing its evolution over time.

Our work is being carried out within the scope of the cosmological concordance model, the most complete model available to cosmologists. This model describes an isotropic and homogeneous Universe in accelerated expansion from an extremely dense and hot primordial state. It is the result of a progressive construction from the theory of general relativity (1915) to the discovery of the accelerated expansion of the Universe (Nobel Prize in Physics 2011) which brought cosmology into a new era, with many fundamental questions still open:

  • What is the history of the expansion of the Universe?
  • What is the nature of the “dark matter” and “dark energy” that represent about 95% of the energy content of the Universe according to the current cosmological model?
  • What is the origin of large structures in the Universe and the history of their formation?

To try to answer these questions, we use a variety of cosmological probes.

The distribution of galaxy velocities in the near Universe allows us to understand the distribution of matter in our galactic environment and to test different theories of gravity – see Cosmic Flow & Simulations (IDEX).

Thermonuclear supernovae make it possible to rigorously constrain cosmological parameters, in particular the nature of the mysterious “dark energy” that would be responsible for the acceleration of its expansion – see ERC-USNAC.

Our group is also widely involved in major international collaborations in observational cosmology, including the Euclid and LSST projects – See LSST and Euclid.

Finally, we are participating in the development of new instruments on the ground and in space with particular emphasis on near infrared detectors and slit-free spectroscopy – See Euclid.