DIPC International Physics Colloquia (DIPC)

Thursday 23.03.2023 16:00

A conclusive test of the cold dark matter model

Carlos S. Frenk

Institute for Computational Cosmology Physics Dept, Durham University, UK

The "Lambda cold dark matter" (LCDM) cosmological model is one of the great achievements in Physics of the past thirty years. Theoretical predictions formulated in the 1980s turned out to agree remarkably well with measurements, performed decades later, of the galaxy distribution and the temperature structure of the cosmic microwave background radiation. Yet, these successes do not inform us directly about the nature of the dark matter. This manifests itself most clearly on subgalactic scales, including the dwarf satellite galaxies of the Milky Way and especially less massive dark matter halos, too small to have made a galaxy. Apparent contradictions between the predictions from cosmological simulations and observations have led to the perception of a "small-scale crisis" for LCDM. I will argue that this perception stems from an innapropriate application of the simulations and that, in fact, the theory is entirely consistent with available data. I will contrast the predictions of LCDM with those of the interesting alternative of warm dark matter and show how forthcoming gravitational lensing and gamma-ray data can conclusively distinguish between the two.

About the speaker: Professor Carlos S. Frenk is Director of the Institute for Computational Cosmology, Durham University's world-renowned theoretical cosmology research group. Along with collaborators from all over the world, he builds model universes in state-of-the-art supercomputers, trying to understand how the structures in our Universe evolved from simple beginnings to the complex structures composed of stars and galaxies that we see today.