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 or the dark energy which
are the two cornerstones of the model. Furthermore, in recent years a
number of observations have suggested possible discrepancies with LCDM
both on large and small scales, such as the ``H0 and sigma-8''
tensions, the abundance of satellite galaxies in the Milky Way and the
discovery of bright galaxies at very early times by the James Webb
Space telescope. I will discuss these discrepancies and contrast the
predictions of LCDM with those of the interesting alternative of warm
dark matter. I will discuss how data from DESI, the largest galaxy
survey ever undertaken, will inform us about the model and show how
forthcoming gravitational lensing data can provide a conclusive test
of LCDM.
Einladender: Alexander Lenz / CPPS
Markus Cristinziani