Abstract: | According to the LCDM concordance cosmology, our Universe is dominated by dark matter and dark energy, and underwent a phase of inflation shortly after the Big Bang. Galaxies are believed to reside in massive haloes of dark mater, which have formed out of quantum fluctuations in this inflaton field. After a brief introduction of galaxy formation in a LCDM cosmology, I discuss how we may test our concordance cosmology using the clustering and gravitational lensing properties of the galaxy population as a whole. I will introduce the Conditional Luminosity Function (CLF), which is a powerful tool to describe halo occupation statistics, the statistical description of how galaxies of different properties are distributed over dark matter halos of different mass. I show that the CLF can be constrained using either galaxy clustering or galaxy-galaxy lensing, and that a combination of these two data sets allows one to put tight constraints on cosmological parameters. |