Exploring Galaxy Formation Models and Cosmologies with Galaxy Clustering
  Using N-body simulations and galaxy formation models, we study the galaxy
stellar mass correlation and the two-point auto-correlation. The simulations
are run with cosmological parameters from the WMAP first, third and seven year
results, which mainly differ in the perturbation amplitude of \sigma_{8}. The
stellar mass of galaxies are determined using either a semi-analytical galaxy
formation model or a simple empirical abundance matching method. Compared to
the SDSS DR7 data at z=0 and the DEEP2 results at z=1, we find that the
predicted galaxy clusterings from the semi-analytical model are higher than the
data at small scales, regardless of the adopted cosmology. Conversely, the
abundance matching method predicts good agreement with the data at both z=0 and
z=1 for high \sigma_8 cosmologies (WMAP1 & WMAP7), but the predictions from a
low \sigma_8 cosmology (WMAP3) are significantly lower than the data at z=0. We
find that the excess clustering at small-scales in the semi-analytical model
mainly arises from satellites in massive haloes, indicating that either the
star formation is too efficient in low-mass haloes or tidal stripping is too
inefficient at high redshift. Our results show that galaxy clustering is
strongly affected by the models for galaxy formation, thus can be used to
constrain the baryonic physics. The weak dependence of galaxy clustering on
cosmological parameters makes it difficult to constrain the WMAP1 and WMAP7
cosmologies.
