The Dependence of Galaxy Formation on Cosmological Parameters: Can we distinguish the WMAP1 and WMAP3 Parameter Sets?

Understand

We combine N-body simulations of structure growth with physical modelling of galaxy evolution to investigate whether the shift in cosmological parameters between the 1-year and 3-year results from the Wilkinson Microwave Anisotropy Probe affects predictions for the galaxy population.

• Structure formation is significantly delayed in the WMAP3 cosmology, because the initial matter fluctuation amplitude is lower on the relevant scales.
• The decrease in dark matter clustering strength is, however, almost entirely offset by an increase in halo bias, so predictions for galaxy clustering are barely altered.
• In both cosmologies several combinations of physical parameters can reproduce observed, low-redshift galaxy properties; the star formation, supernova feedback and AGN feedback efficiencies can be played off against each other to give similar results.