A Simulation of Galaxy Formation and Clustering

We discuss early results from the first N-body/hydrodynamical simulation to resolve the formation of galaxies in a volume large enough for their clustering properties to be reliably determined. The simulation follows the formation of galaxies by gas cooling within dark halos of mass a few times 1011 M☉ and above, in a flat cold dark matter universe with a positive cosmological constant. Over 2200 galaxies form in our simulated volume of (100 Mpc)3. Assigning luminosities to the model galaxies using a spectral population synthesis model results in a K-band luminosity function in excellent agreement with observations. The two-point correlation function of galaxies in the simulation evolves very little since z = 3, and it has a shape close to a power law over 4 orders of magnitude in amplitude. At the present day, the galaxy correlation function in the simulation is antibiased relative to the mass on small scales and unbiased on large scales. It provides a reasonable match to observations.