The abundance and clustering of dark haloes in the standard ΛCDM cosmogony

Much evidence suggests that we live in a flat Cold Dark Matter universe with a cosmological constant. Accurate analytic formulae are now available for many properties of the dark halo population in such a Universe. Assuming current “concordance” values for the cosmological parameters, we plot halo abundance against redshift as a function of halo mass, of halo temperature, of the fraction of cosmic matter in haloes, of halo clustering strength, and of the clustering strength of the z = 0 descendants of high redshift haloes. These plots are useful for understanding how nonlinear structure grows in the model. They demonstrate a number of properties which may seem surprising, for example: 10 M⊙ haloes are as abundant at z = 20 as L∗ galaxies are today; 10K haloes are equally abundant at z = 8 and at z = 0; 10% of all matter is currently in haloes hotter than 1 keV, while more than half is in haloes too cool to trap photo-ionized gas; 1% of all matter at z = 15 is in haloes hot enough to ionise hydrogen; haloes of given mass or temperature are more clustered at higher redshift; haloes with the abundance of present-day L∗ galaxies are equally clustered at all z < 20; the metals produced by star-formation at z > 10 are more clustered at z = 0 than are L∗ galaxies.