The halo model for cosmology: a pedagogical review

Understand

We present a pedagogical review of the halo model, a flexible framework that can describe the distribution of matter and its tracers on non-linear scales for both conventional and exotic cosmological models.

• We start with the premise that the complex structure of the cosmic web can be described by the sum of its individual components: dark matter, gas, and galaxies, all distributed within spherical haloes with a range of masses.
• The halo properties are specified through a series of simulation-calibrated ingredients including the halo mass function, non-linear halo bias and a dark matter density profile that can additionally account for the impact of baryon feedback.
• By incorporating a model of the galaxy halo occupation distribution, the properties of central and satellite galaxies, their non-linear bias and intrinsic alignment can be predicted.