Halo occupation distribution

The halo occupation distribution (HOD) is a parameter of the halo model of galaxy clustering.^[1] The halo model provides one view of the large scale structure of the universe as clumps of dark matter, while the HOD provides a view of how galactic matter is distributed within each of the dark matter clumps.^[2] The HOD is used to describe three related properties of the halo model: the probability distribution relating the mass of a dark matter halo to the number of galaxies that form within that halo; the distribution in space of galactic matter within a dark matter halo; the distribution of velocities of galactic matter relative to dark matter within a dark matter halo.^[3]

See also

• Dark matter
• Large-scale structure of the cosmos
• Galaxy formation and evolution