(method of comparing observed galaxies with cosmology models)
Halo abundance matching (HAM) is a method of comparing
observation and theory regarding galaxies and their
dark matter halos. Cosmological models models and simulations
yield a certain mass distribution of halos and galaxy
surveys yield a luminosity distribution of galaxies.
The distributions may show a correspondence suggesting
a relation between halo mass and its galaxy's luminosity,
or alternately, such a correspondence can serve as a plausibility
test of some dark matter theory or of some galaxy observations.