Correlation function (astronomy)

A correlation function is a function that describes the distribution of galaxies in the universe. Given a galaxy in a location, the correlation function describes the probability that another galaxy will be found at a given radius away. In effect, it is a lumpiness factor.

The correlation function is important for theoretical models of cosmology because it provides a means of testing models which assume different things about the contents of the universe. Computer models which calculate the formation of galaxies seem to favor cold dark matter as the model with the most support.