Angular correlation function

The angular correlation function is a function which measures the projected clustering of galaxies, due to discrepancies between their actual and expected distributions. The function may be computed as follows: $$w(\theta)=\frac{1}{N}\frac{dP}{d\Omega}-1$$, where $$P$$ represents the conditional probability of finding a galaxy, $$\Omega$$ denotes the solid angle, and $$N$$ is the mean number density. In a homogeneous universe, the angular correlation scales with a characteristic depth.