The Power-Law Galaxy Correlation Function
For nearly 40 years, the galaxy-galaxy correlation function has been used to characterize the distribution of galaxies on the sky. In addition, the galaxy correlation function has been recognized as very nearly power-law like despite the fact that it is measured over a wide range of scales. In particular, the galaxy correlation function has been measured on very large scales (~30 Mpc), on which density fluctuations are mild and perturbative approaches are appropriate, as well as very small scales (~0.1 Mpc), on which the evolution of the density field of the universe is quite nonlinear. Nonetheless, the correlation function is nearly a power law across that range of scales, driving many to think that something heretofore unknown must set the galaxy correlation function. In my talk, I will describe the problem posed by these observations and recent work by myself and collaborators arguing that this is simply a coincidence. Time permitting, I will also discuss some new methods for interpreting galaxy correlation functions as measured from contemporary and forthcoming galaxy surveys.