Galactos: Computing the Anisotropic 3-Point Correlation Function for 2 Billion Galaxies

Understand

The nature of dark energy and the complete theory of gravity are two central questions currently facing cosmology.

• A vital tool for addressing them is the 3-point correlation function (3PCF), which probes deviations from a spatially random distribution of galaxies.
• However, the 3PCF's formidable computational expense has prevented its application to astronomical surveys comprising millions to billions of galaxies.
• We present Galactos, a high-performance implementation of a novel, O(N^2) algorithm that uses a load-balanced k-d tree and spherical harmonic expansions to compute the anisotropic 3PCF.