Galaxy shape statistics in the effective field theory

Understand

Intrinsic galaxy alignments yield an important contribution to the observed statistics of galaxy shapes.

• The general bias expansion for galaxy sizes and shapes in three dimensions has been recently described by Vlah, Chisari \& Schmidt using the general perturbative effective field theory (EFT) framework, in analogy to the clustering of galaxies.
• In this work, we present a formalism that uses the properties of spherical tensors to project galaxy shapes onto the observed sky in the flat-sky approximation and compute the two-point functions at next-to-leading order as well as the leading-order three-point functions of galaxy shapes and number counts.
• The resulting expressions are given in forms that are convenient for efficient numerical implementation.