Galaxy shape statistics in the effective field theory

Zvonimir Vlah, Nora Elisa Chisari, Fabian Schmidt

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

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. For a source redshift distribution typical of Stage IV surveys, we find that nonlinear intrinsic alignment contributions to galaxy shape correlations become relevant at angular wavenumbers l ⪆ 100.

Original languageEnglish
Article number061
Pages (from-to)1-33
JournalJournal of Cosmology and Astroparticle Physics
Volume2021
Issue number5
DOIs
Publication statusPublished - May 2021

Keywords

  • galaxy surveys
  • gravitational lensing
  • power spectrum
  • weak gravitational lensing

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