A comparison of effective field theory models of redshift space galaxy power spectra for DESI 2024 and future surveys

TL;DR

This study compares various effective field theory models for galaxy power spectra in redshift space, validating their consistency and applicability for DESI's upcoming data releases using mock simulations.

Contribution

It provides a detailed, apples-to-apples comparison of EFT models for redshift space galaxy power spectra, establishing their reliability for DESI analyses.

Findings

Models behave similarly and produce consistent constraints.

Models agree within the applicable scale range of 1-loop perturbation theory.

No systematic errors found in the models for the tested volume.

Abstract

In preparation for the next generation of galaxy redshift surveys, and in particular the year-one data release from the Dark Energy Spectroscopic Instrument (DESI), we investigate the consistency of a variety of effective field theory models that describe the galaxy-galaxy power spectra in redshift space into the quasi-linear regime using 1-loop perturbation theory. These models are employed in the pipelines \texttt{velocileptors}, \texttt{PyBird}, and \texttt{Folps$\nu$}. While these models have been validated independently, a detailed comparison with consistent choices has not been attempted. After briefly discussing the theoretical differences between the models we describe how to provide a more apples-to-apples comparison between them. We present the results of fitting mock spectra from the \texttt{AbacusSummit} suite of N-body simulations provided in three redshift bins to mimic the types of dark time tracers targeted by the DESI survey. We show that the theories behave similarly and give consistent constraints in both the forward-modeling and ShapeFit compressed fitting approaches. We additionally generate (noiseless) synthetic data from each pipeline to be fit by the others, varying the scale cuts in order to show that the models agree within the range of scales for which we expect 1-loop perturbation theory to be applicable. This work lays the foundation of Full-Shape analysis with DESI Y1 galaxy samples where in the tests we performed, we found no systematic error associated with the modeling of the galaxy redshift space power spectrum for this volume.