The Effective Field Theory of Large-Scale Structure and Multi-tracer II: redshift space and realistic tracers

TL;DR

This paper extends the multi-tracer formalism within the effective field theory of large-scale structure to redshift space, demonstrating improved parameter constraints and reduced degeneracies using realistic galaxy catalogs from simulations.

Contribution

It introduces a redshift space multi-tracer analysis with realistic tracers, showing significant improvements in cosmological parameter estimation over single-tracer methods.

Findings

MT error bars are ~50% smaller than ST for key parameters.

Cosmological and bias coefficients are less degenerate in MT.

MT with perturbation theory effectively captures mildly non-linear scales.

Abstract

We extend the multi-tracer (MT) formalism of the effective field theory of large-scale structure to redshift space, comparing the results of MT to a single-tracer analysis when extracting cosmological parameters from simulations. We used a sub-halo abundance matching method to obtain more realistic multi-tracer galaxy catalogs constructed from N-body simulations. Considering different values for the sample shot noise and volume, we show that the MT error bars on $A_s$, $\omega_{\rm cdm}$, and $h$ in a full-shape analysis are approximately $50\%$ smaller relative to ST. We find that cosmological and bias coefficients from MT are less degenerate, indicating that the MT parameter basis is more orthogonal. We conclude that using MT combined with perturbation theory is a robust and competitive way to accommodate the information present in the mildly non-linear scales.