Effects of Symmetron on growth and RSD multipoles

TL;DR

This paper investigates how the Symmetron modified gravity model affects cosmic structure growth and redshift-space distortion multipoles, comparing it with other models using perturbation theory and mock data to validate the analysis pipeline.

Contribution

It introduces a scale-dependent growth analysis of the Symmetron model using 1-loop perturbation theory and validates the methodology with mock catalogs, preparing for future galaxy survey tests.

Findings

Symmetron monopole is closer to $ m extbf{ extit{ ext{Λ}}}$CDM at z=0.

Quadrupole behavior differs between MG models and ΛCDM.

MCMC analysis recovers GR limit from mock data successfully.

Abstract

In this work, we investigate the effects of the growth rate scale dependence in the Symmetron modified gravity (MG) model on cosmic structure formation and we analyze the redshift-space distortion (RSD) multipoles, comparing with the Hu-Sawicki $f(R)$ model (specifically the F6) and the standard $\Lambda$CDM model. The analysis employs a scale-dependent growth equation and utilizes the fk-PT perturbation theory approach, implemented in the FOLPS-nu code, to compute the full 1-loop power spectrum multipoles, in particular, the monopole and quadrupole ($\ell=0,2$, respectively). The results show that at redshift $z=0$, the monopole of both MG models is suppressed compared to $\Lambda$CDM, with the Symmetron being closer to the standard model, while the quadrupole presents the opposite behavior. To validate the pipeline, we use General Relativity (GR) mock catalogs (EZMocks), since suitable Symmetron simulations are not available. The main result is that the Markov Chain Monte Carlo (MCMC) analysis successfully recovers the expected GR limit (i.e., $\beta_0 \approx 0$) from the Symmetron model when applied to this mock data, confirming the viability of our methodology for cosmological inference. Then, we conclude that the pipeline is prepared to test MG models against current and near-future galaxy surveys.