Cosmological constraints on the Hu-Sawicki modified gravity scenario

TL;DR

This paper evaluates the Hu-Sawicki f(R) modified gravity model against recent cosmological observations, finding current data insufficient to tightly constrain its parameters and discussing the influence of background assumptions.

Contribution

It provides a comprehensive analysis of the Hu-Sawicki model's viability and explores the limitations of current observational data in constraining modified gravity theories.

Findings

Current observational data cannot tightly constrain the model parameters.

The model produces a viable cosmology with matter dominance and late-time acceleration.

Background assumptions significantly impact parameter inference.

Abstract

In this paper we place new constraints on a f(R) modified gravity model recently proposed by Hu and Sawicki. After checking that the Hu and Sawicki model produces a viable cosmology, i.e. a matter dominated epoch followed by a late-time acceleration, we constrain some of its parameters by using recent observations from the UNION compilation of luminosity distances of Supernovae type Ia, including complementary information from Baryonic Acoustic Oscillations, Hubble expansion, and age data. We found that the data considered is unable to place significant constraints on the model parameters and we discuss the impact of a different assumption of the background model in cosmic parameters inference.