Constraints on Non-Flat Starobinsky f(R) Dark Energy Model.

Chao-Qiang Geng,Yan-Ting Hsu,Jhih-Rong Lu

doi:10.3390/e23101320

Abstract

We study the viable Starobinsky dark energy model in spatially non-flat FLRW backgrounds, where with and representing the characteristic curvature scale and model parameter, respectively. We modify CAMB and CosmoMC packages with the recent observational data to constrain Starobinsky gravity and the density parameter of curvature . In particular, we find the model and density parameters to be at 68% C.L. and at 95% C.L., respectively. The best fitting result shows that , indicating that the viable gravity model is consistent with CDM when is set as a free parameter. We also evaluate the values of AIC, BIC and DIC for the best fitting results of and CDM models in the non-flat universe.

Highlights

It is known that cosmological observations, such as Supernova type Ia [1,2], Planck [3,4,5,6], and BAO [7], have provided strong evidence that our current universe is accelerating.Among the numerous attempts to describe this late time accelerating epoch of the universe, ΛCDM is the most successful and simplest one
We have investigated the evolutions of the normalized effective dark energy density ρ DE /ρ0DE and equation of state w DE for the Starobinsky f ( R) model in a non-flat universe
We have shown that the Starobinsky f ( R) model in the closed universe contributes to a larger dark energy density and faster evolved dark energy equation of state

Summary

Introduction

It is known that cosmological observations, such as Supernova type Ia [1,2], Planck [3,4,5,6], and BAO [7], have provided strong evidence that our current universe is accelerating. Among the numerous attempts to describe this late time accelerating epoch of the universe, ΛCDM is the most successful and simplest one. It still confronts some unsolved issues, such as the cosmological constant (CC) problem [8]. This motivates us to investigate whether the universe is a spatially curved one if we assume a model from modified gravity rather than ΛCDM. One is able to rewrite Equation (6) in the following form, [28,32,33,34]

Numerical Results

Cosmological Evolutions

Global Fitting Results

Conclusions