Cosmological constraints on ghost dark energy in the Brans–Dicke theory by using MCMC approach

Hamzeh Alavirad,Ahmad Sheykhi

doi:10.1016/j.physletb.2014.05.023

Hamzeh Alavirad, Ahmad Sheykhi

Open Access

https://doi.org/10.1016/j.physletb.2014.05.023

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Abstract

By using a Markov Chain Monte Carlo simulation, we investigate cosmological constraints on the ghost dark energy (GDE) model in the framework of the Brans–Dicke (BD) theory. A combination of the latest observational data of the cosmic microwave background radiation data from seven-year WMAP, the baryon acoustic oscillation data form the SDSS, the supernovae type Ia data from the Union2 and the X-ray gas mass fraction data from the Chandra X-ray observations of the largest relaxed galaxy clusters are used to perform constraints on GDE in the BD cosmology. In this paper, we consider both flat and non-flat universes together with interaction between dark matter and dark energy. The main cosmological parameters are obtained as: Ωbh2=0.0223−0.0013+0.0016, Ωch2=0.1149−0.0104+0.0088 and Ωk=0.0005−0.0073+0.0025. In addition, the Brans–Dicke parameter ω is estimated as 1/ω≃0.002.

Highlights

Accelerating expansion of the Universe [1,2] can be explained either by a missing energy component usually called “dark energy” (DE) with an exotic equation of state, or by modifying the underlying theory of gravity on large scales
At the end of this section we should assert that the data points parameters of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) data sets which we use in this paper are the best fit values for ΛCDM and the error estimates are based on the ΛCDM model
The positive best fit value of parameter ξ describe a conversion of dark matter to dark energy both in flat and non-flat universes, in 1-σ CL, an inverse conversion is possible as well

Summary

Introduction

Accelerating expansion of the Universe [1,2] can be explained either by a missing energy component usually called “dark energy” (DE) with an exotic equation of state, or by modifying the underlying theory of gravity on large scales. It is of great interest to see whether the GDE model in the framework of the BD theory is compatible with observational data or not. 2. Interacting ghost dark energy in the Brans–Dicke theory in a non-flat universe. Let us first review the formalism of the interacting GDE in the framework of BD theory in a non-flat universe [52]. This is interesting because local astronomical experiments set a very high lower bound on ω [66]; in particular, the Cassini experiment implies that ω > 104 [46,48]. We obtain the equation of motions of GDE in BD theory For this purpose, we first take the time derivative of relation (21).

Data fitting method

Results

Conclusion