Current Observational Constraints to Holographic Dark Energy Model with New Infrared cut-off via Markov Chain Monte Carlo Method

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In this paper, the holographic dark energy model with new infrared (IR) cut-off for both the flat case and the non-flat case are confronted with the combined constraints of current cosmological observations: type Ia Supernovae, Baryon Acoustic Oscillations, current Cosmic Microwave Background, and the observational hubble data. By utilizing the Markov Chain Monte Carlo (MCMC) method, we obtain the best fit values of the parameters with 1σ, 2σ errors in the flat model: Ωbh²=0.0233⁺⁰.⁰⁰⁰⁹ ⁺⁰.⁰⁰¹³₋₀.₀₀₀₉ ₋₀.₀₀₁₄, α=0.8502⁺⁰.⁰⁹⁸⁴ ⁺⁰.¹²⁹⁹₋₀.₀₈₇₅ ₋₀.₁₀₆₄, β=0.4817⁺⁰.⁰⁸⁴² ⁺⁰.¹¹⁷⁶₋₀.₀₇₇₃ ₋₀.₀₉₅₅, Ωde0=0.7287⁺⁰.⁰²⁹⁶ ⁺⁰.⁰⁴³²₋₀.₀₂₉₄ ₋₀.₀₄₂₉, Ωₘ₀=0.2713⁺⁰.⁰²⁹⁴ ⁺⁰.⁰⁴²⁹₋₀.₀₂₉₆ ₋₀.₀₄₃₂, H₀=66.35⁺².³⁸ ⁺³.³⁵₋₂.₁₄ ₋₃.₀₇. In the non-flat model, the constraint results are found in 1σ, 2σ regions: Ωbh²=0.0228⁺⁰.⁰⁰¹⁰ ⁺⁰.⁰⁰¹⁴₋₀.₀₀₁₀ ₋₀.₀₀₁₄, Ωₖ=0.0305⁺⁰.⁰⁰⁹² ⁺⁰.⁰¹⁴⁰₋₀.₀₁₃₄ ₋₀.₀₁₇₆, α=0.8824⁺⁰.²¹⁸⁰ ⁺⁰.²²¹³₋₀.₁₁₆₃ ₋₀.₁₃₇₈, β=0.5016⁺⁰.⁰⁹⁷³ ⁺⁰.¹²⁴⁷₋₀.₀₈₇₁ ₋₀.₁₁₀₂, Ωde0=0.6934⁺⁰.⁰³⁶⁴ ⁺⁰.⁰⁴⁹⁵₋₀.₀₃₀₄ ₋₀.₀₄₁₃, Ωₘ₀=0.2762⁺⁰.⁰²⁷⁸ ⁺⁰.⁰⁴⁰²₋₀.₀₃₂₀ ₋₀.₀₄₁₂, H₀=70.20⁺³.⁰³ ⁺³.⁵⁸₋₃.₁₇ ₋₄.₀₀. In the best fit holographic dark energy models, the equation of state of dark energy and the deceleration parameter at present are characterized by wde0=-1.1414±0.0608, q₀=-0.7476±0.0466 (flat case) and wde0=-1.0653±0.0661, q₀=-0.6231±0.0569 (non-flat case). Compared to the ΛCDM model, it is found the current combined datasets do not favor the holographic dark energy model over the ΛCDM model.