A closer look at the cosmological implications of the ΛHDE model

Abstract In a previous paper, we proposed a heterotic dark energy model, called Λ holographic dark energy (ΛHDE), in which dark energy is composed of two components: cosmological constant (CC) and HDE. The aim of this work is to give a more comprehensive and systematic investigation on the cosmological implications of the ΛHDE model. First, we make use of the current observations to constrain the ΛHDE model, and compare its cosmology-fit results with the results of the Λ cold dark matter (ΛCDM) and the HDE model. Then, by combining a qualitative theoretical analysis with a quantitative numerical study, we discuss the impact of considering curvature on the cosmic evolutions of fractional HDE density Ωhde and fractional CC density ΩΛ, as well as on the ultimate cosmic fate. Finally, we explore the effects of adopting different types of observational data. We find that: (1) the current observational data cannot distinguish the ΛHDE model from the ΛCDM and the HDE model; this indicates that dark energy (DE) may contain multiple components. (2) The asymptotic solution of Ωhde and the corresponding cosmic fate in a flat universe can be extended to the case of a non-flat universe; moreover, compared with the case of a flat universe, considering curvature will make HDE closer to a phantom DE. (3) Compared with Joint Light-curve Analysis (JLA) data set, Supernova Legacy Survey three-years (SNLS3) data more favour a phantom type HDE; in contrast, using other types of observational data have no significant impact on the cosmic evolutions of the ΛHDE model.