Probing interaction and spatial curvature in the holographic dark energy model

TL;DR

This study constrains the interaction and spatial curvature in the holographic dark energy model using recent observational data, revealing small interaction and curvature effects and a significant degeneracy between these parameters.

Contribution

It provides the first comprehensive observational constraints on both interaction and spatial curvature in the holographic dark energy model.

Findings

Interaction and curvature are both small in the model.

Significant degeneracy exists between interaction and curvature.

Observational data constrains the model parameters effectively.

Abstract

In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term $Q$ is proportional to the energy densities of dark energy ($\rho_{\Lambda}$), matter ($\rho_{m}$), and matter plus dark energy ($\rho_m+\rho_{\Lambda}$). For probing the interaction and spatial curvature in the holographic dark energy model, we use the latest observational data including the type Ia supernovae (SNIa) Constitution data, the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). Our results show that the interaction and spatial curvature in the holographic dark energy model are both rather small. Besides, it is interesting to find that there exists significant degeneracy between the phenomenological interaction and the spatial curvature in the holographic dark energy model.