Holographic dark energy interacting with dark matter

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cold dark matter coupled to a dark energy which is given by the modified holographic Ricci cutoff. The interaction used is linear in both dark energy densities, the total energy density and its derivative. Using the statistical method of ${\chi }^2$-function for the Hubble data, we obtain $H_0=73.6km\mathrm{/}sMpc$, ${\omega }_s={\gamma }_s-1=-0.842$ for the asymptotic equation of state and $z_{acc}=0.89$. The estimated values of ${\mathrm{\Omega }}_{c0}$ which fulfill the current observational bounds corresponds to a dark energy density varying in the range $0.25R<{\text{ro}}_x<0.27R$.