Cosmological model of the interaction between dark matter and dark energy

We tested a cosmological model for the interaction between dark matter and dark energy with a dynamic equation of state wDE(z) = w0 + w1z/ (1 + z), using type Ia supernovae (SNe Ia), Hubble parameter data, baryonic acoustic oscillation (BAO) measurements, and cosmic microwave background (CMB) observations. This interacting cosmological model has not been studied before. The best-fit parameters with 1σ uncertainties are δ = − 0.022 ± 0.006, Ω0DM = 0.213 ± 0.008, w0 = − 1.210 ± 0.033 and w1 = 0.872 ± 0.072 with χ2min/d.o.f. = 0.990. At the 1σ confidence level, we find δ < 0, which means that the energy transfer prefer ably occurring from dark matter to dark energy. We also find that the SNe Ia data disagree with the combined CMB, BAO, and Hubble parameter data. The evolution of ρDM/ρDE indicates that this interacting model is a good approach to solve the coincidence problem, because ρDE decreases with scale factor a. The transition redshift is ztr = 0.63 ± 0.07 in this model