Probing Dark Energy with the Cosmic Microwave Background: Projected Constraints from the Wilkinson Microwave Anisotropy Probe and Planck

We investigate the accuracy attainable by forthcoming space-based observations of the cosmic microwave background (CMB) temperature and polarization anisotropy in constraining the dark energy density parameter Ω Q and equation of state w Q = p Q /ρ Q . Despite degeneracies among parameters, it is possible for high-precision observations such as those from the Wilkinson Microwave Anisotropy Probe and Planck to provide interesting information on the nature of the dark energy. Furthermore, we show that imposing a flat universe constraint makes it possible to obtain tight limits in the space of dark energy parameters even from the CMB alone.