We combine complementary datasets from Cosmic Microwave Background ( CMB ) anisotropy measurements , high redshift supernovae ( SN-Ia ) observations and data from local cluster abundances and galaxy clustering ( LSS ) to constrain the dark energy equation of state parameterized by a constant pressure-to-density ratio w _ { Q } .
Under the assumption of flatness , we find w _ { Q } < -0.85 at 68 \% c.l. , providing no significant evidence for quintessential behaviour different from that of a cosmological constant .
We then generalise our result to show that the constraints placed on a constant w _ { Q } can be safely extended to dynamical theories .
We consider a variety of quintessential dynamical models based on inverse power law , exponential and oscillatory scaling potentials .
We find that SN1a observations are ‘ numbed ’ to dynamical shifts in the equation of state , making the prospect of reconstructing w ( z ) , a challenging one indeed .