Constraints on dark energy from supernovae, gamma-ray bursts, acoustic oscillations, nucleosynthesis, large-scale structure, and the Hubble constant

The luminosity distance versus redshift law is now measured using supernovae and gamma-ray bursts, and the angular size distance is measured at the surface of last scattering by the CMB and at z = 0.35 by baryon acoustic oscillations. In this paper, this data is fit to models for the equation of state with w = -1, w = constant, and w(z) = w(0) + w(a)(1-a). The last model is poorly constrained by the distance data, leading to unphysical solutions where the dark energy dominates at early times unless the large-scale structure and acoustic scale constraints are modified to allow for early-time dark energy effects. A flat Lambda CDM model is consistent with all the data.