The state of the dark energy equation of state

By A. Melchiorri, L. Mersini, C. Odman, M. Trodden. 2002

356 citations recorded by the source corpus.

By combining data from seven cosmic microwave background experiments (including the latest WMAP results) with the Hubble parameter measurement from the Hubble space telescope and luminosity measurements of type Ia supernovae, we demonstrate the bounds on the dark energy equation of state ${w}_{Q}$ to be $\ensuremath{-}1.45l{w}_{Q}l\ensuremath{-}0.74$ at the 95% confidence level. Although our limit on ${w}_{Q}$ is improved with respect to previous analyses, cosmological data do not rule out the possibility that the equation of state parameter ${w}_{Q}$ of the dark energy Q is less than $\ensuremath{-}1.$ We present a tracking model that ensures ${w}_{Q}l~\ensuremath{-}1$ at recent times and discuss the observational consequences.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/800f61baa92b6310df57fe0138eb582b7e2cef05

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Citations in the corpus

The Essence of Quintessence and the Cost of Compression (2004, methodology): “One-parameter studies give constraints such as −1.38 < wDE < −0.82 at 2σ (Melchiorri et al. 2003) suggesting that a model with w = −5 at z = 2 would be ruled out at more than 10σ.”
Exotic solutions in General Relativity: Traversable wormholes and 'warp drive' spacetimes (2007, background): “If ω < −1 [155, 156, 157], a case certainly not excluded by observation, then the null energy condition is violated, ρ + p < 0, and consequently all of the other energy conditions.”
Approaches to understanding cosmic acceleration (2009, background): “Further, just as with minimal models, it is possible [97] to obtain phantomlike behavior, but once again, this comes at the risk of serious instabilities.”
Cosmological parameters from supernova observations: A critical comparison of three data sets (2003, unknown): “…explored, for example, in Caldwell (2002); Hannestad & Mörtsell (2002); Carroll, Hoffman, & Trodden (2003); Caldwell, Kamionkowski, & Weinberg (2003); Melchiorri et al. (2003); Singh, Sami, & Dadhich (2003); Johri (2004); Stefancic (2004); Sami & Toporensky (2004); Li & Hao (2004); Hao & Li…”
Cosmological constraints on f(R) gravity theories within the Palatini approach (2005, background): “The CMBR shift parameter (Bond et al. 1997; Melchiorri et al. 2003; Odman et al. 2003) in a spatially flat universe is given by R = √ ΩmH20 ∫ zdec 0 dz̃ H(z̃) , (18) where zdec is the redshift at decoupling.”