The state of the dark energy equation of state
Abstract
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 1.45<w_{Q}<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 1. We present a tracking model that ensures w_{Q}⩽1 at recent times and discuss the observational consequences.
 Publication:

Physical Review D
 Pub Date:
 August 2003
 DOI:
 10.1103/PhysRevD.68.043509
 arXiv:
 arXiv:astroph/0211522
 Bibcode:
 2003PhRvD..68d3509M
 Keywords:

 98.80.Cq;
 Particletheory and fieldtheory models of the early Universe;
 Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 7 pages, 4 figures, added a reference