The value of the equation of state of dark energy

Abstract

From recent CMB and Large Scale Structure observations the value of the equation of state of dark energy, assuming it to be constant in time, is constrained to be -1.3<w<-0.7 at the 95% confidence level: consistent with dark energy being a classical vacuum term. Here we describe two novel and independent methods, sensitive to different systematics, that give the same value for w and similar confidence regions. This suggests that systematics are not an issue in current determinations of w. The first method yields a measurement of $w$ that relies on the minimum number of model-dependent parameters; the second method is a non-parametric measurement of the time dependence of w(z). We also present a method to statistically determine the edge of a distribution.

Invited talk to appear in New Astronomy Reviews, Proceedings of the 2nd CMBNET Meeting, 20-21 February 2003, Oxford, UK

References in corpus (4)

• Phantom Energy and Cosmic Doomsday
• Constraints on the equation of state of dark energy and the Hubble constant from stellar ages and the CMB
• The internal structure of the lens PG1115+080: breaking degeneracies in the value of the Hubble Constant
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