Reconstructing the Cosmic Equation of State from Supernova distances

1999/10/31 by Tarun Deep Saini, Somak Raychaudhury, Varun Sahni +1
Physics and Astronomy · #astro-ph #gr-qc #hep-ph

paper · pdf · doi:10.1103/physrevlett.85.1162

published as Phys.Rev.Lett. 85 (2000) 1162-1165 · 4 pages, 5 figures, uses RevTex. Minor typo's in equations (1) and (10) corrected

arxiv created 2000/10/07 · arxiv updated 2009/11/30

Abstract

Observations of high-redshift supernovae indicate that the universe is accelerating. Here we present a \em model-independent method for estimating the form of the potential V(ϕ) of the scalar field driving this acceleration, and the associated equation of state w_ϕ. Our method is based on a versatile analytical form for the luminosity distance D_L, optimized to fit observed distances to distant supernovae and differentiated to yield V(ϕ) and w_ϕ. Our results favor w_ϕ≃ -1 at the present epoch, steadily increasing with redshift. A cosmological constant is consistent with our results.

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