Observational constraints on the nature of dark energy: First cosmological results from the essence supernova survey

Wood-Vasey, WM; Miknaitis, G.; Stubbs, CW; Jha, S.; Riess, AG; Garnavich, PM; Kirshner, RP; Aguilera C.; Becker, AC; Blackman, JW; Blondin S.; Challis, P; Clocchiatti, A.; Conley, A.; Covarrubias, R.; et. al.

Abstract

We present constraints on the dark energy equation-of-state parameter, w = P/(pc2), using 60 SNe Ia from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat universe. By including constraints on (ΩM, w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1.05+0.13 -0.12 (stat 1 σ)±0.13 (sys) and ΩM= 0.274-0.020 +0.033 (stat 1σ ) with a bestfit x2/dof of 0.96. These results are consistent with those reported by the Supernova Legacy Survey from the first year of a similar program measuring supernova distances and redshifts. We evaluate sources of systematic error that afflict supernova observations and present Monte Carlo simulations that explore these effects. Currently, the largest systematic with the potential to affect our measurements is the treatment of extinction due to dust in the supernova host galaxies. Combining our set of ESSENCE SNe Ia with the first-results Supernova Legacy Survey SNe Ia, we obtain a joint constraint of w = -1.07-0.09 +0.09(stat 1 σ) ±0.13 (sys), ΩM = 0.267-0.018 +0.028 (stat 1 σ) with a best-fit x2/dof of 0.91. The current global SN Ia data alone rule out empty (ΩM = 0), matter-only ΩM = 0.3, and ΩM = 1 universes at >4.5 σ. The current SN Ia data are fully consistent with a cosmological constant. © 2007. The American Astronomical Society. All rights reserved.

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Título según WOS: Observational constraints on the nature of dark energy: First cosmological results from the ESSENCE supernova survey
Título según SCOPUS: Observational constraints on the nature of dark energy: First cosmological results from the essence supernova survey
Título de la Revista: ASTROPHYSICAL JOURNAL
Volumen: 666
Número: 2
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2007
Página de inicio: 694
Página final: 715
Idioma: English
URL: http://www.scopus.com/inward/record.url?eid=2-s2.0-35348887272&partnerID=q2rCbXpz
Notas: ISI, SCOPUS