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Observational constraints on the nature of dark energy: First cosmological results from the ESSENCE supernova survey
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2007 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 666, no 2, 694-715 p.Article, review/survey (Refereed) Published
Abstract [en]

We present constraints on the dark energy equation-of-state parameter, w = P/(rho c(2)), using 60 SNe Ia fromthe ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat universe. By including constraints on (Omega(M), w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1:05(-0.12)(+0: 13) (stat 1 sigma) +/- 0: 13 (sys) and Omega(M) = 0:274(-0.020)(+0:033) (stat 1 sigma) with a bestfit chi(2)/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 sigma) +/- 0: 13 ( sys), Omega(M) 0:267(-0:028)(+0:028) (stat 1 sigma) with a best-fit chi(2)/dof of 0.91. The current global SN Ia data alone rule out empty (Omega(M) = 0), matter-only Omega(M) = 0: 3, and Omega(M) = 1 universes at > 4.5 sigma. The current SN Ia data are fully consistent with a cosmological constant.

Place, publisher, year, edition, pages
2007. Vol. 666, no 2, 694-715 p.
Keyword [en]
cosmological parameters, cosmology : observations, supernovae : general
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:su:diva-55908DOI: 10.1086/518642ISI: 000249305700007OAI: diva2:409820
authorCount :37Available from: 2011-04-11 Created: 2011-03-30 Last updated: 2011-04-11Bibliographically approved

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Sollerman, Jesper
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