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Observational Constraints on the Nature of Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
Author(s) -
W. M. WoodVasey,
G. Miknaitis,
C. W. Stubbs,
Saurabh W. Jha,
Adam G. Riess,
P. Garnavich,
R. Kirshner,
C. Aguilera,
A. Becker,
Joshua W. Blackman,
S. Blondin,
Peter Challis,
A. Clocchiatti,
A. Conley,
R. Covarrubias,
T. M. Davis,
A. V. Filippenko,
R. J. Foley,
Arti Garg,
M. Hicken,
K. Krisciunas,
B. Leibundgut,
Wenyu Li,
T. Matheson,
A. Miceli,
Gautham Narayan,
G. Pignata,
J. L. Prieto,
A. Rest,
M. Salvo,
B. Schmidt,
R. C. Smith,
J. Sollerman,
J. Spyromilio,
J. Tonry,
N. B. Suntzeff,
A. Zenteno
Publication year - 2007
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/518642
Subject(s) - physics , dark energy , supernova , astrophysics , redshift , baryon acoustic oscillations , galaxy , equation of state , cosmological constant , cosmology , baryon , astronomy , theoretical physics , quantum mechanics
We present constraints on the dark energy equation-of-state parameter,w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernovasurvey. We derive a set of constraints on the nature of the dark energyassuming a flat Universe. By including constraints on (Omega_M, w) from baryonacoustic oscillations, we obtain a value for a static equation-of-stateparameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) andOmega_M=0.274^{+0.033}_{-0.020} (stat; 1 sigma) with a best-fit chi^2/DoF of0.96. These results are consistent with those reported by the SuperNova LegacySurvey in a similar program measuring supernova distances and redshifts. Weevaluate sources of systematic error that afflict supernova observations andpresent Monte Carlo simulations that explore these effects. Currently, thelargest systematic currently with the potential to affect our measurements isthe treatment of extinction due to dust in the supernova host galaxies.Combining our set of ESSENCE SNe Ia with the SuperNova Legacy Survey SNe Ia, weobtain a joint constraint of w=-1.07^{+0.09}_{-0.09} (stat; 1 sigma) +- 0.12(sys), Omega_M=0.267^{+0.028}_{-0.018} (stat; 1 sigma) with a best-fitchi^2/DoF of 0.91. The current SN Ia data are fully consistent with acosmological constant.

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