Observational Constraints on the Nature of the Dark Energy: First Cosmological Results From the ESSENCE Supernova Survey

Journal Article · Fri Jan 05 04:00:00 EST 2007 · Submitted to Astrophys.J.

DOI:https://doi.org/10.1086/518642· OSTI ID:896931

Wood-Vasey, W Michael; Miknaitis, G; Stubbs, C W; Jha, S; Riess, A G; Garnavich, P M; Kirshner, R P; Aguilera, C; Becker, A C; Blackman, J W; Blondin, S; Challis, P; Clocchiatti, A; Conley, A; Covarrubias, R; Davis, T M; Filippenko, A V; Foley, R J; Garg, A; Hicken, M ; Krisciunas, K

We present constraints on the dark energy equation-of-state parameter, w = P/({rho}c{sup 2}), using 60 Type Ia supernovae (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 ({Omega}{sub M}, w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1.05{sub -0.12}{sup +0.13} (stat 1{sigma}) {+-} 0.13 (sys) and {Omega}{sub M} = 0.274{sub -0.020}{sup +0.033} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.96. These results are consistent with those reported by the Super-Nova Legacy Survey in 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 currently 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 SuperNova Legacy Survey SNe Ia, we obtain a joint constraint of w = -1.07{sub -0.09}{sup +0.09} (stat 1{sigma}) {+-} 0.13 (sys), {Omega}{sub M} = 0.267{sub -0.018}{sup +0.028} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.91. The current SNe Ia data are fully consistent with a cosmological constant.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 896931
• Report Number(s): SLAC-PUB-12281; astro-ph/0701041
• Journal Information: Submitted to Astrophys.J., Journal Name: Submitted to Astrophys.J.
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACOUSTICS
Astrophysics
ASTRO
BARYONS
COSMOLOGICAL CONSTANT
DUSTS
GALAXIES
OSCILLATIONS
SUPERNOVAE
UNIVERSE