2006/12/31 by Yungui Gong, Anzhong Wang · 6 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Radio Astronomy Observations and Technology #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.75.043520
published as Phys.Rev.D75:043520,2007 · 9 figures, added four contour plots and some discussions on the sweet spot, main conclusion unchanged; v3: references added, PRD in press
arxiv created 2007/02/13 · openalex publication_date 2007/02/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The new 182 gold supernova Ia data, the baryon acoustic oscillation measurement and the shift parameter determined from the Sloan Digital Sky Survey, and the three-year Wilkinson Microwave Anisotropy Probe data are combined to reconstruct the dark energy equation of state parameter w(z) and the deceleration parameter q(z). We find that the strongest evidence of acceleration happens around the redshift z\ensuremath∼0.2 and the stringent constraints on w(z) lie in the redshift range z\ensuremath∼0.2--0.5. At the sweet spot, \ensuremath-1.2<w(z)<\ensuremath-0.6 for the dark energy parametrization w(z)=w0+waz/(1+z)2 at the 3\ensuremathσ confidence level. The transition redshift zt when the Universe underwent the transition from deceleration to acceleration is derived to be zt=0.36_\ensuremath-0.08+0.23. The combined data is also applied to find out the geometry of the Universe, and we find that at the 3\ensuremathσ confidence level, |\ensuremathΩk|\ensuremath\lesssim0.05 for the simple one-parameter dark energy model, and \ensuremath-0.064<\ensuremathΩk<0.028 for the \ensuremathΛCDM model.