# Improved cosmological constraints on the curvature and equation of state of dark energy - Astrophysics > Cosmology and Nongalactic Astrophysics

Improved cosmological constraints on the curvature and equation of state of dark energy - Astrophysics > Cosmology and Nongalactic Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We apply the Constitution compilation of 397 supernova Ia, the baryonacoustic oscillation measurements including the $A$ parameter, the distanceratio and the radial data, the five-year Wilkinson microwave anisotropy probeand the Hubble parameter data to study the geometry of the universe and theproperty of dark energy by using the popular Chevallier-Polarski-Linder andJassal-Bagla-Padmanabhan parameterizations. We compare the simple $\chi^2$method of joined contour estimation and the Monte Carlo Markov chain method,and find that it is necessary to make the marginalized analysis on the errorestimation. The probabilities of $\Omega k$ and $w a$ in theChevallier-Polarski-Linder model are skew distributions, and the marginalized$1\sigma$ errors are $\Omega m=0.279^{+0.015} {-0.008}$,$\Omega k=0.005^{+0.006} {-0.011}$, $w 0=-1.05^{+0.23} {-0.06}$, and$w a=0.5^{+0.3} {-1.5}$. For the Jassal-Bagla-Padmanabhan model, themarginalized $1\sigma$ errors are $\Omega m=0.281^{+0.015} {-0.01}$,$\Omega k=0.000^{+0.007} {-0.006}$, $w 0=-0.96^{+0.25} {-0.18}$, and$w a=-0.6^{+1.9} {-1.6}$. The equation of state parameter $wz$ of dark energyis negative in the redshift range $0\le z\le 2$ at more than $3\sigma$ level.The flat $\Lambda$CDM model is consistent with the current observational dataat the $1\sigma$ level.

Autor: Nana Pan, Yungui Gong, Yun Chen, Zong-Hong Zhu

Fuente: https://arxiv.org/