Constraining dynamical dark energy with a divergence-free parametrization in the presence of spatial curvature and massive neutrinos

Abstract

In this paper, we report the results of constraining the dynamical dark energy with a divergence-free parameterization, $w(z)=w_0+w_a(\frac{\ln (2+z)}{1+z}-\ln 2)$, in the presence of spatial curvature and massive neutrinos, with the 7-yr WMAP temperature and polarization data, the power spectrum of LRGs derived from SDSS DR7, the Type Ia supernova data from Union2 sample, and the new measurements of $H_0$ from HST, by using a MCMC global fit method. Our focus is on the determinations of the spatial curvature, ${\Omega }_k$, and the total mass of neutrinos, $\sum m_{\nu }$, in such a dynamical dark energy scenario, and the influence of these factors to the constraints on the dark energy parameters, $w_0$ and $w_a$. We show that ${\Omega }_k$ and $\sum m_{\nu }$ can be well constrained in this model; the 95% CL limits are: $-0.0153<{\Omega }_k<0.0167$ and $\sum m_{\nu }<0.56$ eV. Comparing to the case in a flat universe, we find that the error in $w_0$ is amplified by 25.51%, and the error in $w_a$ is amplified by 0.14%; comparing to the case with a zero neutrino mass, we find that the error in $w_0$ is amplified by 12.24%, and the error in $w_a$ is amplified by 1.63%.

Comments: 5 pages, 2 figures; discussions added; accepted for publication in Physics Letters B