Constraints on Cosmological Models from Hubble Parameters Measurements

Abstract

In this paper, we study the cosmological constraints from the measurements of Hubble parameters---$H(z)$ data. Here, we consider two kinds of $H(z)$ data: the direct $H_0$ probe from the Hubble Space Telescope (HST) observations of Cepheid variables with $H_0=73.8\pm 2.4$ $\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ and several measurements on the Hubble parameter at high redshifts $H(z)$. Employing Markov Chain Monte Carlo method, we also combine the WMAP nine-year data (WMAP9), the baryon acoustic oscillations (BAO) and type Ia supernovae (SNIa) "Union2.1" compilation to determine the cosmological parameters, such as the equation of state (EoS) of dark energy $w$, the curvature of the universe ${\Omega }_k$, the total neutrino mass $\sum m_{\nu }$, the effective number of neutrinos $N_{\mathrm{eff}}$, and the parameters associated with the power spectrum of primordial fluctuations. These $H(z)$ data provide extra information on the accelerate rate of our Universe at high redshifts. Therefore, adding these $H(z)$ data significantly improves the constraints on cosmological parameters, such as the number of relativistic species. Moreover, we find that direct prior on $H_0$ from HST can also give good constraints on some parameters, due to the degeneracies between these parameters and $H_0$.

12 pages, 3 figures, 8 tables. Accepted to IJMPD

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Cited by in corpus (2)

• Neutrino cosmology and Planck
• Constraints on Dark Energy from New Observations including Pan-STARRS