http://arxiv.org/abs/1704.01774
In order to explore the generic properties of a backreaction model to explain the observations of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter is employed. However, we doubt that the evolving curvature parameter also obeys the scaling law, thus we make use of observational Hubble parameter data (OHD) to constrain parameters in dust cosmology to testify it. First, in FLRW model, after getting best-fit constraints of $\Omega^{{\mathcal{D}}0}_m = 0.25^{+0.03}{-0.03}$, $n = 0.02^{+0.69}{-0.66}$, and $H{\mathcal{D}0} = 70.54^{+4.24}{-3.97}\ {\rm km/s/Mpc}$, evolutions of parameters are studied. Second, in template metric context, by marginalizing over $H_{\mathcal{D}0}$ as a prior of uniform distribution, we obtain the best-fit values as $n=-1.22^{+0.68}{-0.41}$ and ${{\Omega}{m}^{\mathcal{D}{0}}}=0.12^{+0.04}{-0.02}$. Moreover, we utilize three different Gaussian priors of $H{\mathcal{D}0}$, which result in different best-fits of $n$, but almost the same best-fit value of ${{\Omega}{m}^{\mathcal{D}{0}}}\sim0.12$. With these constraints, evolutions of the effective deceleration parameter $q^{\mathcal{D}}$ indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra dark energy component in the scaling solution context. However, the results also imply that the prescription of the geometrical instantaneous spatially-constant curvature $\kappa{\mathcal{D}}$ of the template metric is insufficient and should be improved.
S. Cao, H. Teng, H. Yu, et. al.
Fri, 7 Apr 17
20/50
Comments: 15 pages, 9 figures, submitted to JCAP
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