http://arxiv.org/abs/1705.08797
In this paper we present conjoined constraints on several cosmological models from the expansion history $H(z)$ and cosmic growth $f\sigma_8$. The models we studied include the CPL $w_0w_a$ parametrization, the Holographic Dark Energy (HDE) model, the Time varying vacuum ($\Lambda_t$CDM) model, the Dvali, Gabadadze and Porrati (DGP) and Finsler-Randers (FRDE) model, a power law $f(T)$ model and finally the Hu-Sawicki $f(R)$ model. In all cases we used the best-fit parameters as determined in Basilakos and Nesseris (2016) and we followed the conjoined visualization of $H(z)$ and $f\sigma_8$ as in Linder (2017). Also, we introduce the Figure of Merit (FoM) in the $H(z)-f\sigma_8$ parameter space as a way to constrain models that jointly fit both probes well. In this regard, we used both the latest $H(z)$ and $f\sigma_8$ data, but also LSST-like mocks with $1\%$ measurements. We find that that the conjoined method of constraining the expansion history and cosmic growth simultaneously is able to not only place stringent constraints on these parameters but also provide an easy visual way to discriminate cosmological models. Finally, we found that the FoM in the conjoined parameter space of $H(z)-f\sigma_8(z)$ can be used to discriminate between the $\Lambda$CDM model and certain classes of modified gravity models, namely the DGP and $f(R)$.
S. Basilakos and S. Nesseris
Thu, 25 May 17
41/44
Comments: 10 pages, 2 figures, 4 tables, comments welcome
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