Conjoined constraints on modified gravity from the expansion history and cosmic growth

Understand

In this paper we present conjoined constraints on several cosmological models from the expansion history $H(z)$ and cosmic growth $f\sigma_8(z)$.

• The models we study 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) models, a power law $f(T)$ model and finally the Hu-Sawicki $f(R)$ model.
• In all cases we perform a simultaneous fit to the SnIa, CMB, BAO, $H(z)$ and growth data, while also following the conjoined visualization of $H(z)$ and $f\sigma_8(z)$ as in Linder (2017).
• Furthermore, we introduce the Figure of Merit (FoM) in the $H(z)-f\sigma_8(z)$ parameter space as a way to constrain models that jointly fit both probes well.