Observational Constraints on Phantom Crossing DGP Gravity

TL;DR

This paper investigates an extended DGP gravity model that allows the crossing of the phantom divide, fitting observational data better than previous DGP models and explaining late-time cosmic acceleration without dark energy.

Contribution

The authors develop a modified DGP model that achieves phantom crossing and demonstrate its consistency with observational data, improving upon earlier DGP models.

Findings

The model fits observational data with $eta=0.54^{+0.24}_{-0.30}$ and $ ext{Omega}_{m,0}=0.27^{+0.02}_{-0.02}.

Crossing of the phantom divide occurs at redshift $z ext{~} 0.2$.

The model explains late-time acceleration without dark energy.

Abstract

We study the observational constraints on the Phantom Crossing DGP model. We demonstrate that the crossing of the phantom divide does not occur within the framework of the original Dvali-Gabadadze-Porrati (DGP) model or the DGP model developed by Dvali and Turner. By extending their model in the framework of an extra dimension scenario, we study a model that realizes crossing of the phantom divide. We investigate the cosmological constraints obtained from the recent observational data of Type Ia Supernovae, Cosmic Microwave Background anisotropies, and Baryon Acoustic Oscillations. The best fit values of the parameters with 1$\sigma$ (68%) errors for the Phantom Crossing DGP model are $\Omega_{m,0}=0.27^{+0.02}_{-0.02}$, $\beta=0.54^{+0.24}_{-0.30}$. We find that the Phantom Crossing DGP model is more compatible with the observations than the original DGP model or the DGP model developed by Dvali and Turner. Our model can realize late-time acceleration of the universe, similar to that of $\Lambda$CDM model, without dark energy due to the effect of DGP gravity. In our model, crossing of the phantom divide occurs at a redshift of $z \sim 0.2$.