Constraining Dvali-Gabadadze-Porrati gravity from observational data

The accelerating expansion of our Universe at present could be driven by an unknown energy component (dark energy) or a modification of general relativity (modified gravity). In this paper we revisit the constraints on a phenomenological model which interpolates between the pure Lambda CDM model and the Dvali-Gabadadze-Porrati braneworld model with an additional parameter alpha. Combining the cosmic microwave background , baryon acoustic oscillations, and type Ia supernovae, as well as some high-redshift observations, such as the gamma-ray bursts and the measurements of linear growth factors, we obtain the tight constraint on the parameter alpha=0.254 +/- 0.153 (68% C.L.), which implies that the flat Dvali-Gabadadze-Porrati model is incompatible with the current observations, while the pure Lambda CDM model still fits the data very well. Finally, we simulate the future measurements with higher precisions and find that the constraint on alpha can be improved by a factor of 2 when compared to the present constraints.