Constraints on the Dvali-Gabadadze-Porrati model from recent supernova observations and baryon acoustic oscillations

Although there is mounting observational evidence that the expansion of our universe is undergoing a late-time acceleration, the mechanism for this acceleration is yet unknown. In the so-called Dvali-Gabadadze-Porrati (DGP) model this phenomenon is attributed to gravitational leakage'' into extra dimensions. In this work, we mainly focus our attention on the constraints on the model from the gold sample'' of Type Ia supernovae (SNe Ia), the first-year data from the Supernova Legacy Survey (SNLS), and the baryon acoustic oscillation (BAO) peak found in the Sloan Digital Sky Survey (SDSS). At 99.73% confidence level, the combination of the three databases provides Omega(m) = 0.270(-0.017)(+0. 018) and Omega(rc) = 0.216(-0.013)(+0.012) (hence, a spatially closed universe with Omega(k) = -0.350(-0.083)(+0.080)), which seems to be in contradiction with the most recent WMAP results indicating a flat universe. Based on this result, we also estimated the transition redshift (at which the universe switches from deceleration to acceleration) to be 0.70 < z(q=0) < 1.01, at 2 sigma confidence level.