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 phenomena is attributed to gravitational leakage into extra dimensions .
In this work , we mainly focus our attention to the constraints on the model from the gold sample of type Ia supernovae ( SNeIa ) , 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 ^ { +0.018 } _ { -0.017 } and \Omega _ { r _ { c } } = 0.216 ^ { +0.012 } _ { -0.013 } ( hence a spatially closed universe with \Omega _ { k } = -0.350 ^ { +0.080 } _ { -0.083 } ) , 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 .