We explore the distance-redshift relation using a cosmographic methodology , and show how the cosmographic parameters can be used to determine the redshift of transition from deceleration to acceleration .
Such a transition at a low redshift occupies only a small region of the available parameter space , and the prior assumption of an early period of deceleration can significantly change the posterior constraints .
We use available type Ia Supernovae ( SN-Ia ) and Baryon Acoustic Oscillation ( BAO ) data sets to determine the cosmographic deceleration q _ { 0 } , jerk j _ { 0 } , snap s _ { 0 } and lerk l _ { 0 } parameters .
The parameters are consistent with the \Lambda CDM model for a flat universe within 2-sigma .
We derive constraints on the redshift of transition from deceleration to acceleration for the different expansions , and find z _ { acc } > 0.14 at 95 % confidence in the most conservative case .