The smooth spin-down of young pulsars is perturbed by two non-deterministic phenomenon , glitches and timing noise .
Although the timing noise provides insights into nuclear and plasma physics at extreme densities , it acts as a barrier to high-precision pulsar timing experiments .
An improved methodology based on Bayesian inference is developed to simultaneously model the stochastic and deterministic parameters for a sample of 85 high- \dot { E } radio pulsars observed for \sim 10 years with the 64-m Parkes radio telescope .
Timing noise is known to be a red process and we develop a parametrization based on the red-noise amplitude ( A _ { red } ) and spectral index ( \beta ) .
We measure the median A _ { red } to be -10.4 ^ { +1.8 } _ { -1.7 } yr ^ { 3 / 2 } and \beta to be -5.2 ^ { +3.0 } _ { -3.8 } and show that the strength of timing noise scales proportionally to \nu ^ { 1 } | \dot { \nu } | ^ { -0.6 \pm 0.1 } , where \nu is the spin frequency of the pulsar and \dot { \nu } its spin-down rate .
Finally , we measure significant braking indices for 19 pulsars , proper motions for two pulsars and discuss the presence of periodic modulation in the arrival times of five pulsars .