A strong $\ddotν - \dotν$ correlation in radio pulsars with implications for torque variations

Abstract

We present an analysis of the spin-down parameters for 131 radio pulsars for which $\ddotν$ has been well determined. These pulsars have characteristic ages ranging from $10^{3} - 10^{8}$ yr and spin periods in the range 0.4--30 s; nearly equal numbers of pulsars have $\ddotν>0$ as $\ddotν<0$. We find a strong correlation of $\ddotν$ with $\dotν$, {\em independent of the sign of} $\ddotν$. We suggest that this trend can be accounted for by small, stochastic deviations in the spin-down torque that are directly proportional (in magnitude) to the spin-down torque.