出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In this article we revise the problemof anomalous values of pulsar’ braking indices and frequency second derivatives arising in observations. The intrinsic evolutionary braking is buried deep under the superimposed non-evolutionary processes, that prevent to estimate directly its parameters for the majority of pulsars. We re-analyze the distribution of “ordinary” radio pulsars on a n¨ −n˙ and nobs−tch diagrams assuming their spin-down to be a superposition of a “true” monotonous and a symmetric oscillational terms. We demonstrated that their influences may be clearly separated using simple ad-hoc arguments. Using maximum likelihood estimator we derived the parameters of both components and found the pulsar’ peculiar evolution to be consistent with classical magnetodipolar law with braking index n ≈ 3, while the oscillations are large enough to significantly vary the observed spin-down rate and completely dominate the second frequency derivatives. So, observed pulsar’ characteristic ages (and similar estimators that dependend on the observed n˙ ) are biased up to 0.5...5 times. This naturally resolves the discrepancy of characteristic and independently estimated physical ages of several objects, as well as explain very large, up to 108 years, characteristic ages of some pulsars. We suggest these oscillations to be connected with the long-term precession of NS around its magnetic axis, probably under the influence of anomalous braking torque.
