Comparative analysis of the parameters of pulsars with braking indices \(n>0\) and \(n<0\)

Abstract

We analyzed the timing parameters (the rotational frequency \(\nu \), the first \(\left ( \dot{\nu } \right )\) and second \(\left ( \ddot{\nu } \right )\) time-derivatives of frequency) and the derived parameters of a sample of pulsars for which \(\ddot{\nu } \) (470 pulsars) were recorded in the Australian Telescope National Facility (ATNF) pulsar catalog. We formed various subsamples, those with braking indices \(n<0\) and \(n>0\), and glitching and non-glitching pulsars. Our statistical analyses of the timing and derived parameters indicated some level of differences and similarities among the parameters analyzed. Glitching pulsars appear to have a higher rotational frequency than non-glitching pulsars, and pulsars with \(n>0\) appear to rotate faster than those with \(n<0\). Our results also suggest that glitching pulsars have lower values of \(\left \vert n \right \vert \) (where \(\left \vert n \right \vert \) is the absolute value of the braking index), and it is lower for the subsample with \(n>0\) than for the subsample with \(n<0\). We believe that the results obtained could be useful in understanding the evolution of pulsar spin.