Observations of microglitches in Hartebeesthoek Radio Astronomy Observatory radio pulsars

A detailed observation of the microglitch phenomenon in relatively slow radio pulsars is presented. Our analyses for these small amplitude jumps in pulse rotation frequency ((nu) over dot) and/or spin-down rate ((nu) over dot)combine the traditional manual detection method (which hinges on careful visual inspections of the residuals of pulse phase residuals) and a new, and perhaps more objective, automated search technique (which exploits the power of the computer, rather than the eyes, for resolving discrete events in pulsar spin parameters). The results of the analyses of a sample of 26 radio pulsars reveal that (i) only 20 pulsars exhibit significant fluctuations in their arrival times to be considered suitable for meaningful microglitch analyses; (ii) a phenomenal 299 microglitch events were identified in nu and/or (nu) over dot: 266 of these events were found to be simultaneously significant in nu and nu, while 19 and 14 were noticeable only in nu and (nu) over dot, respectively; (iii) irrespective of sign, the microglitches have fractional sizes which cover about three orders of magnitude in nu and (nu) over dot(10(-11) < vertical bar Delta nu/nu vertical bar < 2.0 x 10(-8) and 5.0 x 10(-5) < vertical bar Delta(v) over dot/(nu) over dot vertical bar < 2.0 x 10(-2)) with median values as 0.78 x 10(-9) and 0.36 x 10(-3), respectively.