Wednesday, July 3, 2013

1307.0297 (T. V. Shabanova et al.)

Timing Observations of 27 Pulsars at the Pushchino Observatory from 1978 to 2012    [PDF]

T. V. Shabanova, V. D. Pugachev, K. A. Lapaev
We present results from timing observations of 27 pulsars made at the Pushchino Observatory during 33.5 yr between 1978 July and 2012 February. The addition to our data spans for 10 pulsars with the archival Jet Propulsion Laboratory data extends individual data spans up to 43.5 yr. We detected a new phenomenon in the timing behavior of two pulsars, B0823+26 and B1929+10, that demonstrates a rapid change of pulsar rotation parameters such that a sign of the second derivative $\ddot\nu$ is reversed. An analysis of the $\ddot\nu$ changes showed that this process can be considered as a modulation process in $\ddot\nu$. We showed that a process of a rapid change of pulsar rotation parameters represents a new type of rotational irregularities that together with other three types of rotational irregularities---discrete glitches, slow glitches and quasi-periodic oscillations, forms a large-scale structure of timing noise and all they are the cause of deviation of the timing behavior of most ordinary pulsars from a simple spin-down model. We found that all four types of observed rotational irregularities have evolutional nature. Irregularities in pulsar rotation rate pass through three evolutional stages which exhibit that a certain type of rotational irregularities can occur only at a certain stage of pulsar rotation evolution. The age boundaries between different evolutional stages are indistinct, diffusive. This happens because different pulsars having similar properties evolve along different paths. The evolutionary scenario of the occurrence of rotational irregularities well explains many observed properties of pulsar rotation.
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