Speaker
Description
Single pulses of pulsars show a wealth of phenomena, e.g. drifting subpulses where subpulses systematically march in pulse phase. Such single pulse phenomena are revealed with unprecedented details by using highly sensitive and long enough observations. In addition, the evolution of drifting subpulses across the pulsar population can be studied with large survey projects. These provide crucial clues to the fundamental pulsar emission mechanisms, e.g. if and how the emissions are produced by subbeams rotating around the magnetic axis (the rotation carousel model). In this talk, I will give an overview of the Thousand-Pulsar-Array programme (TPA) on MeerKAT (part of the MeerTime Large Survey Project), the biggest southern hemisphere slow pulsar survey -- to study the pulse shape variability from pulse-to-pulse in 1198 pulsars. In particular, the periodicity of drifting subpulses evolves non-monotonically over the lifetime of pulsars. This non-monotonic evolution strongly suggests that young pulsars possess aliased fast intrinsic modulation. Modelling drifting subpulses as subbeams rotating about the magnetic axis of the pulsar, their circulation must slow down as the pulsar evolves. This is the opposite to the text-book explanation of drifting subpulses due to an ExB drift, and can be resolved if the observed periodicity is due to a beat between an ExB system and the pulsar period. I will also talk about an ongoing project of interpulse pulsars, where the emissions are seen from both magnetic poles. Most interestingly, the emissions are observed to be correlated, while the exact mechanisms for such correlation are still not understood. I will review the analysis of 30+ pulsars in the TPA sample with additional FAST observations for their interesting emission features, giving a flavour of the richness phenomena seen from these pulsars.
