Parkes observations for project P922 semester 2016APRS

Since the discovery of pulsars in 1968, significant progress has been made in our understanding of the emission mechanism of these laboratories of extreme physics. By characterising the properties of the observed emission various models aiming to explain the complex behaviour of radio pulsars can be further constrained. There are two well established models which are particularly relevant in the context of this proposal. The first model can explain most aspects of the periodic variability observed in the shape of individual pulses of many pulsars. The second model successfully explains the change of the position angle (PA) of the linear polarisation during a stellar rotation. However, there is evidence for a small number of pulsars that the PA periodically changes in tandem with the variability in the pulse shapes. This behaviour is incompatible with the well established models. Here it is proposed to observe a carefully selected sample of pulsars to establish 1) if this behaviour is a general property of the emission mechanism, 2) what geometrical configuration is responsible and 3) what this implies for the physical processes in the pulsar magnetosphere. This investigation will be aided by a new sensitive technique allowing weaker sources to be analysed.