On the Multi-frequency Emission Regions of the Mode Switching Pulsar PSR J0614+2229

The young pulsar PSR J0614+2229 is one of a few known pulsars with phase offset during mode switching. With the polarimetry data at 10cm, 20cm and 50cm archived at Parkes Observatory, we employ the Rotating Vector Model to fit the linear polarization position angle data for the burst and normal modes at each frequency and obtained the phases offsets between the steepest slope-rate points of best-fit curve. Using the relativistic method that is widely used to determine the emission altitude, we firstly calculate the difference between the emission altitudes of the two modes. It is found that the emission altitude of the normal mode is higher than that of the burst mode, and the difference increases with frequency. On the basis of the phase offset between the centers of the averaged pulse windows of the two modes, it is inferred that the emission regions of the two modes should not be symmetric, in the same time, about the meridian plane that contains the rotation and magnetic axes of the pulsar.