2016MNRAS.455.3201T

Radio pulsar J0631+1036 presents a remarkably clear example of a rare four-component profile, and with apparently large aberration/retardation indicated by its linear polarization-angle traverse, but on closer study its profiles are somewhat difficult to understand and interpret. The pulsar's four components do appear to represent inner and outer conal beam pairs with the expected spacing and spectral evolution with frequency. At metre wavelengths, the leading and trailing component pairs are often conflated into an unresolved double form by what seems to be varying amounts of scattering. We assess whether the core/double-cone geometric model, widely used to describe the profiles of slower pulsars, is appropriate for J0631+1036. We find that it is largely compatible apart from difficulties with the emission height and resolved double form of the inner conal features. An aberration/retardation analysis provides 600-km physical emission height values, which are compatible with geometric estimates for the outer conal emission. We also explore several other models and conclude that none are as successful as the core/double-cone model despite its several difficulties.