Frequency dependence of orthogonal polarisation modes in pulsars

We have carried out a study of the orthogonal polarisation mode behaviour as afunction of frequency of 18pulsars, using average pulsar data from the European Pulsar Network(EPN). Assuming that the radiation consists of two100% polarised completely orthogonal superposed modes we separated these modes, resulting in average pulse profiles of each mode at multiple frequencies for each pulsar. Furthermore, we studied the frequency dependence of the relative intensity of these modes. We found in many pulsars that the average pulse profiles of the twomodes differ in their dependence on frequency. In particular, we found that pulse components that are dominated by onemode tend to increase in intensity with increasing frequency with respect to the rest of the profile.