At present three pulsars are known which clearly show a strongly increasingdegree of circular polarization with frequency. As this is accompanied by asmooth decrease of linear polarization, we investigate, if this observation canbe explained through a propagation mode transition from linear to circularpolarization. Using a previously published model we find that the rate ofchange of the polarization types with frequency is well consistent with thetheory. The small number of only three objects does of course not allow to drawa general conclusion for the whole sample of pulsars. However we show that thevery unusual behavior of these three objects can be well explained with thismodel and we discuss, why only so few such objects are presently known.
展开▼
