Pulsar polarization

This is a representation of the polarization of the radio signal coming from the pulsar PSR J0337+1715. This highly magnetized neutron star emits radio waves that sweep across the sky as it rotates hundreds of times per second. As we record these waves at Earth, we see a repetitive radio signal. Part of that signal is polarized, presumably by the magnetic field in the region where the emission is produced. This object illustrates the polarization. With an elliptically polarized radio wave, the tip of the electric field vector sweeps out a spiral. The elliptical shape of this spiral contains the polarization information: the direction and length of the long axis tell us about the linear polarization, and the length of the short axis tells us about the circular polarization, while the direction of the spiral tells us about the sign of the circular polarization.