Circular Components of Polarization in Pulsar Radiation

Abstract

INDIVIDUAL radio pulses from many pulsars have been found to be highly polarized. Pulses from PSR 0329 contain a large circular component¹, so that the polarization is generally elliptical, but the handiness of the circular component appears to be variable, so that the Stokes parameter V changes in sign both during an individual pulse and from pulse to pulse. If this variation were completely random, then an integrated profile of V obtained by summing several hundred pulses would be close to zero. The Stokes parameters Q and U, on the other hand, representing linear polarization, do not sum to zero in this way and large average linear polarizations are observed in many pulsars^2–5. So far, however, only one observation² of one pulsar (PSR 1749) suggests that the average V profile is significantly different from zero. In an extended series of observations, we now find that the average V component is significantly different from zero in many pulsars, although it seldom approaches the strength of the linear component (Q² + U²)^½. The average V component is particularly strong in the pulsars PSR 0329 and PSR 1508.