Radio Polarization of the Young High–Magnetic‐Field Pulsar PSR J1119−6127

Abstract

We have investigated the radio polarization properties of PSR J1119� 6127, a recently discovered young radio pulsar with a large magnetic field. Using pulsar-gated radio imaging data taken at a center frequency of 2496 MHz with the Australia Telescope Compact Array, we have determined a rotation measure for the pulsar of +842 � 23 rad m � 2 . These data, combined with archival polarimetry data taken at a center frequency of 1366 MHz with the Parkes telescope, were used to determine the polarization characteristics of PSR J1119� 6127 at both frequencies. The pulsar has a fractional linear polarization of � 75% and � 55% at 1366 and 2496 MHz, respectively, and the profile consists of a single, wide component. This pulse morphology and high degree of linear polarization are in agreement with previously noticed trends for young pulsars (e.g., PSR J1513� 5908). A rotating vector (RV) model fit of the position angle of linear polarization over pulse phase using the Parkes data suggests that the radio emission comes from the leading edge of a conal beam. We discuss PSR J1119� 6127 in the context of a recent theoretical model of pulsar spin-down, which can in principle be tested with polarization and timing data from this pulsar. Geometric constraints from the RV fit are currently insufficient to test this model with statistical significance, but additional data may allow such a test in the future. Subject headings: polarization — pulsars: individual (PSR J1119� 6127) — radio continuum: stars — stars: neutron Pulsar polarimetry is one of the keys to understanding the process and geometry of radio emission from pulsars. In the rotating vector (RV) model (Radhakrishnan & Cooke 1969) the polarization of pulsar radio emission is linked to the emission geometry in such a way that as the pulsar rotates, the axis of linear polarization is aligned with the projected direction on the sky of the pulsar’s magnetic dipole axis. The pulsar’s emission geometry itself may be described by two angles, each measured from the pulsar’s angular