Radio Polarization Characteristics and Rotation Measures for Two Vela-like Pulsars from ATCA Observations

Using data from dual-band, pulsar-gated observations conducted with the Australia Telescope Compact Array, we present radio polarization characteristics and rotation measures for two young, Vela-like pulsars, PSRs J0940-5428 and J1301-6305. Both pulsars are highly polarized, consistent with previously noted trends for energetic pulsars. PSR J0940-5428 has measured on-pulse linear, circular, and absolute circular polarization fractions of 69 ± 2%, -6 ± 2%, and 9 ± 2% at 1384 MHz, and 71 ± 9%, -4 ± 9%, and 21 ± 9% at 2496 MHz. After correcting for bandwidth depolarization, PSR J1301-6305 has corresponding on-pulse polarization fractions of 99 ± 22%, +19 ± 8%, and 32 ± 8% at 1384 MHz, and 94 ± 10%, +32 ± 10%, and 33 ± 10% at 2496 MHz. The rotation measures of -27 ± 7 rad m^-2 for PSR J0940-5428 and -627 ± 6 rad m^-2 for PSR J1301-6305 indicate mean line-of-sight magnetic field strengths that are consistent with expected values for the Galaxy. Total intensity images of the regions have also been created as part of a larger ongoing imaging study. The images suggest that there is no obvious extended emission coincident with either pulsar from an associated supernova remnant or pulsar wind nebula, despite the young ages of these pulsars.