Phase-resolved Faraday rotation in pulsars
ArXiv 0903.5511 (2009)
Abstract:
We have detected significant Rotation Measure variations for 9 bright pulsars, as a function of pulse longitude. An additional sample of 10 pulsars showed a rather constant RM with phase, yet a small degree of RM fluctuation is visible in at least 3 of those cases. In all cases, we have found that the rotation of the polarization position angle across our 1.4 GHz observing band is consistent with the wavelength-squared law of interstellar Faraday Rotation. We provide for the first time convincing evidence that RM variations across the pulse are largely due to interstellar scattering, although we cannot exclude that magnetospheric Faraday Rotation may still have a minor contribution; alternative explanations of this phenomenon, like erroneous de-dispersion and the presence of non-orthogonal polarization modes, are excluded. If the observed, phase-resolved RM variations are common amongst pulsars, then many of the previously measured pulsar RMs may be in error by as much as a few tens of rad m-2.The complex polarization angles of radio pulsars: orthogonal jumps and interstellar scattering
ArXiv 0901.1826 (2009)
Abstract:
Despite some success in explaining the observed polarisation angle swing of radio pulsars within the geometric rotating vector model, many deviations from the expected S-like swing are observed. In this paper we provide a simple and credible explanation of these variations based on a combination of the rotating vector model, intrinsic orthogonally polarized propagation modes within the pulsar magnetosphere and the effects of interstellar scattering. We use simulations to explore the range of phenomena that may arise from this combination, and briefly discuss the possibilities of determining the parameters of scattering in an effort to understand the intrinsic pulsar polarization.Phase-resolved Faraday rotation in pulsars
Monthly Notices of the Royal Astronomical Society 396:3 (2009) 1559-1572
Abstract:
We have detected significant rotation measure (RM) variations for nine bright pulsars, as a function of pulse longitude. An additional sample of 10 pulsars showed a rather constant RM with phase, yet a small degree of RM fluctuation is visible in at least three of those cases. In all cases, we have found that the rotation of the polarization position angle across our 1.4 GHz observing band is consistent with the λ2 law of interstellar Faraday rotation. We provide for the first time convincing evidence that RM variations across the pulse are largely due to interstellar scattering, although we cannot exclude that magnetospheric Faraday rotation may still have a minor contribution; alternative explanations of this phenomenon, like erroneous de-dispersion and the presence of non-orthogonal polarization modes, are excluded. If the observed, phase-resolved RM variations are common amongst pulsars, then many of the previously measured pulsar RMs may be in error by as much as a few tens of rad m-2. © 2009 RAS.The complex polarization angles of radio pulsars: Orthogonal jumps and interstellar scattering
Monthly Notices of the Royal Astronomical Society: Letters 392:1 (2009)
Abstract:
Despite some success in explaining the observed polarization angle swing of radio pulsars within the geometric rotating vector model, many deviations from the expected S-like swing are observed. In this Letter, we provide a simple and credible explanation of these variations based on a combination of the rotating vector model, intrinsic orthogonally polarized propagation modes within the pulsar magnetosphere and the effects of interstellar scattering. We use simulations to explore the range of phenomena that may arise from this combination, and briefly discuss the possibilities of determining the parameters of scattering in an effort to understand the intrinsic pulsar polarization. © 2008 The Author. Journal compilation © 2008 RAS.A New Model for the Beams of Radio Pulsars
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