On frequency dependence of pulsar linear polarization

Abstract

Frequency dependence of pulsar linear polarization is investigated by simulations of emission and propagation processes. Linearly polarized waves are generated through curvature radiation by relativistic particles streaming along curved magnetic field lines, which have ordinary mode (O-mode) and extra-ordinary mode (X-mode) components. As emitted waves propagate outwards, two mode components are separated due to re- fraction of the O mode, and their polarization states are also modified. According to the radius to frequency mapping, low frequency emission is generated from higher magnetosphere, where significant rotation effect leads the X and O modes to be sepa- rated. Hence, the low frequency radiation has a large fraction of linear polarization. As the frequency increases, emission is generated from lower heights, where the rotation effect becomes weaker and the distribution regions of two modes are more overlapped. Hence, more significant depolarization appears for emission at higher frequencies. In addition, refraction effect of the O mode becomes serious in very deep magnetosphere, which bends the O mode emission towards outer parts of a pulsar beam and also causes the separation of mode distribution regions and hence the fractional linear polariza- tion increasing with frequency. If emission of different frequencies is generated from a region of the same height, serious O mode refraction can result in the decrease of both profile width and fractional linear polarization. The observed frequency dependence of linear polarization for some pulsars can be naturally explained within the scope of our scenario.

arXiv comment11 pages,10 figures. Accepted for publication in MNRAS

References in corpus (18)

• Profile and polarization characteristics of energetic pulsars
• Polarization Changes of Pulsars due to Wave Propagation Through Magnetospheres
• On the mean profiles of radio pulsars I: Theory of the propagation effects
• Pair cascades in the magnetospheres of strongly-magnetized neutron stars
• Pulsar Radio Emission Altitude from Curvature Radiation
• Multi-frequency integrated profiles of pulsars
• An inverse Compton scattering (ICS) model of pulsar emission: III. polarization
• High frequency observations of southern pulsars
• Polarization Properties of Nine Southern Radio Pulsars
• Polarization observations of 100 pulsars at 774 MHz by the Green Bank Telescope
• The nature of pulsar radio emission
• Polarisation profiles of southern pulsars at 3.1 GHz
• Curvature Radiation in Rotating Pulsar Magnetosphere
• Relativistic model on pulsar radio emission and polarization
• The High Time Resolution Universe Survey - IX: Polarimetry of long-period pulsars
• Polarized Curvature Radiation in Pulsar Magnetosphere
• Modeling the frequency-dependence of radio beams for cone-dominant pulsars
• Role of rotation and polar cap current on pulsar radio emission and polarization

Cited by in corpus (7)

• A Living Theory Catalogue for Fast Radio Bursts
• The Thousand-Pulsar-Array program on MeerKAT -- IX. The time-averaged properties of the observed pulsar population
• The Statistical Polarization Properties of Coherent Curvature Radiation by Bunches: Application to Fast Radio Burst Repeaters
• Highly polarized components of integrated pulse profiles
• A model for distortions of polarisation-angle curves in radio pulsars
• Evidence for scattering of curvature radiation in radio pulsar profiles
• 50-250 MHz Pulsar Census with an SKA-Low prototype station: Spectra and Polarization