Pulsar electrodynamics inferred from frequency-dependent circular polarization diversity

Abstract

The nature of coherent radio emission is still challenging even after more than half a century of pulsar discovery, but it is generally a consensus that single-pulse observations are essential for probing the magnetospheric dynamics, especially with the largest single-dish telescope FAST (Five-hundred-meter Aperture Spherical radio Telescope). This paper aims to explain the observed diversity of single pulse circular polarization, and to constrain the multiplicity and Lorentz factor of pulsar magnetospheric plasma, with the mode coupling model in the limiting polarization region. Assuming that circular polarization comes only from wave mode coupling, we apply a Bayesian analysis to the FAST observed single pulse circular polarization spectra, involving numerical solving of wave mode coupling equations, and analyze the posterior probability distribution functions of the parameters. Although the model fails to quantitatively fit most circular polarization spectra, circular polarization of different frequency evolution is reproduced. For three chosen pulsars, the Bayesian analysis constrains the multiplicity to be approximately $10^0\sim 10^2$, and the Lorentz factor to be approximately $10^{0.5}\sim 10^2$. Pulsar circular polarization could be induced by wave mode coupling. The plasma flow responsible for coherent radio emission carries only a very small fraction of the pulsar spin-down energy loss.

13 pages, 10 figures, published by A&A

References in corpus (30)

• emcee: The MCMC Hammer
• The ATNF Pulsar Catalogue
• TEMPO2, a new pulsar timing package. I: Overview
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• DSPSR: Digital Signal Processing Software for Pulsar Astronomy
• Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth
• Current Flow and Pair Creation at Low Altitude in Rotation Powered Pulsars' Force-Free Magnetospheres: Space-Charge Limited Flow
• Diverse polarization angle swings from a repeating fast radio burst source
• PSRCHIVE and PSRFITS: Definition of the Stokes Parameters and Instrumental Basis Conventions
• On the polar cap cascade pair multiplicity of young pulsars
• RUN DMC: An efficient, parallel code for analyzing Radial Velocity Observations using N-body Integrations and Differential Evolution Markov chain Monte Carlo
• On the maximum pair multiplicity of pulsar cascades
• Polarization Changes of Pulsars due to Wave Propagation Through Magnetospheres
• On the mean profiles of radio pulsars I: Theory of the propagation effects
• Radio pulsars: already fifty years!
• Magnetospheric curvature radiation by bunches as emission mechanism for repeating fast radio bursts
• Coherent Electromagnetic Emission from Relativistic Magnetized Shocks
• Polarisation profiles of southern pulsars at 3.1 GHz
• Chandra observations of the elusive pulsar wind nebula around PSR B0656+14
• Pulsar polarization: a partial-coherence model
• Ninety percent circular polarization detected in a repeating fast radio burst
• Evidence for Coherent Curvature Radiation in PSR J1645$-$0317 with Disordered Distribution of Polarization Position Angle
• Circular Polarization in Pulsar Integrated Profiles: Updates
• PSR B0943+10: Mode Switch, Polar Cap Geometry, and Orthogonally Polarized Radiation
• High-altitude Magnetospheric Emissions from Two Pulsars
• Poynting flux transport channels formed in polar cap regions of neutron star magnetospheres
• Rapid Rotation of Polarization Orientations in PSR B1919+21's Single Pulses: Implications On Pulsar's Magnetospheric Dynamics
• Deriving pulsar pair-production multiplicities from pulsar wind nebulae using H.E.S.S. and LHAASO observations
• Simulations of the radio polarization of a precessing pulsar PSR J1906+0746
• Origin of radio polarization in pulsar polar caps