Asymmetry of bifurcated features in radio pulsar profiles

TL;DR

This paper investigates the asymmetry in bifurcated emission components of pulsar profiles, revealing a frequency of symmetry and linking the features to curvature radiation's microscopic beam properties.

Contribution

It demonstrates that the asymmetry in bifurcated emission components can be modeled by the curvature radiation microbeam, confirming the microscopic origin of certain pulsar profile features.

Findings

Identification of a frequency of symmetry in bifurcated components

Modeling of double notches with curvature radiation microbeam

Confirmation of the microscopic nature of pulsar emission beams

Abstract

High-quality integrated radio profiles of some pulsars contain bifurcated, highly symmetric emission components (BECs). They are observed when our line of sight traverses through a split-fan shaped emission beam. It is shown that for oblique cuts through such a beam, the features appear asymmetric at nearly all frequencies, except from a single `frequency of symmetry' nu_sym, at which both peaks in the BEC have the same height. Around nu_sym the ratio of flux in the two peaks of a BEC evolves in a way resembling the multifrequency behaviour of J1012+5307. Because of the inherent asymmetry resulting from the oblique traverse of sightline, each minimum in double notches can be modelled independently. Such a composed model reproduces the double notches of B1929+10 if the fitted function is the microscopic beam of curvature radiation in the orthogonal polarisation mode. These results confirm our view that some of the double components in radio pulsar profiles directly reveal the microscopic nature of the emitted radiation beam as the microbeam of curvature radiation polarised orthogonally to the trajectory of electrons.