Exploiting simultaneous multi-frequency observations to probe polar-cap processes

TL;DR

This paper discusses how simultaneous multi-frequency observations of pulsars can reveal details about the polar-cap processes, testing and exploiting the carousel model of sub-pulse drifting.

Contribution

It demonstrates that multi-frequency data can be used to probe the electrodynamics of the pulsar polar cap and test the carousel model's predictions.

Findings

Predicts observable effects in multi-frequency pulsar observations.

Provides methods to estimate physical quantities of the polar cap.

Suggests ways to interpret carousel-related phenomena.

Abstract

Sub-pulse drifting has been regarded as one of the most insightful aspects of the pulsar radio emission. The phenomenon is generally explained with a system of emission sub-beams rotating around the magnetic axis, originating from a carousel of sparks near the pulsar surface (the carousel model). Since the observed radio emission at different frequencies is generated at different altitudes in the pulsar magnetosphere, corresponding sampling of the carousel on the polar cap differs slightly in magnetic latitude. When this aspect is considered, it is shown here that the carousel model predicts important observable effects in multi-frequency or wide-band observations. Also presented here are brief mentions of how this aspect can be exploited to probe the electrodynamics in the polar cap by estimating various physical quantities, and correctly interpret various carousel related phenomena, in addition to test the carousel model itself.