Pulsar Emission Beam Geometry of Radio Broadband Arecibo Sources

TL;DR

This study analyzes the emission beam geometry of radio pulsars across a broad frequency range, revealing population trends and supporting models of emission evolution related to pair-formation geometries.

Contribution

It provides a comprehensive analysis of pulsar beam geometry over a wide frequency spectrum using the core/double-cone model, incorporating scattering effects and population trends.

Findings

Core and conal profiles cluster into distinct $P$-$$ populations.

Evidence supports evolution in pair-formation geometries affecting emission.

Profiles show frequency-dependent evolution consistent with theoretical models.

Abstract

We present radio pulsar emission beam analyses and models with the primary intent of examining pulsar beam geometry and physics over the broadest band of radio frequencies reasonably obtainable. We consider a set of well-studied pulsars that lie within the Arecibo sky. These pulsars stand out for the broad frequency range over which emission is detectable, and have been extensively observed at frequencies up to 4.5 GHz and down to below 100 MHz. We utilize published profiles to quantify a more complete picture of the frequency evolution of these pulsars using the core/double-cone emission beam model as our classification framework. For the low-frequency observations, we take into account measured scattering time-scales to infer intrinsic vs scatter broadening of the pulse profile. Lastly, we discuss the populational trends of the core/conal class profiles with respect to intrinsic parameters. We demonstrate that for this sub-population of pulsars, core and conal dominated profiles cluster together into two roughly segregated $P$-$\dot{P}$ populations, lending credence to the proposal that an evolution in the pair-formation geometries is responsible for core/conal emission and other emission effects such as nulling and mode-changing.