Geometric modelling of radio and gamma-ray light curves of 6 Fermi LAT pulsars

TL;DR

This paper models radio and gamma-ray light curves of six Fermi LAT pulsars using geometric emission codes to constrain their viewing geometries and magnetic inclinations, providing insights into pulsar emission regions.

Contribution

It introduces a geometric modeling approach to fit radio and gamma-ray light curves of pulsars, offering independent constraints on their viewing geometries and emission altitudes.

Findings

Consistent viewing angle constraints with previous studies.

Identified differences in some pulsars' geometries.

Potential to estimate radio emission altitudes.

Abstract

The Fermi Large Area Telescope (LAT) has recently reported the detection of pulsed gamma-rays from 6 young pulsars (J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825), all exhibiting single-peaked pulse profiles (Weltevrede et al., 2010). High-quality radio polarization data are also available for 5 of these pulsars, allowing derivation of constraints on their viewing geometries. We obtain independent constraints on the viewing geometries of these pulsars by using a geometric pulsar emission code to model the Fermi LAT and radio light curves. We find fits for the magnetic inclination and observer angles alpha and zeta with typical errors of ~ 5deg. Our results are generally consistent with those obtained by Weltevrede et al. (2010), although we do find differences in some cases. Our model may lastly provide a framework to constrain the radio emission altitude.