Constraining viewing geometries of pulsars with single-peaked gamma-ray profiles using a multiwavelength approach

TL;DR

This study uses multiwavelength data and geometric modeling to constrain the viewing geometries of gamma-ray pulsars with single-peaked profiles, providing independent verification and detailed insights into pulsar emission geometries.

Contribution

It introduces a geometric emission code applied to Fermi LAT and radio light curves to independently constrain pulsar viewing angles, complementing previous polarization-based methods.

Findings

Consistent results with previous polarization constraints

Small differences found in some pulsars' geometries

Derived flux correction factors with errors

Abstract

Since the launch of the Large Area Telescope (LAT) on board the Fermi spacecraft in June 2008, the number of observed gamma-ray pulsars has increased dramatically. A large number of these are also observed at radio frequencies. Constraints on the viewing geometries of 5 of 6 gamma-ray pulsars exhibiting single-peaked gamma-ray profiles were derived using high-quality radio polarization data (Weltevrede et al., 2010). We obtain independent constraints on the viewing geometries of 6 by using a geometric emission code to model the Fermi LAT and radio light curves (LCs). We find fits for the magnetic inclination and observer angles by searching the solution space by eye. Our results are generally consistent with those previously obtained (Weltevrede et al., 2010), although we do find small differences in some cases. We will indicate how the gamma-ray and radio pulse shapes as well as their relative phase lags lead to constraints in the solution space. Values for the flux correction factor corresponding to the fits are also derived (with errors).