Constraining pulsar gap models with the light-curve and flux properties of the gamma-ray pulsar population

TL;DR

This study compares different pulsar emission models with Fermi LAT data, revealing that all models fail to fully reproduce observed gamma-ray pulsar properties and suggesting the need for more complex magnetic field structures.

Contribution

It provides a comprehensive comparison of inner and outer magnetosphere emission models against Fermi pulsar data, highlighting their limitations and the importance of magnetic field complexity.

Findings

All models fail to reproduce luminous and energetic pulsars.

Large dispersion in gamma-ray luminosity versus spin-down power.

Radio light-curve constraints improve model orientation fitting.

Abstract

We compare population synthesis results for inner and outer magnetosphere emission models with the various characteristics measured in the first LAT pulsar catalogue for both the radio-loud and radio-weak or radio-quiet gamma-ray pulsars. We show that all models fail to reproduce the observations: for each model there is a lack of luminous and energetic objects that suggest a non dipolar magnetic field structure or spin-down evolution. The large dispersion that we find in the simulated gamma-ray luminosity versus spin-down power relation does not allow to use the present trend seen in the Fermi data to distinguish among models. For each model and each Fermi detected pulsar, we have generated light curves as a function of obliquity and inclination angles. The theoretical curves were fitted to the observed one, using a maximum-likelihood approach, to derive the best-fit orientations and to compare how well each model can reproduce the data. Including the radio light-curve gives an additional key constraint to restrict the orientation space