The annular gap model for gamma-ray emission from young and millisecond pulsars

TL;DR

This paper employs the 3D annular gap model to simulate gamma-ray light curves of young and millisecond pulsars, successfully reproducing observed features and elucidating emission regions within their magnetospheres.

Contribution

It introduces a self-consistent 3D annular gap model for gamma-ray emission, providing detailed simulations for both young and millisecond pulsars that align with observations.

Findings

The model reproduces main features of observed pulsar light curves.

Emission regions differ between young and millisecond pulsars.

Higher energy emission originates from higher altitudes in the magnetosphere.

Abstract

Pulsed high energy radiation from pulsars is not yet completely understood. In this paper, we use the 3D self-consistent annular gap model to study light curves for both young and millisecond pulsars observed by the Fermi Gamma-ray Space Telescope. The annular gap can generate high energy emission for short-period pulsars. The annular gap regions are so large that they have enough electric potential drop to accelerate charged particles to produce gamma-ray photons. For young pulsars, the emission region is from the neutron star surface to about half of the light cylinder radius, and the peak emissivity is in the vicinity of the null charge surface. The emission region for the millisecond pulsars is located much lower than that of the young pulsars. The higher energy gamma-ray emission comes from higher altitudes in the magnetosphere. We present the simulated light curves for three young pulsars (the Crab, the Vela, the Geminga) and three millisecond pulsars (PSR J0030+0451, PSR J0218+4232, PSR J0437-3715) using the annular gap model. Our simulations can reproduce the main properties of observed light curves.