High‐Energy Phase‐Averaged Spectra from Gamma‐Ray Pulsars

Abstract

We study high-energy radiation properties based on the vacuum outer gap model given by Zhang et al. In this model, the outer gap is sustained by a sufficient number of electron/positron pairs which are created through X-ray and high-energy photon interactions, forming a self-consistent outer gap. For a pulsar with known parameters such as period P, surface magnetic field Bp, and magnetic inclination angle α, the geometry of the outer gap (i.e., the transfield height and the radii of inner and outer boundaries of the outer gap) can be determined, and the radiation inside the outer gap along the kth field line which is tangent to the cylinder with a radius of R'L = kBRL is treated as a typical high-energy radiation, where RL = cP/2π is the light cylinder radius and kB is a parameter. We describe the calculation method of the γ-ray spectrum for a given γ-ray pulsar, calculate high-energy spectra for five known γ-ray pulsars (i.e., Geminga-like pulsars: Geminga and PSR B1055–52, and Vela-like pulsars: Vela, PSR B1951+32 and PSR B1706–44), and compare them with the observed data.