Statistical Properties of High‐Energy Radiation from Young Pulsars

Abstract

We study the statistical properties of young pulsars with ages of <= 10(6) yr using the Monte Carlo method on the frame of a revised outer gap model. In our simulations, we first compare the simulated radio-loud pulsars with the observed ones in the ATNF Pulsar Catalogue, in which nine radio surveys are included. On the basis of consistency between the simulated and the observed young pulsars, we further simulate possible gamma-ray pulsars based on our outer gap model. In this model, geometric effects have been taken into account, and the high-energy radiation of a pulsar depends on period (P), magnetic field (B), and magnetic inclination angle (alpha). We take the gamma-ray beaming selection effects into account and study the statistical properties of gamma-ray pulsars with energy fluxes above the detectable threshold fluxes. For the EGRET detector, we predict that there may be similar to 8 radio-loud and similar to 24 radio-quiet gamma-ray pulsars if we take the neutron star birthrate to be 1.5 per century. For GLAST, we expect similar to 78 and similar to 740 radio-loud and radio-quiet gamma-ray pulsars. Most of the young gamma-ray pulsars are concentrated at the Galactic plane. We compared the energy fluxes of the simulated gamma-ray pulsars with those of low-latitude unidentified EGRET gamma-ray sources, indicating that the majority of these unidentified sources have pulsar origin.