Gamma-rays from pulsars

Abstract

A mechanism for the production of gamma-rays in pulsars based on the 'outer gap' model of Cheng, Ruderman, and Sutherland (1976) is devised. It is shown that outer-gap breakdowns through curvature-radiation-pair-production cascades can explain the observed gamma-ray emission of pulsars. The corresponding gamma-ray spectrum and luminosity formulae are derived in terms of pulsar parameters. The conditions which govern the shape of the spectrum at high photon energies are discussed. The results are applied to the Crab and Vela pulsars, and a good agreement with the observations is achieved. Finally, a relation between the gamma-ray efficiency and the apparent pulsar age is obtained.