The pulsar contribution to the diffuse galactic gamma-ray emission

Abstract

Here we investigate to what extent unresolved \gr pulsars contribute to the galactic diffuse emission, and further whether unresolved \gr pulsars can be made responsible for the excess of diffuse galactic emission above 1 GeV which has been observed by EGRET. Our analysis is based only on the properties of the six pulsars which have been identified in the EGRET data, and is independent of choice of a pulsar emission model. We find that pulsars contribute very little to the diffuse emission at lower energies, whereas above 1 GeV they can account for 25% of the observed intensity in selected regions for a reasonable number of directly observable \gr pulsars ($\sim$12). While the excess above 1 GeV \gr energy is observed at least up to six or eight degrees off the plane, the pulsar contribution would be negligible there. Thus pulsars do significantly contribute to the diffuse galactic $\gamma$-ray emission above 1 GeV, but they can not be made responsible for all the discrepancy between observed intensity and model predictions in this energy range.Comment: 5 pages, Proceedings of the 4th Compton Symposiu