The contribution of pulsars to diffuse gamma-rays in the Large Magellanic Cloud

Abstract

We study the contribution of young pulsars, with characteristic ages of less than 106 yr, to the diffuse γ-ray emission from the Large Magellanic Cloud (LMC). Based on the outer gap model for γ-ray emission proposed by Zhang & Cheng and pulsar properties in the LMC given by Hartmann, Brown & Schnepf, we simulate the properties of the young pulsars in the LMC. We show that γ-rays produced by the pulsars in the LMC may make an important contribution to the diffuse γ-rays in the LMC, especially in the high-energy range. We calculate the γ-ray energy spectrum of the pulsars in the LMC and show that the γ-ray component contributed by the pulsars to the diffuse γ-rays in the high-energy range (above ∼1 GeV) becomes dominant. We expect that none of the young pulsars should be detectable as an individual point source of γ-ray emission by EGRET. We also expect that pulsar contribution above ∼1 GeV in the SMC is very important.