Population study for gama-ray emitting Millisecond Pulsars and Fermi unidentified sources

Abstract

The Fermi-LAT has revealed that rotation powered millisecond pulsars (MSPs) are a major contributor to the Galactic -ray source population. We discuss the -ray emission process within the context of the outer gap accelerator model, and use a Monte-Calro method to simulate the Galactic population of the -ray emitting MSPs. We find that the outer gap accelerator controlled by the magnetic pair-creation process is preferable in explaining the possible correlation between the -ray luminosity and the spin down power. Our Monte-Calro simulation implies that most of the -ray emitting MSPs are radio quiet in the present sensitivity of the radio survey, indicating that most of the -ray MSPs have been unidentified. We argue that the Galactic Fermi unidentified sources located at high latitudes should be dominated by MSPs, whereas the sources in the galactic plane are dominated by radio-quiet canonical pulsars.