  Context. Recent Chandra observations of the Galactic center region (GCR) have
uncovered a population of faint discrete X-ray sources. A few theoretical works
have been made to investigate the nature of these sources. Aims. We examine the
contributions and luminosity functions of various kinds of candidate objects
which are proposed either by previous authors or by ourselves. Methods. We
conduct a population synthesis calculation based on Hurley et al.'s rapid
binary evolution code. Several candidate models, i.e. wind-accreting neutron
stars, intermediate polars, low mass X-ray binaries, young pulsars and massive
stars with strong winds, are incorporated into our calculation. We also take
the geometric effect of the accretion disk into account for Roche lobe overflow
X-ray binaries. Results. Our results show that neutron star low-mass X-ray
binaries contribute significantly to the observed sources. We also point out
that wind-accreting neutron stars contribute negligibly to these sources due to
propeller effect, and the intermediate polars play a minor role in accounting
for the faint X-ray sources in both Wang et al. and Muno et al. survey. It
should be mentioned that the majority of the sources in the survey field of
Wang et al. are still beyond our expectation.
