Source Contamination in X-ray Studies of Star-Forming Regions:
  Application to the Chandra Carina Complex Project
  We describe detailed simulations of X-ray-emitting populations to evaluate
the levels of contamination by both Galactic and extragalactic X-ray sources
unrelated to a star-forming region under study. For Galactic contaminations, we
consider contribution from main-sequence stars and giants (not including
cataclysmic variables and other classes of accretion-driven X-ray binary
systems) as they make the dominant contribution at the position of the Carina
Nebula. The simulations take into consideration a variety of technical factors
involving a Galactic population synthesis model, stellar X-ray luminosity
functions, Chandra telescope response, source detection methodology, and
possible spatial variations in the X-ray background and absorption through
molecular clouds. When applied to the 1.42 square-degree field of the Chandra
Carina Complex Project (CCCP), the simulations predict ~5000 contaminating
sources (1 source per square arcminute of the survey), evenly distributed
across the field. The results of the simulations are further employed in a
companion CCCP study to assign membership probabilities to individual sources.
