Source Contamination in X-ray Studies of Star-Forming Regions: Application to the Chandra Carina Complex Project

TL;DR

This study uses detailed simulations to estimate and analyze the level of contamination by unrelated Galactic and extragalactic X-ray sources in star-forming region studies, specifically applied to the Chandra Carina Complex Project.

Contribution

It introduces a comprehensive simulation framework to quantify contamination levels in X-ray surveys of star-forming regions, aiding in accurate source classification.

Findings

Approximately 5000 contaminating sources predicted in the CCCP field.

Contamination is evenly distributed across the survey area.

Simulations assist in assigning membership probabilities to X-ray sources.

Abstract

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.