right ascension range, compared to that of the central part of the field (Figure \[fig\_spatial\]a), are simply due to the decreasing angular coverage of the CCCP observation near the east and west boundaries (Figure \[fig\_spatial\]c).

X-ray Median Energy \[me\_contamination\_subsection\]
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The X-ray median energy statistic, $MedE$, is the most robust among the measured photometric quantities used to describe the spectral shapes of weak X-ray sources. $MedE$ is most effective as a surrogate for the absorption column, but if the absorption is independently known, it can give a rough measure of plasma temperature [@Feigelson05; @Getman10]. From the simulated spectra of the Carina contaminants (§ \[contaminants\_main\_section\]), we obtain histograms of $MedE$ for each of the three simulated contaminant classes and compare them with the observed CCCP sources in Figure \[fig\_me\]. Notice that the observed CCCP sources are mixture of objects from all four classes: PMS stars, foreground stars, background stars, and AGNs. A few important findings emerge.

1.  The three contaminant classes occupy mostly distinct ranges of $MedE$: 96% of the simulated foreground stars have very soft X-ray spectra with $0.7 < MedE < 1.1$ keV range; 81% of the simulated background stars are within the $1.1 < MedE < 1.5$ keV 