[*disk-bearing*]{} PMS and other stars. Wider usage of IR colors and incorporation of IR-to-X-ray flux ratios (when applicable) will be considered in our future studies of other star forming regions.

Figure \[fig\_jmag\] compares $J$-band magnitude histograms among the $6,182$ CCCP sources with available 2MASS counterparts within the entire CCCP field of view (dashed lines) and the three simulated contamination populations (solid lines). $J$-band magnitudes for the foreground and background field stars are obtained directly from the Besançon model simulations; for the background stars, magnitudes are slightly increased for the absorption from the Carina molecular cloud. For the extragalactic contaminants, we produce an approximate distribution of $J$-band magnitudes using the relationship between the nominal (see §\[contaminants\_agn\_section\]) hard-band X-ray flux and $I$-band magnitude reported for the [*Chandra*]{} Deep Field North sources [Figure 7 in @Alexander01]. The $I$-band magnitudes are transformed to $J$-band magnitudes following Figure 11 in Alexander et al., accounting for an average combined visual absorption of $A_V \sim10-12$ mag through the Galactic disk in the direction of Carina and through the Carina molecular clouds. For better compatibility with the CCCP histograms, we also present (Figure \[fig\_jmag\]b) the histograms of $J$-band magnitudes for simulated foreground and background stars multiplied by the 