(J − H) / (H − K) color–color diagram of sources detected in the JHKs bands in the CrW region. The sequences of dwarfs (solid curve) and giants (thick dashed curve) are from Bessell & Brett (1988). The dotted line represents the locus of T Tauri stars (Meyer et al. 1997). Parallel dashed straight lines represent the reddening vectors (Cohen et al. 1981). The crosses on the dashed lines are separated by A_V = 5 mag. YSOs are also shown. Open magenta squares = Spitzer; filled magenta circles = Hα; filled squares = X-ray emitting WTTSs (green = XMM-Newton, blue = Chandra); open red triangles = CTTSs and open green circles = probable NIR-excess sources (see text for the classification scheme).