JHKs photometry of RCW 36 stars

Statistical comparisons of color-magnitude diagrams were performed between RCW 36 and a control field, also obtained using HAWK-I under the same mode, to assign membership weights for the sources in our field. Mass estimates to individual sources were also derived through comparison with model isochrones in order to determine the IMF using the membership weights. We found a new distance of 954+/-40pc.

We determined the IMF for RCW ,36 down to ~0.03M_{sun}_, characterized by a broken power law (dN/dM{prop.to}M^-alpha^ with alpha=1.62+/-0.03 (0.20M_{sun}_-20M_{sun}_) and alpha=0.46+/-0.14 (0.03M_{sun}_-0.20M_{sun}_). We also determined the star-BD ratio to be 2-5, in agreement with other Galactic clusters. Lastly, through a study of the differences in the IMF within and outside 0.2pc and the cumulative mass distributions for low-mass and intermediate to high- mass sources, we also detected signs of possible mass segregation within RCW 36, which should be primordial.

RCW 36 shares many characteristics with other young massive clusters, such as a shallower than Salpeter high-mass slope and the possibility of mass segregation. The flatter lower-mass regime of the IMF is similar to most Galactic clusters. The star-BD ratio is also in line with the observed values in other clusters, independent of their inherent properties.