The secrets of the nearest starburst cluster: II. The present-day mass function in NGC 3603

Based on deep VLT/ISAAC JHK photometry, we have derived the present-day mass function of the central starburst cluster NGC 3603 YC (Young Cluster) in the giant HII region NGC 3603. The effects of field contamination, individual reddening, and a possible binary contribution are investigated. The MF slopes resulting from the different methods are compared, and lead to a surprisingly consistent cluster MF with a slope of Gamma = -0.9 +/- 0.15. Analyzing different radial annuli around the cluster core, no significant change in the slope of the MF is observed. However, mass segregation in the cluster is evidenced by the increasing depletion of the high-mass tail of the stellar mass distribution with increasing radius. We discuss the indications of mass segregation with respect to the changes observed in the binned and cumulative stellar mass functions, and argue that the cumulative function as well as the fraction of high- to low-mass stars provide better indicators for mass segregation than the MF slope alone. (abridged)