Mass functions of five young Large Magellanic Cloud star clusters

Abstract

BV CCD data of five young star clusters in LMCs are analyzed in order to determine their mass functions. The clusters span a range of about 10 to 100 Myr in age. Three different sets of theoretical stellar evolutionary tracks are used to convert the true luminosity functions (LFs) into mass functions (MFs); the effects of various parameters on the slope of the MFs are studied. In the mass range of 2 to 14 solar masses, the MF slopes of the four well-observed clusters are very similar. They can be well represented by a power law with an average slope of x = 1.1. For NGC 1711, 2004, and 2164, the MF slopes are almost the same in the two rings located at about 80 and 160 pixels from the cluster center. The correction for data incompleteness according to the procedure of Mateo (1988) makes the MFs steeper by 0.3 compared to this case. The average value of x = 1.1 is based on an assumed metallicity Z = 0.02. The MF slope does not depend significantly on the metallicity of the clusters as long as Z is between 0.02 and 0.004.