THE INITIAL MASS FUNCTION FOR MASSIVE STARS IN THE MAGELLANIC CLOUDS .3. LUMINOSITY AND MASS FUNCTIONS FOR 14 OB ASSOCIATIONS

We have used UBV photometry of stars in 14 associations in the Large a nd Small Magellanic Clouds (Hill, Madore, & Freedman) to derive lumino sity and mass functions for the most massive stars. The main-sequence luminosity functions for the associations are quite similar, having an average slope of s = 0.30 +/- 0.06. The mass functions for the associ ations have slopes that span similar ranges about a common mean for bo th the LMC and SMC and there is no strong evidence for a significant v ariation in the slopes from one association to another. Accordingly, m etal abundance does not appear to have a strong effect on the IMF, at least for the range in metallicity observed between the Magellanic Clo uds. The average slope of the IMF for the Magellanic Cloud association s is GAMMA = - 2.0 +/- 0.5 for M > 9 M.. The range in the derived slop es is more likely due to the large uncertainties associated with the c alculations of the mass functions, rather than to real variations in t he IMF. There may be some evidence for a decrease in the slope of the IMF at masses below 9 M., but incompleteness and the larger photometri c errors associated with the faintest stars make this conclusion tenta tive.