The Initial Mass Function toward the Low‐Mass End in the Large Magellanic Cloud withHubble Space TelescopeWFPC2 Observations

We present V and I equivalent HST/WFPC2 photometry of two areas in the LargeMagellanic Cloud: The southern part of the stellar association LH 52, locatedon the western edge of the super-shell LMC 4, and a field between twoassociations, which is located on the southwestern edge of the shell, and whichaccounts for the general background field of the galaxy. The HST/WFPC2observations reach magnitudes as faint as V=25 mag, much deeper than have beenobserved earlier in stellar associations in the LMC. We determine the MF formain-sequence stars in the areas. Its slope (Gamma) in both areas is steeperfor stars with masses M < 2 M_solar (-4 < Gamma < -6), compared with stars of M> 2 M_solar (-1 < Gamma < -2). Thus, as far as the field of the LMC concernsthe MF does not have a uniform slope throughout its observed mass range. The MFof the general field of the LMC was found previously to be steeper than the MFof a stellar association for massive stars with M > 5 M_solar. We conclude thatthis seems to be also the case toward lower masses down to M ~ 1 M_solar. Ourdata allow to construct the field-subtracted, incompleteness-corrected,main-sequence MF of the southwestern part of the young stellar association LH52, which accounts for the Initial Mass Function (IMF) of the system. Its meanslope is found to be comparable, but still more shallow than a typical SalpeterIMF (Gamma = -1.12 +/- 0.24) for masses down to ~ 1 M_solar. We foundindications that the IMF of the association probably is ``top-heavy'', due tothe large number of intermediate-mass stars in the field of the system, whilethe general LMC field is found to be responsible for the low-mass population,with M < 2 M_solar, observed in both fields.Comment: 15 pages, 9 figures, accepted for publication in Ap