The search for the sub-solar IMF in the Magellanic Clouds
Dimitrios A. Gouliermis, Alessandro Berton
Max-Planck-Institut für Astronomie, Koenigstuhl 17, D-69117 Heidelberg, Germany

The stellar Initial Mass Function (IMF) is a quantity which accounts for the distribution of the masses of stars when they are formed. The IMF is a very important physical quantity, which is directly linked to the formation of stars in individual stellar systems, but also in a galaxy as a whole. The general form of the IMF is such that, above about 0.5 M_\odot, the standard IMF is a power-law with an exponent G » -1.3 (the so-called Salpeter value), while at lower masses the IMF flattens with G » -0.3 (e.g. Kroupa 2002). Still, there is a lack of information on the low-mass end of the IMF, especially in galaxies other than our own, because of observational constraints, which do not allow us to detect the fainter stars with statistical significance. Only recently results from observations with the Wide Field Planetary Camera 2 on-board the Hubble Space Telescope (HST) on the low-mass stellar population in the LMC down to ~ 0.7 M_\odot have been released (Gouliermis et al. 2005). These results confirm systematic variations in the low-mass IMF earlier observed only in the Galaxy.

With ELTs "many of the massive young clusters throughout the Local Group would become reachable for direct imaging of resolved stellar populations, and we would begin to see the systematic variations in the IMF expected from some elementary theoretical considerations" (OPTICON: "The science Case for a European ELT"). Hence, a sizeable sample of young massive clusters for which the IMF can be determined, for the first time, over the entire stellar mass range, will be available. The Large and Small Magellanic Clouds (MCs) with their young compact star clusters provide a unique laboratory for such a study. We plan to make use of the most detailed, high-resolution imaging ever accomplished on young MC clusters, from the Advanced Camera for Surveys (available in the HST data archive), to construct simulated observations with a 100-m class telescope and to compare the results of the photometry from both space and ELT observations and its effect on the derived IMFs. This will demonstrate the nature of the advantages that will be introduced to crowded field photometry in close-by galaxies with ELTs.

Note: This is a research project under construction and has not yet reached any conclusive results by the date of the submission of this abstract.

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