The Luminosity Function of the Large Magellanic Cloud Globular Cluster NGC 1866

Abstract

We present Hubble Space Telescope VI photometry of the central region of the Large Magellanic Cloud cluster NGC 1866, reaching magnitudes as faint as V=27. We find evidence that the cluster luminosity function shows a strong dependence on the distance from the cluster center, with a clear deficiency of low-luminosity stars in the inner region. We discuss a global cluster luminosity function as obtained from stars from all parts of the investigated region, which appears in impressive agreement with the prediction from a Salpeter mass distribution. We also revisit the use of NGC 1866 as a probe for determining the efficiency of core overshooting and conclude that a definitive answer to this question is not possible from this cluster.