On the Spatial Distribution of Stellar Populations in the Large Magellanic Cloud

Abstract

We measure the angular correlation function of stars in a region of the Large Magellanic Cloud (LMC) that spans 20 × 15. We find that the correlation functions of stellar populations are represented well by exponential functions of the angular separation for separations between 2' and 40' (corresponding to ~30 and 550 pc for an LMC distance of 50 kpc). The inner boundary is set by the presence of distinct, highly correlated structures, which are the more familiar stellar clusters, and the outer boundary is set by the observed region's size and the presence of two principal centers of star formation within the region. We also find that the normalization and scale length of the correlation function changes systematically with the mean age of the stellar population. The existence of positive correlation at large separations (~300 pc), even in the youngest population, argues for large-scale hierarchical structure in current star formation. The evolution of the angular correlation toward lower normalizations and longer scale lengths with stellar age argues for the dispersion of stars with time. We show that a simple, stochastic, self-propagating star formation model is qualitatively consistent with this behavior of the correlation function.