The spatial evolution of stellar structures in the Large Magellanic Cloud |
| |
| Authors: | Nate Bastian Mark Gieles Barbara Ercolano Rob Gutermuth |
| |
| Institution: | Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT;European Southern Observatory, Casilla 19001, Santiago 19, Chile;Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA |
| |
| Abstract: | We present an analysis of the spatial distribution of various stellar populations within the Large Magellanic Cloud (LMC). We combine mid-infrared selected young stellar objects, optically selected samples with mean ages between ∼9 and ∼1000 Myr and existing stellar cluster catalogues to investigate how stellar structures form and evolve within the LMC. For the analysis we use Fractured Minimum Spanning Trees, the statistical Q parameter and the two-point correlation function. Restricting our analysis to young massive (OB) stars, we confirm our results obtained for M33, namely that the luminosity function of the groups is well described by a power law with index −2, and that there is no characteristic length-scale of star-forming regions. We find that stars in the LMC are born with a large amount of substructure, consistent with a two-dimensional fractal distribution with dimension  and evolve towards a uniform distribution on a time-scale of ∼175 Myr. This is comparable to the crossing time of the galaxy, and we suggest that stellar structure, regardless of spatial scale, will be eliminated in a crossing time. This may explain the smooth distribution of stars in massive/dense young clusters in the Galaxy, while other, less massive, clusters still display large amounts of structure at similar ages. By comparing the stellar and star cluster distributions and evolving time-scales, we show that infant mortality of clusters (or 'popping clusters') has a negligible influence on the galactic structure. Finally, we quantify the influence of the elongation, differential extinction and contamination of a population on the measured Q value. |
| |
| Keywords: | Magellanic Clouds galaxies: star clusters galaxies: structure |
|
|
