The VMC Survey XXII. Hierarchical Star Formation in the 30 Doradus-N158-N159-N160 Star-Forming Complex

Abstract

We study the hierarchical stellar structures in a $\sim$1.5 deg${}^2$ area covering the 30 Doradus-N158-N159-N160 star-forming complex with the VISTA Survey of the Magellanic Clouds. Based on the young upper main-sequence stars, we find that the surface densities cover a wide range of values, from log($\hat{I}\pounds \cdot$pc${}^2$) $\lesssim$ $-$2.0 to log($\hat{I}\pounds \cdot$pc${}^2$) $\gtrsim$ 0.0. Their distributions are highly non-uniform, showing groups that frequently have sub-groups inside. The sizes of the stellar groups do not exhibit characteristic values, and range continuously from several parsecs to more than 100 pc; the cumulative size distribution can be well described by a single power law, with the power-law index indicating a projected fractal dimension $D_2$ = 1.6 $\pm$ 0.3. We suggest that the phenomena revealed here support a scenario of hierarchical star formation. Comparisons with other star-forming regions and galaxies are also discussed.

11 pages, 7 figures. Accepted for publication in ApJ