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

TL;DR

This study analyzes the hierarchical structure of star formation in the 30 Doradus complex, revealing non-uniform, fractal-like distributions of young stars across various scales, supporting a hierarchical star formation scenario.

Contribution

It provides the first detailed analysis of hierarchical stellar structures in the 30 Doradus complex using VISTA data, highlighting the fractal nature of star formation.

Findings

Surface densities vary widely among young stars.

Stellar group sizes range from a few parsecs to over 100 parsecs.

The size distribution follows a power law with a fractal dimension of 1.6.

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($\Sigma\cdot$pc$^2$) $\lesssim$ $-$2.0 to log($\Sigma\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.