Young stellar structures in NGC 6503

We apply a contour-based map analysis technique and identify in the stellar surface density map 244 distinct star-forming structures at various levels of significance. These stellar complexes are found to be organized in a hierarchical fashion with 95 percent being members of three dominant super-structures located along the star-forming ring.

The size distribution of the identified structures and the correlation between their radii and numbers of stellar members show power-law behaviours, as expected from scale-free processes. The self-similar distribution of young stars is further quantified from their autocorrelation function, with a fractal dimension of ~1.7 for length-scales between ~20pc and 2.5kpc. The young stellar radial distribution sets the extent of the star-forming ring at radial distances between 1 and 2.5kpc.