Morphology of HII regions

We presented an automated method to delineate the boundaries of Galactic HII regions using dust column density maps from \textit{Herschel} Hi-GAL data. The algorithm transforms the image into polar coordinates and applies dynamic programming to identify closed, gradient-based contours. We applied this technique to a sample of large-angular-size sources from the WISE HII region catalog and successfully derived boundaries for 730 objects. We release a catalog for the 730 analyzed regions. This catalog includes morphological parameters (e.g., circularity, fractal dimension, compactness) and column density statistics (such as mean, coefficient of variation and Gini coefficient of density distribution) for both the interior and the immediate surroundings of each HII region.