Slide
Abstract
To probe the role of hierarchical gas structures in massive star formation, we performed a uniform statistical analysis of 13 Galactic massive star-forming regions using the FUGIN CO survey. Applying a non-binary dendrogram to the position-position-velocity data at a common resolution of ~1 pc, we classified the structures into macroscopic trunks, internal leaves nested within them, and isolated structures, and compared their properties while controlling for regional differences. In representative regions, the trunks trace filaments, hub-filament systems, and cloud-cloud collisions. Across the sample, the trunks are extended, massive, and strongly bound reservoirs, while the leaves are denser and more tightly bound than isolated structures of similar size. Cross-matching with YSO and Hi-GAL clump catalogs, we find that, the leaves convert more of their gas into dense clumps without a corresponding increase in low-mass star formation. We interpret this as continuous accretion and mutual interactions sustained by the deep potential of the trunks, which may raise the characteristic fragmentation mass. To test this scenario, we are also performing numerical simulations of self-gravitating turbulent GMCs for direct comparison with the observations through synthetic observations.