| Abstract: We present a multi-scale analysis of molecular gas flows in the massive star-forming complex G305, focusing on how large filaments feed dense cores hosting ATOMS-selected infrared sources. Using Herschel dust temperature and H2 column density maps together with molecular line data tracing gas near −38 km s−1, we link parsec-scale cloud morphology to sub-parsec star-forming regions. Five ATOMS targets—IRAS 13079−6218, IRAS 13080−6229, IRAS 13111−6228, IRAS 13134−6242, and IRAS 13140−6226—lie in high column density filaments with H2 ≈ (0.5–3) × 10^22 cm−2 that converge into compact hubs.
The molecular gas shows continuous velocity fields and ordered gradients along the filaments, indicating structured inflow from >10 pc scales down to the immediate vicinity of the ATOMS sources. The most massive and evolved object, IRAS 13079−6218, sits at the junction of several filaments in the eastern cloud, coincident with higher dust temperatures and larger velocity dispersion, consistent with active accretion and strong stellar feedback. In contrast, sources in the western cloud are associated with cooler dust and simpler filaments, suggesting earlier evolutionary stages. The alignment of filament intersections, dense gas peaks, and compact and extended H II regions indicates that ionizing radiation from massive stars both disrupts and compresses the molecular gas, channeling inflow along the remaining filaments.
These results support a hierarchical accretion scenario in which large molecular clouds funnel material through filamentary networks into dense hubs, enabling high-mass star formation. G305 thus provides a key test bed for how global cloud dynamics and stellar feedback regulate mass accumulation from cloud to core scales. |
