ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions – XI. From inflow to infall in hub-filament systems
Jianwen Zhou, Tie Liu, Neal J. Evans, Guido Garay, P. F. Goldsmith, Gilberto C. Gómez, Enrique Vazquez‐Semadeni, Hongli Liu, Amelia M. Stutz, Ke Wang, M. Juvela, Jinhua He, Di Li, L. Bronfman, Xunchuan Liu, Fengwei Xu, Anandmayee Tej, L. K. Dewangan, Shanghuo Li, Siju Zhang, Chao Zhang, Zhiyuan Ren, Ken’ichi Tatematsu, Pak Shing Li, Chang Won Lee, Tapas Baug, Sheng‐Li Qin, Yuefang Wu, Yaping Peng, Yong Zhang, Rong Liu, Qiuyi Luo, Jixing Ge, Anindya Saha, Chakali Eswaraiah, Qizhou Zhang, Kee‐Tae Kim, Isabelle Ristorcelli, Zhi-Qiang Shen, Jin-Zeng Li
Abstract
ABSTRACT We investigate the presence of hub-filament systems in a large sample of 146 active proto-clusters, using H13CO+ J = 1-0 molecular line data obtained from the ATOMS survey. We find that filaments are ubiquitous in proto-clusters, and hub-filament systems are very common from dense core scales (∼0.1 pc) to clump/cloud scales (∼1–10 pc). The proportion of proto-clusters containing hub-filament systems decreases with increasing dust temperature (Td) and luminosity-to-mass ratios (L/M) of clumps, indicating that stellar feedback from H ii regions gradually destroys the hub-filament systems as proto-clusters evolve. Clear velocity gradients are seen along the longest filaments with a mean velocity gradient of 8.71 km s−1 pc−1 and a median velocity gradient of 5.54 km s−1 pc−1. We find that velocity gradients are small for filament lengths larger than ∼1 pc, probably hinting at the existence of inertial inflows, although we cannot determine whether the latter are driven by large-scale turbulence or large-scale gravitational contraction. In contrast, velocity gradients below ∼1 pc dramatically increase as filament lengths decrease, indicating that the gravity of the hubs or cores starts to dominate gas infall at small scales. We suggest that self-similar hub-filament systems and filamentary accretion at all scales may play a key role in high-mass star formation.