An ALMA study of hub-filament systems II.Quiescent filaments converging towards highly dynamic hubs

@misc{anderson2026alma,
  title = {{An ALMA study of hub-filament systems II.Quiescent filaments converging towards highly dynamic hubs}},
  author = {Michael Anderson and Nicolas Peretto and Sarah E. Ragan and Andrew J. Rigby and Adam Avison and Ana Duarte-Cabral and Gary A. Fuller and Yancy L. Shirley and Alessio Traficante and Gwenllian M. Williams},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2608.05650},
  eprint = {2608.05650},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.05650},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - An ALMA study of hub-filament systems II.Quiescent filaments converging towards highly dynamic hubs
AU  - Michael Anderson
AU  - Nicolas Peretto
AU  - Sarah E. Ragan
AU  - Andrew J. Rigby
AU  - Adam Avison
AU  - Ana Duarte-Cabral
AU  - Gary A. Fuller
AU  - Yancy L. Shirley
AU  - Alessio Traficante
AU  - Gwenllian M. Williams
PY  - 2026
DA  - 2026/10/16
PB  - arXiv
DO  - 10.48550/arxiv.2608.05650
UR  - https://arxiv.org/abs/2608.05650
AB  - Hub-filament systems are networks of converging interstellar filaments, often with active star formation at their centres, that may play an important role in high-mass star formation. In the first paper of this series, we found that the mass fraction that ends up in a clump's most massive core is significantly higher in IR-dark hubs than in IR-bright clumps, suggesting that the most-massive cores form early on. Such early massive core formation requires large inflow rates and dynamically active IR-dark clumps. We now present N_2H^+(J=1-0) observations of six IR-dark hub-filament systems mapped with ALMA 12m, 7m, and total power at 3'' resolution, to trace the kinematics of the dense gas. The data show intricate emission structures and complex spectra. To characterise their kinematics, we have developed mwydyn, a fully-automated, multiple velocity component, hyperfine line-fitting code. Our results reveal that the emission invariably consists of quiescent individual filaments in the outskirts that converge towards the hub centres where a systematic increase in velocity dispersion and number of components is observed. We also find that the distribution of centroid velocities is remarkably similar between clumps, despite spanning more than one order of magnitude in mass. We propose that our results are best explained by the mixing of gravitationally-driven multi-directional inflows, resulting in highly complex and dynamic hub centres. We also discuss the implications of the observed differentiated filament and hub gas kinematics in the context of the 3D morphology of hub-filament systems.
ER  -