Hierarchical accretion flow from the G351 infrared dark filament to its central cores

¹ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
² Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
³ National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁴ Institute of Astronomy, National Tsing Hua University, Hsinchu 30013, Taiwan
⁵ Department of Earth and Planetary Sciences, Institute of Science Tokyo, Meguro, Tokyo 152-8551, Japan
⁶ National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁷ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK
⁸ Department of Astronomy, University of Florida, PO Box 112055, Gainesville, USA

^★ Corresponding author; beuther@mpia.de

Received: 25 October 2024
Accepted: 11 February 2025

Abstract

Context. Quantifying the accretion flow from large cloud scales down to individual protostars is a central ingredient to the understanding of (high-mass) star formation.

Aims. We characterize and quantify this multi-scale flow for a prototypical high-mass star-forming region.

Methods. In a multi-scale analysis from parsec to ∼50 au scales, we combined multiple single-dish and interferometric observations to study the gas flow from large-scale sizes of several parsec (Mopra) via intermediate-scale filamentary gas flows (ALMA-IMF) to the central cores (ALMA DIHCA and configuration 10 data). The highest-resolution multi-configuration ALMA dataset achieved a spatial resolution of 0.027″ × 0.022″ or 50 au.

Results. This multi-scale study allows us to follow the gas from the environment of the high-mass star-forming region (∼2 pc) via intermediate-scale (∼0.25 pc) filamentary gas flows down to the innermost cores within the central few 1000 au. The intermediatescale filaments connect spatially and kinematically to the larger-scale cloud as well as the innermost cores. We estimate a filamentary mass inflow rate around 10⁻³ M_⊙ yr⁻¹, feeding into the central region that hosts at least a dozen mm cores. While the flow from the cloud via the filaments down to 10⁴ au appears relatively ordered, within the central 10⁴ au the kinematic structures become much more complicated and disordered. We speculate that this is caused by the interplay of the converging infalling gas with feedback processes from the forming central protostars.

Conclusions. This multi-scale study characterises and quantifies the hierarchical gas flow from clouds down to the central protostars for a prototypical infrared dark cloud with several embedded cores at an unprecedented detail. While comparatively ordered gas flows are found over a broad range of scales, the innermost area exhibits more disordered structures, likely caused by the combination of inflow, outflow and cluster dynamical processes.