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Redshifted methanol absorption tracing infall motions of high-mass star formation regions

Yang, WJ, Menten, KM, Yang, AY, Wyrowski, F, Gong, Y, Ellingsen, SP ORCID: 0000-0002-1363-5457, Henkel, C, Chen, X and Xu, Y 2022 , 'Redshifted methanol absorption tracing infall motions of high-mass star formation regions' , Astronomy & Astrophysics, vol. 658 , pp. 1-21 , doi:

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Context: Gravitational collapse is one of the most important processes in high-mass star formation. Compared with the classic blue-skewed profiles, redshifted absorption against continuum emission is a more reliable method to detect inward motions within high-mass star formation regions.Aims: We aim to test if methanol transitions can be used to trace infall motions within high-mass star formation regions.Methods: Using the Effelsberg-100 m, IRAM-30 m, and APEX-12 m telescopes, we carried out observations of 37 and 16 methanol transitions towards two well-known collapsing dense clumps, W31C (G10.6−0.4) and W3(OH), to search for redshifted absorption features or inverse P-Cygni profiles.Results: Redshifted absorption is observed in 14 and 11 methanol transitions towards W31C and W3(OH), respectively. The infall velocities fitted from a simple two-layer model agree with previously reported values derived from other tracers, suggesting that redshifted methanol absorption is a reliable tracer of infall motions within high-mass star formation regions. Our observations indicate the presence of large-scale inward motions, and the mass infall rates are roughly estimated to be ≳10-3 M⊙ yr-1, which supports the global hierarchical collapse and clump-fed scenario.Conclusions: With the aid of bright continuum sources and the overcooling of methanol transitions leading to enhanced absorption, redshifted methanol absorption can trace infall motions within high-mass star formation regions hosting bright H II regions.

Item Type: Article
Authors/Creators:Yang, WJ and Menten, KM and Yang, AY and Wyrowski, F and Gong, Y and Ellingsen, SP and Henkel, C and Chen, X and Xu, Y
Keywords: stars: formation - ISM: kinematics and dynamics - ISM: individual objects: W3(OH) - ISM: individual objects: W31C(G10.6-0.4) - ISM: molecules - radio lines: ISM
Journal or Publication Title: Astronomy & Astrophysics
Publisher: E D P Sciences
ISSN: 0004-6361
DOI / ID Number:
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© W. J. Yang et al. 2022 Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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