2022A&A...658A.192Y -
Astronomy and Astrophysics, volume 658A, 192-192 (2022/2-1)
Redshifted methanol absorption tracing infall motions of high-mass star formation regions.
YANG W.J., MENTEN K.M., YANG A.Y., WYROWSKI F., GONG Y., ELLINGSEN S.P., HENKEL C., CHEN X. and XU Y.
Abstract (from CDS):
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, 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 HII regions.
Abstract Copyright:
© W. J. Yang et al. 2022
Journal keyword(s):
stars: formation - ISM: kinematics and dynamics - ISM: individual objects: W3(OH) - ISM: individual objects: W31C(G10.6-0.4) - ISM: molecules - radio lines: ISM
Simbad objects:
20
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