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Infall and outflow towards high-mass starless clump candidates

Pillai, T.G.S., Urquhart, J.S., Leurini, S., Zhang, Q., Traficante, A., Colombo, D., Wang, K., Gomez, L., Wyrowski, F. (2023) Infall and outflow towards high-mass starless clump candidates. Monthly Notices of the Royal Astronomical Society, 522 (3). pp. 3357-3366. ISSN 0035-8711. E-ISSN 1365-2966. (doi:10.1093/mnras/stad1073) (KAR id:101217)


The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact H II regions. While there are many examples of the three later stages, the very early stages have proved to be elusive. We follow-up a sample of 110 mid-infrared dark clumps selected from the ATLASGAL catalogue with the IRAM telescope in an effort to identify a robust sample of massive starless clumps. We have used the HCO+ and HNC (1-0) transitions to identify clumps associated with infall motion and the SiO (2-1) transition to identity outflow candidates. We have found blue asymmetric line profile in 65 per cent of the sample, and have measured the infall velocities and mass infall rates (0.6–36 × 10−3 M⊙ yr−1) for 33 of these clumps. We find a trend for the mass infall rate decreasing with an increase of bolometric luminosity to clump mass, i.e. star formation within the clumps evolves. Using the SiO 2-1 line, we have identified good outflow candidates. Combining the infall and outflow tracers reveals that 67 per cent of quiescent clumps are already undergoing gravitational collapse or are associated with star formation; these clumps provide us with our best opportunity to determine the initial conditions and study the earliest stages of massive star formation. Finally, we provide an overview of a systematic high-resolution ALMA study of quiescent clumps selected that allows us to develop a detailed understanding of earliest stages and their subsequent evolution.

Item Type: Article
DOI/Identification number: 10.1093/mnras/stad1073
Uncontrolled keywords: stars: early-type, stars: formation, ISM: clouds, ISM: kinematics and dynamics, ISM: molecules
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Funders: National Science Foundation (
National Natural Science Foundation of China (
Depositing User: James Urquhart
Date Deposited: 10 May 2023 07:45 UTC
Last Modified: 04 Mar 2024 15:23 UTC
Resource URI: (The current URI for this page, for reference purposes)

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