University of Hertfordshire

Massive outflows associated with ATLASGAL clumps

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Original languageEnglish
Article number3
JournalAstrophysical Journal, Supplement Series
Journal publication date1 Mar 2018
Early online date21 Feb 2018
Publication statusPublished - 1 Mar 2018


We have undertaken the largest survey for outflows within the Galactic plane using simultaneously observed 13COand C18O data. Out of a total of 919 ATLASGAL clumps, 325 have data suitable to identify outflows, and 225(69% ± 3%) show high-velocity outflows. The clumps with detected outflows show significantly higher clumpmasses (Mclump), bolometric luminosities (Lbol), luminosity-to-mass ratios (Lbol Mclump), and peak H2 columndensities (NH2) compared to those without outflows. Outflow activity has been detected within the youngestquiescent clump (i.e., 70 mm weak) in this sample, and we find that the outflow detection rate increases withMclump, Lbol, Lbol Mclump, and NH2, approaching 90% in some cases (UC H II regions=93% ± 3%;masers=86% ± 4%; HC H II regions=100%). This high detection rate suggests that outflows are ubiquitousphenomena of massive star formation (MSF). The mean outflow mass entrainment rate implies a mean accretionrate of ∼ - -10 M⊙ yr 4 1, in full agreement with the accretion rate predicted by theoretical models of MSF. Outflowproperties are tightly correlated with Mclump, Lbol, and Lbol Mclump and show the strongest relation with thebolometric clump luminosity. This suggests that outflows might be driven by the most massive and luminoussource within the clump. The correlations are similar for both low-mass and high-mass outflows over 7 orders ofmagnitude, indicating that they may share a similar outflow mechanism. Outflow energy is comparable to theturbulent energy within the clump; however, we find no evidence that outflows increase the level of clumpturbulence as the clumps evolve. This implies that the origin of turbulence within clumps is fixed before the onsetof star formation.


This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. Under embargo until 21 February 2019. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at

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