Characteristic scale of star formation – I. Clump formation efficiency on local scales
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We have used the ratio of column densities derived independently from the 850-μm continuum James Clerk Maxwell Telescope Plane Survey and the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey to produce maps of the dense-gas mass fraction (DGMF) in two slices of the Galactic plane centred at l= 30◦ and 40◦. The observed DGMF is a metric for the instantaneous clump formation efficiency (CFE) in the molecular gas. We split the two fields into velocity components corresponding to the spiral arms that cross them, and a two-dimensional power-spectrum analysis of the spiral-arm DGMF maps reveals a break in slope at the approximate size scale of molecular clouds. We interpret this as the characteristic scale of the amplitude of variations in the CFE and a constraint on the dominant mechanism regulating the CFE and, hence, the star formation efficiency in CO-traced clouds.
Eden , D J , Moore , T J T , Plume , R , Rigby , A J , Urquhart , J S , Marsh , K A , Peñaloza , C H , Clark , P C , Smith , M W L , Tahani , K , Ragan , S E , Thompson , M A , Johnstone , D , Parsons , H & Rani , R 2021 , ' Characteristic scale of star formation – I. Clump formation efficiency on local scales ' , Monthly Notices of the Royal Astronomical Society , vol. 500 , no. 1 , pp. 191-210 . https://doi.org/10.1093/mnras/staa3188
Monthly Notices of the Royal Astronomical Society
Copyright 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1093/mnras/staa3188.
DescriptionFunding: DJE is supported by an STFC postdoctoral grant (ST/R000484/1).
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