ATLASGAL - properties of a complete sample of Galactic clumps

The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) is an unbiased 870 mu m submillimetre survey of the inner Galactic plane (vertical bar l vertical bar = 1000 M-circle dot at a heliocentric distance of 20 kpc) and includes representative samples of all of the earliest embedded stages of high-mass star formation. Here, we present the first detailed census of the properties (velocities, distances, luminosities and masses) and spatial distribution of a complete sample of similar to 8000 dense clumps located in the Galactic disc (5 degrees 10000 M-circle dot. We find a strong correlation between the fraction of clumps associated with massive stars and peak column density. The fraction is initially small at low column densities, but reaching 100 per cent for column densities above 10(23) cm(-2); there are no clumps with column densities above this value that are not already associated with massive star formation. All of the evidence is consistent with a dynamic view of star formation wherein the clumps form rapidly and are initially very unstable so that star formation quickly ensues