Massive outflows associated with ATLASGAL clumps
  We have undertaken the largest survey for outflows within the Galactic Plane
using simultaneously observed 13CO and C18O data. 325 out of a total of 919
ATLASGAL clumps have data suitable to identify outflows, and 225 (69+-3%) of
them show high velocity outflows. The clumps with detected outflows show
significantly higher clump masses (M_{clump}), bolometric luminosities
(L_{bol}), luminosity-to-mass ratios (L_{bol}/M_{clump}) and peak H_2 column
densities (N_{H_2}) compared to those without outflows. Outflow activity has
been detected within the youngest quiescent clump (i.e.,70um weak) in this
sample and we find that the outflow detection rate increases with
M_{clump},L_{bol},L_{bol}/M_{clump} and N_{H_2},approaching 90% in some
cases(uchii regions=93+-3%;masers=86+-4%;hchii regions=100%). This high
detection rate suggests that outflows are ubiquitous phenomena of massive star
formation. The mean outflow mass entrainment rate implies a mean accretion rate
of ~10^{-4}M_\odot\,yr^{-1}, in full agreement with the accretion rate
predicted by theoretical models of massive star formation. Outflow properties
are tightly correlated with M_{clump},L_{bol} and L_{bol}/M_{clump},and show
the strongest relation with the bolometric clump luminosity. This suggests that
outflows might be driven by the most massive and luminous source within the
clump. The correlations are similar for both low-mass and high-mass outflows
over 7 orders of magnitude, indicating that they may share a similar outflow
mechanism. Outflow energy is comparable to the turbulent energy within the
clump, however, we find no evidence that outflows increase the level of clump
turbulence as the clumps evolve. This implies that the origin of turbulence
within clumps is fixed before the onset of star formation.
