Multi-scale dynamics in star-forming regions: the interplay between
  gravity and turbulence
  In this work we investigate the interplay between gravity and turbulence at
different spatial scales and in different density regimes. We analyze a sample
of 70 $\mu$m quiet clumps that are divided into three surface density bins and
we compare the dynamics of each group with the dynamics of their respective
filaments. The densest clumps form within the densest filaments on average, and
they have the highest value of the velocity dispersion. The kinetic energy is
transferred from the filaments down to the clumps most likely through a
turbulent cascade, but we identify a critical value of the surface density,
$\Sigma\simeq0.1$ g cm$^{2}$, above which the dynamics changes from being
mostly turbulent-driven to mostly gravity-driven. The scenario we obtain from
our data is a continuous interplay between turbulence and gravity, where the
former creates structures at all scales and the latter takes the lead when the
critical surface density threshold is reached. In the densest filaments this
transition can occur at the parsec, or even larger scales, leading to a global
collapse of the whole region and most likely to the formation of the massive
objects.
