Disruption of giant molecular clouds and formation of bound star
  clusters under the influence of momentum stellar feedback
  Energetic feedback from star clusters plays a pivotal role in shaping the
dynamical evolution of giant molecular clouds (GMCs). To study the effects of
stellar feedback on the star formation efficiency of the clouds and the
dynamical response of embedded star clusters, we perform a suite of isolated
GMC simulations with star formation and momentum feedback subgrid models using
the moving-mesh hydrodynamics code \textsc{Arepo}. The properties of our
simulated GMCs span a wide range of initial mass, radius, and velocity
configurations. We find that the ratio of the final stellar mass to the total
cloud mass, $\epsilon_{\rm int}$, scales strongly with the initial cloud
surface density and momentum feedback strength. This correlation is explained
by an analytic model that considers force balancing between gravity and
momentum feedback. For all simulated GMCs, the stellar density profiles are
systematically steeper than that of the gas at the epochs of the peaks of star
formation, suggesting a centrally concentrated stellar distribution. We also
find that star clusters are always in a sub-virial state with a virial
parameter $\sim0.6$ prior to gas expulsion. Both the sub-virial dynamical state
and steeper stellar density profiles prevent clusters from dispersal during the
gas removal phase of their evolution. The final cluster bound fraction is a
continuously increasing function of $\epsilon_{\rm int}$. GMCs with star
formation efficiency smaller than 0.5 are still able to form clusters with
large bound fractions.
