Simulating radiative feedback and star cluster formation in GMCs: I.
  Dependence on gravitational boundedness
  Radiative feedback is an important consequence of cluster formation in Giant
Molecular Clouds (GMCs) in which newly formed clusters heat and ionize their
surrounding gas. The process of cluster formation, and the role of radiative
feedback, has not been fully explored in different GMC environments. We present
a suite of simulations which explore how the initial gravitational boundedness,
and radiative feedback, affect cluster formation. We model the early evolution
($<$ 5 Myr) of turbulent, 10$^6$ M$_{\odot}$ clouds with virial parameters
ranging from 0.5 to 5. To model cluster formation, we use cluster sink
particles, coupled to a raytracing scheme, and a custom subgrid model which
populates a cluster via sampling an IMF with an efficiency of 20\% per freefall
time. We find that radiative feedback only decreases the cluster particle
formation efficiency by a few percent. The initial virial parameter plays a
much stronger role in limiting cluster formation, with a spread of cluster
formation efficiencies of 37\% to 71\% for the most unbound to the most bound
model. The total number of clusters increases while the maximum mass cluster
decreases with an increasing initial virial parameter, resulting in steeper
mass distributions. The star formation rates in our cluster particles are
initially consistent with observations but rise to higher values at late times.
This suggests that radiative feedback alone is not responsible for dispersing a
GMC over the first 5 Myr of cluster formation.
