Gas expulsion vs gas retention in young stellar clusters II: effects of
  cooling and mass segregation
  Gas expulsion or gas retention is a central issue in most of the models for
multiple stellar populations and light element anti-correlations in globular
clusters. The success of the residual matter expulsion or its retention within
young stellar clusters has also a fundamental importance in order to understand
how star formation proceeds in present-day and ancient star-forming galaxies
and if proto-globular clusters with multiple stellar populations are formed in
the present epoch. It is usually suggested that either the residual gas is
rapidly ejected from star-forming clouds by stellar winds and supernova
explosions, or that the enrichment of the residual gas and the formation of the
second stellar generation occur so rapidly, that the negative stellar feedback
is not significant. Here we continue our study of the early development of star
clusters in the extreme environments and discuss the restrictions that strong
radiative cooling and stellar mass segregation provide on the gas expulsion
from dense star-forming clouds. A large range of physical initial conditions in
star-forming clouds which include the star-forming cloud mass, compactness, gas
metallicity, star formation efficiency and effects of massive stars segregation
are discussed. It is shown that in sufficiently massive and compact clusters
hot shocked winds around individual massive stars may cool before merging with
their neighbors. This dramatically reduces the negative stellar feedback,
prevents the development of the global star cluster wind and expulsion of the
residual and the processed matter into the ambient interstellar medium. The
critical lines which separate the gas expulsion and the gas retention regimes
are obtained.
