Survival of Star-Forming Giant Clumps in High-Redshift Galaxies
  We investigate the effects of radiation pressure from stars on the survival
of the star-forming giant clumps in high-redshift massive disc galaxies, during
the most active phase of galaxy formation. The clumps, typically of mass
~10^8-10^9 Msun and radius ~0.5-1, are formed in the turbulent gas-rich discs
by violent gravitational instability and then migrate into a central bulge in
~10 dynamical times. We show that the survival or disruption of these clumps
under the influence of stellar feedback depends critically on the rate at which
they form stars. If they convert a few percent of their gas mass to stars per
free-fall time, as observed for all local star-forming systems and implied by
the Kennicutt-Schmidt law, they cannot be disrupted. Only if clumps convert
most of their mass to stars in a few free-fall times can feedback produce
significant gas expulsion. We consider whether such rapid star formation is
likely in high-redshift giant clumps.
