The long lives of giant clumps and the birth of outflows in gas-rich
  galaxies at high redshift
  Star-forming disk galaxies at high redshift are often subject to violent disk
instability, characterized by giant clumps whose fate is yet to be understood.
The main question is whether the clumps disrupt within their dynamical
timescale (<50Myr), like molecular clouds in today's galaxies, or whether they
survive stellar feedback for more than a disk orbital time (~300Myr) in which
case they can migrate inward and help building the central bulge. We present
3.5-7pc resolution AMR simulations of high-redshift disks including
photo-ionization, radiation pressure, and supernovae feedback (Renaud et al.
2013, and Perret et al., this astro-ph issue). Our modeling of radiation
pressure determines the mass loading and initial velocity of winds from basic
physical principles. We find that the giant clumps produce steady outflow rates
comparable to and sometimes somewhat larger than their star formation rate,
with velocities largely sufficient to escape galaxy. The clumps also lose mass,
especially old stars, by tidal stripping, and the stellar populations contained
in the clumps hence remain relatively young (<=200Myr), as observed. The clumps
survive gaseous outflows and stellar loss, because they are wandering in
gas-rich turbulent disks from which they can re-accrete gas at high rates
compensating for outflows and tidal stripping, overall keeping realistic and
self-regulated gaseous and stellar masses. Our simulations produce gaseous
outflows with velocities, densities and mass loading consistent with
observations, and at the same time suggest that the giant clumps survive for
hundreds of Myr and complete their migration to the center of high-redshift
galaxies, without rapid dispersion and reformation of clumps.
