Starburst--driven galactic outflows
  We propose a model of starburst--driven galactic outflows whose dynamics
depends on both radiation and thermal pressure. Standard models of thermal
pressure--driven winds fail to explain some key observations of outflows at low
and high redshift galaxies. We discuss a scenario in which radiation pressure
from massive stars in a stellar population drive a shell of gas and dust.
Subsequent supernova (SN) explosions from the most massive stars in this
population then drive stellar ejecta outward in a rarefied medium, making it
collide with the radiation pressure driven shell. The collision imparts renewed
momentum to the shell, and the resulting re-acceleration makes the shell
Rayleigh-Taylor unstable, fragmenting the shell. We show that the speed of
these ballistic fragments can explain some recently observed correlations in
Lyman break galaxies between wind speed, reddening and star formation rate.
