Conditions for supernovae driven galactic winds
  We point out that the commonly assumed condition for galactic outflows, that
supernovae (SNe) heating is efficient in the central regions of starburst
galaxies, suffers from invalid assumptions. We show that a large filling factor
of hot ($\ge 10^6$ K) gas is difficult to achieve through SNe heating,
irrespective of the initial gas temperature and density, and of its being
uniform or clumpy. We instead suggest that correlated supernovae from OB
associations in molecular clouds in the central region can drive powerful
outflows if the molecular surface density is $> 10^3$ M$_{\odot}$ pc$^{-2}$.
