Hot Galactic Winds Constrained by the X-Ray Luminosities of Galaxies
  Galactic superwinds may be driven by very hot outflows generated by
overlapping supernovae within the host galaxy. We use the Chevalier & Clegg
(CC85) wind model and the observed correlation between X-ray luminosities of
galaxies and their SFRs to constrain the mass loss rates (\dot{M}_hot) across a
wide range of star formation rates (SFRs), from dwarf starbursts to
ultra-luminous infrared galaxies. We show that for fixed thermalization
efficiency and mass loading rate, the X-ray luminosity of the hot wind scales
as L_X ~ SFR^2, significantly steeper than is observed for star-forming
galaxies: L_X ~ SFR. Using this difference we constrain the mass-loading and
thermalization efficiency of hot galactic winds. For reasonable values of the
thermalization efficiency (<~ 1) and for SFR >~ 10 M_sun/yr we find that
\dot{M}_hot/SFR <~ 1, significantly lower than required by integrated
constraints on the efficiency of stellar feedback in galaxies, and potentially
too low to explain observations of winds from rapidly star-forming galaxies. In
addition, we highlight the fact that heavily mass-loaded winds cannot be
described by the adiabatic CC85 model because they become strongly radiative.
