GALACTIC  SUPERWINDS

                         by Dr. Sergiy Silich
                            INAOE, Mexico


Mechanical feedback from massive stars is one of the major drivers of 
galaxy evolution. In the extreme cases shock waves generated in the 
sites of violent star formation may punch through the interstellar 
medium and form channels for free gas ejection into the intergalactic 
space. The process that is known as a galactic superwind.

It is a common believe that superwinds at the early universe evolution
and at the present day epoch may be responsible for intergalactic medium
heating and enrichment by heavy elements and control host galaxies
chemical evolution. However starburst impact on the interstellar and 
intergalactic medium is highly dependent both on the host galaxy 
properties and the starburst parameters.

Several key problems related to this issue are discussed:

- WHAT IS THE MECHANICAL ENERGY INPUT RATE THAT IS REQUIRED TO EJECT 
  NEWLY PROCESSED METALS OR MOST OF THE ISM OUT OF THE HOST GALAXY? 

- WHAT IS THE EXPECTED GALACTIC SUPERWIND CHEMICAL COMPOSITION?

- HOW SUPERWIND OBSERVATIONAL PROPERTIES (X-RAY and Halpha
  LUMINOSITIES) DEPEND ON STARBURST PARAMETERS?

Our findings are then compared with a sample of star-forming
galaxies with known starburst parameters and with individual 
objects.