Large- and Small-Scale Feedback in the Starburst Canters of Galaxies
  The interplay between stellar populations and gas in local starburst galaxies is analyzed using images from the Hubble Space Telescope to map the ages of the young stellar components and to isolate the contribution of shocks on spatial scales ranging from a few tens of pc to ~1 kpc. The shocked gas represents a small fraction of the total ionized gas in these objects, yet it can have profound effects on the long-term evolution of the starburst, which may include the triggering of new star formation. 
Daniela Calzetti (STScI)