The Physical Structure of Supergiant Shells in the LMC AAS 197, January 2001 Session 112.
Supergiant shells are the largest coherent interstellar structures observed in galaxies.
They are thought to be the result of fast stellar winds and multiple supernova explosions from massive stars in multiple OB associations. It may be possible for these structures to break out of the gaseous disk and vent hot gas into the galactic halo. We have observed two LMC supergiant shells, LMC 1 and LMC 4, to better understand these objects. These observations triple our sample of kinematic studies of LMC supergiant shells and provide insight into the controversy about the expansion of supergiant shells. We find no evidence for coherent expansion in either of these supergiant shells.