Supergiant Shells and Molecular Cloud Formation in the LMC
  We investigate the influence of large-scale stellar feedback on the formation
of molecular clouds in the Large Magellanic Cloud (LMC). Examining the
relationship between HI and 12CO(J=1-0) in supergiant shells (SGSs), we find
that the molecular fraction in the total volume occupied by SGSs is not
enhanced with respect to the rest of the LMC disk. However, the majority of
objects (~70% by mass) are more molecular than their local surroundings,
implying that the presence of a supergiant shell does on average have a
positive effect on the molecular gas fraction. Averaged over the full SGS
sample, our results suggest that ~12-25% of the molecular mass in supergiant
shell systems was formed as a direct result of the stellar feedback that
created the shells. This corresponds to ~4-11% of the total molecular mass of
the galaxy. These figures are an approximate lower limit to the total
contribution of stellar feedback to molecular cloud formation in the LMC, and
constitute one of the first quantitative measurements of feedback-triggered
molecular cloud formation in a galactic system.
