From Gas to Stars in Energetic Environments: Dense Gas Clumps in the 30
  Doradus Region Within the Large Magellanic Cloud
  We present parsec scale interferometric maps of HCN(1-0) and HCO$^{+}$(1-0)
emission from dense gas in the star-forming region 30 Doradus, obtained using
the Australia Telescope Compact Array. This extreme star-forming region,
located in the Large Magellanic Cloud (LMC), is characterized by a very intense
ultraviolet ionizing radiation field and sub-solar metallicity, both of which
are expected to impact molecular cloud structure. We detect 13 bright, dense
clumps within the 30 Doradus-10 giant molecular cloud. Some of the clumps are
aligned along a filamentary structure with a characteristic spacing that is
consistent with formation via the varicose fluid instability. Our analysis
shows that the filament is gravitationally unstable and collapsing to form
stars. There is a good correlation between HCO$^{+}$ emission in the filament
and signatures of recent star formation activity including H$_{2}$O masers and
young stellar objects (YSOs). YSOs seem to continue along the same direction of
the filament toward the massive compact star cluster R136 in the southwest. We
present detailed comparisons of clump properities (masses, linewidths, sizes)
in 30Dor-10 to those in other star forming regions of the LMC (N159, N113,
N105, N44). Our analysis shows that the 30Dor-10 clumps have similar mass but
wider linewidths and similar HCN/HCO$^{+}$ (1-0) line ratios as clumps detected
in other LMC star-forming regions. Our results suggest that the dense molecular
gas clumps in the interior of 30Dor-10 are well-shielded against the intense
ionizing field that is present in the 30Doradus region.
