C+ Emission from the Magellanic Clouds II. [CII] maps of star-forming
  regions LMC-N 11, SMC-N 66, and several others
  We study the 158 micron [CII] fine-structure line emission from star-forming
regions as a function of metallicity. We have measured and mapped the [CII]
emission from the very bright HII region complexes N 11 in the LMC and N 66 in
the SMC, as well as the SMC HII regions N 25, N 27, N 83/N 84, and N 88, with
the FIFI instrument on the Kuiper Airborne Observatory. In both the LMC and
SMC, the ratio of the [CII] line to the CO line and to the far-infrared
continuum emission is much higher than seen almost anywhere else, including
Milky Way star-forming regions and whole galaxies. In the low metallicity, low
dust-abundance environment of the LMC and the SMC, UV mean free path lengths
are much greater than those in the higher-metallicity Milky Way. The increased
photoelectric heating efficiencies cause significantly greater relative [CII]
line emission strengths. At the same time, similar decreases in PAH abundances
have the opposite effect, by diminishing photoelectric heating rates.
Consequently, in low-metallicity environments the relative [CII] strengths are
high but exhibit little further dependence on actual metallicity. Relative
[CII] strengths are slightly higher in the LMC than in the SMC, which has both
lower dust and lower PAH abundances.
