Probing ISM Structure in Trumpler 14 & Carina I Using The Stratospheric
  Terahertz Observatory 2
  We present observations of the Trumpler 14/Carina I region carried out using
the Stratospheric Terahertz Observatory 2 (STO2). The Trumpler 14/Carina I
region is in the west part of the Carina Nebula Complex, which is one of the
most extreme star-forming regions in the Milky Way. We observed Trumpler
14/Carina I in the 158 $\mu$m transition of [C\,{\sc ii}] with a spatial
resolution of 48$''$ and a velocity resolution of 0.17 km s$^{-1}$. The
observations cover a 0.25$^\circ$ by 0.28$^\circ$ area with central position
{\it l} = 297.34$^\circ$, {\it b} = -0.60$^\circ$. The kinematics show that
bright [C\,{\sc ii}] structures are spatially and spectrally correlated with
the surfaces of CO clouds, tracing the photodissociation region and ionization
front of each molecular cloud. Along 7 lines of sight that traverse Tr 14 into
the dark ridge to the southwest, we find that the [C\,{\sc ii}] luminosity from
the HII region is 3.7 times that from the PDR. In same los we find in the PDRs
an average ratio of 1:4.1:5.6 for the mass in atomic gas:dark-CO gas: molecular
gas traced by CO. Comparing multiple gas tracers including HI 21cm, [C\,{\sc
ii}], CO, and radio recombination lines, we find that the HII regions of the
Carina Nebula Complex are well-described as HII regions with one-side freely
expanding towards us, consistent with the champagne model of ionized gas
evolution. The dispersal of the GMC in this region is dominated by EUV
photoevaporation; the dispersal timescale is 20-30 Myr.
