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Session 48 - Workshop on the Future of Antarctic Astrophysics - I.
Topical, Oral session, Wednesday, June 10
Presidio,
Submillimeter astronomy can only be pursued from extremely cold and dry sites, where the atmosphere contains a minimal amount of precipitable water. Water vapor measurements at the South Pole, in conjunction with submillimeter skydip measurements, show that the Antarctic Plateau provides the best submillimeter observing conditions on Earth. The 1.7-m diameter telescope of the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) has been exploiting these conditions for the past 3 years to study atomic carbon (CI) and J=4-3 CO emission in a broad range of physical environments in the Milky Way and Large Magellanic Cloud.
We have found from samples of [CI] emission throughout the plane of the Milky Way that [CI] arises primarily in the photodissociated skins of molecular clouds. A detection of the 492 GHz [CI] line in absorption allows the derivation of lower limits for the [CI] column density in cold foreground material in the Galactic disk. Comparison of the absorption data with the low-resolution COBE FIRAS [CI] emission line survey in the Galactic plane indicates that a substantial fraction of the atomic carbon in the interstellar medium has very low excitation and thus may be difficult to detect in emission. Observations of [CI] in the LMC indicate that photodissociation regions are enhanced in this low metallicity system.
This research was supported in part by the National Science Foundation under a cooperative agreement with the Center for Astrophysical Research in Antarctica (CARA), grant number NSF OPP 89-20223. CARA is a National Science Foundation Science and Technology Center.
