Session 58 - Future of Antarctic Astrophysics.
Display session, Wednesday, June 10
Atlas Ballroom,

## [58.10] AST/RO Observations of [CI] in Galactic H\thinspace II Regions

M. Huang, T. M. Bania, A. Bolatto, R. A. Chamberlin, J. G. Ingalls, J. Jackson (Boston U.), A. A. Stark, A. P. Lane, M. Rumitz, R. W. Wilson (SAO), G. Wright (Lucent Tech.)

We present the results of a study of atomic carbon ( ^3P_1\to^3P_0) emission from Southern Hemisphere H \ \scriptstyle II regions using the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO).

One part of our H \ \scriptstyle II region sample consists of 49 compact, relatively isolated members of the Wilson et al. (1970) hydrogen radio recombination line (RRL) emission catalogue. Most [C \ \scriptstyle I \,] spectra of the sample show multiple emission components, and every H \ \scriptstyle II region has associated [C \ \scriptstyle I \,] emission near the RRL velocity. The mean linewidth of these [ C \ \scriptstyle I \,] components is 6.8 \pm 3.0 \, km s^-1; this cannot be explained by thermal broadening and indicates that turbulent broadening is important. RRL-associated [C \ \scriptstyle I \,] emission components are brighter than those not associated with H \ \scriptstyle II regions, which suggests that the [C \ \scriptstyle I \,] intensities are dominated by local heating.

The second part of our sample consists of 11 H \ \scriptstyle II regions from the Caswell and Haynes (1987) radio recombination line catalogue. We have observed fine-structure C^+ (157 \mum) emission using the Long Wavelength Spectrometer (LWS) on board the ISO satellite. We have also observed both CO J=4-3 and [C \ \scriptstyle I \,] emission using AST/RO, and H_91\alpha, H_92\alpha RRLs using the 140-foot radiotelescope at NRAO Greenbank. We discuss the physical properties of the H \ \scriptstyle II regions based on the different tracers of ionized, neutral, and molecular gas in the sample.

This research was supported 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.