ABSTRACT AST 94-17968 Turner, Jean Interstellar gas provides the fuel for star formation, luminous star bursts, and active galactic nuclei, phenomena which are most apparent in galactic nuclei. Radio and millimeter wave emission line observations permit study of the distribution and dynamics of gas in galaxies. For this project, millimeter interferometric observations will be made of carbon monoxide (CO) in nearby galaxies. High resolution measurements near a galactic nucleus allow mapping the molecular gas at close to the resolution of individual molecular clouds (> 20 parsecs). From such mapped images, one can determine the mass of molecular gas, the orbits of molecular clouds, and from the orbits, how mass is distributed in the central regions. Previous work has shown, for example, that for many galaxies mapped in CO, more than half of the total mass within the inner few hundred parsecs is molecular gas. With multi-transition CO observations, one can infer cloud properties such as temperature and density and study how these properties vary with location in the galaxy. Finally, mapping the large-scale structure of the galactic disk in both CO and in the atomic hydrogen 21 cm line permits examination of the linkage between nuclear gas and disk gas.
