THE SCALE HEIGHT AND RADIAL-DISTRIBUTION OF MOLECULAR GAS IN NGC-891

CO aperture synthesis observations at 2.3'' (106 pc) resolution are presented for the edge-on spiral galaxy NGC 891. Nine fields spaced 45'' apart along the plane of the galaxy are mosaicked to provide a complete, high-resolution image of the molecular gas out to 10 kpc radius. The aperture synthesis maps recover approximately 90% of the CO emission detected in single-dish measurements of NGC 891. The radial distribution of the CO emission is remarkably similar to that of our Galaxy-a nuclear disk component within R < 225 pc and a molecular ring at radii between 3 and 7 kpc. In the nucleus the gas mass is approximately 20% of the dynamical mass. The thickness (FWHM) of the CO emission is found to be 3.5'' (160 pc) in the galactic nucleus, increasing to 6'' (276 pc) at the edge of the galaxy.