Tony Wong

5.12. High-resolution CO (1-0) observations of the ringed galaxy NGC 4736

It is well known that the radial distributions of atomic and molecular gas differ markedly in spiral galaxies, including our own (e.g. Burton & Gordon 1978, Sofue et al. 1995). We have recently begun a program to obtain multifrequency observations of several nearby galaxies in order to determine whether H I is needed to replenish the H 2 consumed by star formation and, if so, how this might be accomplished. Here we present initial results on the nearby RSab galaxy NGC 4736, known for its bright ring of H II regions and recently shown to have a central stellar bar (Mollenhoff et al. 1995). We have mapped the distribution of CO (1-0) emission within r =1′ (1.8 kpc at D =6.2 Mpc) with the BIMA interferometer at ~5″ resolution, and added data from the NRAO 12-m telescope to recover zero-spacing information.