ASTE CO(3-2) observations of M 83: Correlation between CO(3-2)/CO(1-0) ratios and star formation efficiencies

We have performed CO(J=3−2) emission observations with the Atacama Submillimeter Telescope Experiment (ASTE) toward the 5' × 5' (or 6.6 × 6.6 kpc at the distance D = 4.5 Mpc) region of the nearby barred spiral galaxy M 83. We successfully resolved the major structures, i.e., the nuclear starburst region, bar, and inner spiral arms in CO(J=3−2) emission at a resolution of 22'' (or 480 pc), showing a good spatial coincidence between CO(J=3−2) and 6 cm continuum emissions.