Sub-kpc scale gas density structure and spiral-arm in barred spiral galaxy M83

ABSTRACT :
In this study, we investigated the relationship between the properties of diffuse and dense molecular gas distribution and galactic environments (spiral arms, interarm regions) using the GDH of the nearby face-on galaxy M83 (NGC 5236) observed at 12CO(𝐽=1–0). The results showed that the spatial structure of M83 and the distribution of diffuse and dense gases were consistent. The variance in the diffuse gas distribution was smaller than that of the dense gas. Additionally, it was found that the fraction of dense gas (𝑓′H) increased along the spiral arm. This is an important result, suggesting that dense gas forms from diffuse gas in the spiral arms.