Warm and Cold Molecular Gas in Galaxies
نویسندگان
چکیده
New and archival interferometric 12CO(1→0) datasets from six nearby galaxies are combined with H2 2.122 μm and Hα maps to explore in detail the interstellar medium in different star-forming galaxies. We investigate the relation between warm (H2 at T ∼ 2000 K) and cold (CO at T ∼ 50 K) molecular gas from 100 pc to 2 kpc scales. On these scales, the ratio of warm-to-cold molecular hydrogen correlates with the fν(60μm) fν(100μm) ratio, a ratio that tracks the star formation activity level. This result also holds for the global properties of galaxies from a much larger sample drawn from the literature. The trend persists for over three orders of magnitude in the mass ratio, regardless of source nuclear activity. Subject headings: galaxies: ISM — infrared: galaxies — radio lines: galaxies
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