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Warm and Cold Molecular Gas in Galaxies

Daniel A. Dale·Kartik Sheth·George Helou·Michael W. Regan·Susanne Huttemeister
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Abstract

New and archival interferometric 12CO(1->0) datasets from six nearby galaxies are combined with H_2 2.122um and H-alpha maps to explore in detail the interstellar medium in different star-forming galaxies. We investigate the relation between warm (H_2 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 fnu(60um)/fnu(100um) 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.

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Daniel A. Dale, Kartik Sheth, George Helou, Michael W. Regan, Susanne Huttemeister. 2005-01-20. Warm and Cold Molecular Gas in Galaxies. https://doi.org/10.1086/429134

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