2001/07/16 by S. Huettemeister, Huettemeister, S., S. Aalto +1
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0107283
6 pages, 3 figures, to appear in `The central kpc of starbursts and AGN: the La Palma connection'', Eds. J.H. Knapen, J.E. Beckman, I. Shlosman and T.J. Mahoney, ASP conf. series, in press (2001)
arxiv created 2001/07/16 · openalex publication_date 2001/07/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The physical properties of molecular gas can be deduced from the analysis of line intensity ratios, most commonly of the CO isotopomers 12CO and 13CO. Barred galaxies, especially those with central starbursts, provide an excellent laboratory to study the changing properties of the gas as it approaches the center. Four galaxies (UGC2855, UGC2866, NGC7479 and NGC4123) are presented as examples of the results that can be obtained. Special attention is given to the case of (abnormally) high 12CO/13CO R12/13 line ratios (exceeding 20), which may indicate unusual gas properties. Qualitative scenarios for the structure of the ISM explaining a range of values of R12/13 are discussed.