The ${}^{13}\mathrm{CO}(2{-}1)/^{12}\mathrm{CO}(2{-}1)$ Line Ratio from 100 Molecular Clouds in the Large Magellanic Cloud
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2026
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| _version_ | 1866910226540658688 |
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| author | Kalra, Dia Rosolowsky, Erik Leroy, Adam Indebetouw, Remy |
| author_facet | Kalra, Dia Rosolowsky, Erik Leroy, Adam Indebetouw, Remy |
| contents | We analyze the line ratio of the $^{13}$CO (2-1) to $^{12}$CO (2-1) rotational transitions observed from new ALMA observations of 100 Giant Molecular Clouds (GMCs) that span the Large Magellanic Cloud. We measure a median line ratio of $^{13}\mathrm{CO}(2{-}1)/^{12}\mathrm{CO}(2{-}1) = 0.078$ with $68\%$ of the sample falling between 0.058 and 0.107. A regression analysis confirms a nearly linear relationship across two orders of magnitude in line luminosity. Moreover, we find that the inclusion of $(L_{\text{FIR}})$ from Young Stellar Objects as a predictor variable of the line ratio significantly improves the quality of the fit, with clouds hosting IR-bright YSOs having relatively brighter $^{13}$CO emission. This analysis indicates that active star forming molecular clouds have different internal conditions than more quiescent clouds. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_17024 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The ${}^{13}\mathrm{CO}(2{-}1)/^{12}\mathrm{CO}(2{-}1)$ Line Ratio from 100 Molecular Clouds in the Large Magellanic Cloud Kalra, Dia Rosolowsky, Erik Leroy, Adam Indebetouw, Remy Astrophysics of Galaxies We analyze the line ratio of the $^{13}$CO (2-1) to $^{12}$CO (2-1) rotational transitions observed from new ALMA observations of 100 Giant Molecular Clouds (GMCs) that span the Large Magellanic Cloud. We measure a median line ratio of $^{13}\mathrm{CO}(2{-}1)/^{12}\mathrm{CO}(2{-}1) = 0.078$ with $68\%$ of the sample falling between 0.058 and 0.107. A regression analysis confirms a nearly linear relationship across two orders of magnitude in line luminosity. Moreover, we find that the inclusion of $(L_{\text{FIR}})$ from Young Stellar Objects as a predictor variable of the line ratio significantly improves the quality of the fit, with clouds hosting IR-bright YSOs having relatively brighter $^{13}$CO emission. This analysis indicates that active star forming molecular clouds have different internal conditions than more quiescent clouds. |
| title | The ${}^{13}\mathrm{CO}(2{-}1)/^{12}\mathrm{CO}(2{-}1)$ Line Ratio from 100 Molecular Clouds in the Large Magellanic Cloud |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2605.17024 |