13CO/C18O Gradients across the Disks of Nearby Spiral Galaxies
We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure CO(1-0)/CO(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abun...
| Autores: | , , , , , , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/370016 |
| Acceso en línea: | http://hdl.handle.net/10261/370016 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxies: ISM ISM: molecules Radio lines: galaxies |
| Sumario: | We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure CO(1-0)/CO(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to chemistry or stellar nucleosynthesis effects. Resolved CO/CO gradients across normal galaxies have been rare due to the faintness of these lines. We find a mean CO/CO ratio of 6.0 ±0.9 for the central regions of our galaxies. This agrees well with results in the Milky Way, but differs from results for starburst galaxies (3.4 ± 0.9) and ultraluminous infrared galaxies (1.1 ± 0.4). In our sample, the CO/CO ratio consistently increases with increasing galactocentric radius and decreases with increasing star formation rate surface density. These trends could be explained if the isotopic abundances are altered by fractionation; the sense of the trends also agrees with those expected for carbon and oxygen isotopic abundance variations due to selective enrichment by massive stars. © 2017. The American Astronomical Society. All rights reserved |
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