JCMT Mapping of CO(3-2) in the Circumnuclear Region of M31
| Autor: | Li, ZN, Li, ZY, Zhou, P, Gao, Y, Jiang, XJ, Dong, H. |
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| Přispěvatelé: | National Key Research and Development Program (China), National Natural Science Foundation of China |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
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| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1147-3010 |
| Popis: | We present a survey of CO(3-2) molecular line emission in the circumnuclear region of M31 with the James Clerk Maxwell Telescope (JCMT), aiming to explore the physical conditions of the molecular gas. Significant CO(3-2) lines are detected primarily along the so-called nuclear spiral, out to a projected galactocentric radius of 700 pc at a linear resolution of similar to 50 pc. We find that the velocity field of the molecular gas is in rough agreement with that of the ionized gas previously determined from optical observations. Utilizing existed CO(2-1) and CO(1-0) measurements in selected regions of the nuclear spiral, we derive characteristic intensity ratios of CO(3-2)/CO(2-1) and CO(3-2)/CO(1-0), which are both close to unity and are significantly higher than the typical intensity ratios in the disc. Such line ratios suggest high kinetic temperatures of the gas, which might be due to strong interstellar shocks prevalent in the circumnuclear region. This work is supported by National Key Research and Development Program of China (2017YFA0402703) and National Science Foundation of China (grants 11473010 and 11873028). We are grateful to Mark Goski for his strong technical support to our JCMT observations. We owe our thanks to Anne-Laure Melchior for kindly providing us with the CO(2-1) spectra, to Karl Schuster for providing us with the CO(1-0) data, and to Matthew Smith and Junhao Liu for helpful discussions.C 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society |
| Databáze: | OpenAIRE |
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