The HASHTAG project I. A survey of CO(3–2) emission from the star forming disc of M31
| Autor: | Francisca Kemper, Chien-Hsiu Lee, Sarah Ragan, Peter Scicluna, Harriet Parsons, Thomas M. Hughes, Xue-Jian Jiang, Xindi Tang, Jinhua He, Bumhyun Lee, Sébastien Viaene, Michał J. Michałowski, Neven Tomičić, Matthew Smith, Ming Zhu, Martin Bureau, Zhiyuan Li, Thomas G. Williams, Stephen Anthony Eales, Yiping Ao, Richard de Grijs, Timothy A. Davis, Christine D. Wilson, Yu Gao, Zongnan Li, David Eden, Aeree Chung, Isabella Lamperti, Yong Shi |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Physics
Andromeda Galaxy 010308 nuclear & particles physics Star formation FOS: Physical sciences Astronomy and Astrophysics Radial distribution Astrophysics Radius Star (graph theory) Intensity ratio 01 natural sciences Astrophysics - Astrophysics of Galaxies 13. Climate action Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences 010303 astronomy & astrophysics Line (formation) |
| ISSN: | 0035-8711 |
| Popis: | We present a CO(3-2) survey of selected regions in the M31 disc as part of the JCMT large programme, HARP and SCUBA-2 High-Resolution Terahertz Andromeda Galaxy Survey (HASHTAG). The 12 CO(3-2) fields in this survey cover a total area of 60 square arcminutes, spanning a deprojected radial range of 2 - 14 kpc across the M31 disc. Combining these observations with existing IRAM 30m CO(1-0) observations and JCMT CO(3-2) maps of the nuclear region of M31, as well as dust temperature and star formation rate surface density maps, we are able to explore the radial distribution of the CO(3-2)/CO(1-0) integrated intensity ratio (R31) and its relationship with dust temperature and star formation. We find that the value of R31 between 2 - 9 kpc galactocentric radius is 0.14, significantly lower than what is seen in the nuclear ring at ~1 kpc (R31 ~ 0.8), only to rise again to 0.27 for the fields centred on the 10 kpc star forming ring. We also found that R31 is positively correlated with dust temperature, with Spearman's rank correlation coefficient $\rho$ = 0.55. The correlation between star formation rate surface density and CO(3--2) intensity is much stronger than with CO(1-0), with $\rho$ = 0.54 compared to -0.05, suggesting that the CO(3-2) line traces warmer and denser star forming gas better. We also find that R31 correlates well with star formation rate surface density, with $\rho$ = 0.69. Comment: 21 pages, 10 figures, accepted by MNRAS for publication |
| Databáze: | OpenAIRE |
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