A CO isotopologue Line Atlas within the Whirlpool galaxy Survey (CLAWS)
We present the CO isotopologue Line Atlas within the Whirpool galaxy Survey (CLAWS), which is based on an IRAM 30 m large programme that provides a benchmark study of numerous faint CO isotopologues in the millimetre-wavelength regime across the full disc of the nearby grand-design spiral galaxy M 5...
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
23 June 2022
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| In: |
Astronomy and astrophysics
Year: 2022, Volume: 662, Pages: 1-29 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/202142247 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1051/0004-6361/202142247 Verlag, lizenzpflichtig, Volltext: https://www.aanda.org/articles/aa/abs/2022/06/aa42247-21/aa42247-21.html 
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| Author Notes: | Jakob S. den Brok, Frank Bigiel, Kazimierz Sliwa, Toshiki Saito, Antonio Usero, Eva Schinnerer, Adam K. Leroy, María J. Jiménez-Donaire, Erik Rosolowsky, Ashley T. Barnes, Johannes Puschnig, Jérôme Pety, Andreas Schruba, Ivana Bešlić, Yixian Cao, Cosima Eibensteiner, Simon C.O. Glover, Ralf S. Klessen, J.M. Diederik Kruijssen, Sharon E. Meidt, Lukas Neumann, Neven Tomičić, Hsi-An Pan, Miguel Querejeta, Elizabeth Watkins, Thomas G. Williams, and David Wilner |
| Summary: | We present the CO isotopologue Line Atlas within the Whirpool galaxy Survey (CLAWS), which is based on an IRAM 30 m large programme that provides a benchmark study of numerous faint CO isotopologues in the millimetre-wavelength regime across the full disc of the nearby grand-design spiral galaxy M 51 (NGC 5194). The survey’s core goal is to use the low-<i>J<i/> CO isotopologue lines to constrain CO excitation and chemistry, and therefrom the local physical conditions of the gas. In this survey paper, we describe the CLAWS observing and data reduction strategies. We map the <i>J<i/> = 1 → 0 and 2 → 1 transitions of the CO isotopologues <sup>12<sup/>CO, <sup>13<sup/>CO, C<sup>18<sup/>O, and C<sup>17<sup/>O, as well as several supplementary lines within the 1 mm and 3 mm window (CN(1-0), CS (2-1), CH<sub>3<sub/>OH(2-1), N<sub>2<sub/>H<sup>+<sup/> (1-0), and HC<sub>3<sub/>N (10-9)) at ~1 kpc resolution. A total observation time of 149 h offers unprecedented sensitivity. We use these data to explore several CO isotopologue line ratios in detail, study their radial (and azimuthal) trends, and investigate whether changes in line ratios stem from changes in interstellar medium properties such as gas temperatures, densities, or chemical abundances. For example, we find negative radial trends for the <sup>13<sup/>CO/<sup>12<sup/>CO, C<sup>18<sup/>O/<sup>12<sup/>CO, and C<sup>18<sup/>O/<sup>13<sup/>CO line ratios in their <i>J<i/> = 1 → 0 transitions. We also find variations with the local environment, such as higher <sup>12<sup/>CO (2-1)/(1-0) or <sup>13<sup/>CO/<sup>12<sup/>CO (1-0) line ratios in interarm regions compared to spiral arm regions. We propose that these aforementioned variations in CO line ratios are most likely due to a variation in the optical depth, though abundance variations due to selective nucleosynthesis on a galaxy-wide scale could also play a role. We also study the CO spectral line energy distribution (SLED) using archival JCMT <sup>12<sup/>CO (3-2) data and find a variation in the SLED shape with local environmental parameters, suggesting changes in the optical depth, gas temperatures, or densities. |
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| Item Description: | Gesehen am 11.08.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/202142247 |