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DC Field | Value | Language |
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dc.contributor.author | Patra, Narendra Nath | - |
dc.date.accessioned | 2020-07-07T08:21:35Z | - |
dc.date.available | 2020-07-07T08:21:35Z | - |
dc.date.issued | 2020-06 | - |
dc.identifier.citation | Astronomy & Astrophysics, 2020, Vol.638, Article No. A66 | en_US |
dc.identifier.issn | 0004-6361 | - |
dc.identifier.issn | 1432-0746 (Online) | - |
dc.identifier.uri | http://hdl.handle.net/2289/7495 | - |
dc.description | Open Access | en_US |
dc.description.abstract | As recent observations of the molecular discs in spiral galaxies point to the existence of a diffuse, low-density thick molecular disc along with the prominent thin one, we investigate the observational signatures of this thick disc by theoretically modelling two-component molecular discs in a sample of eight nearby spiral galaxies. Assuming a prevailing hydrostatic equilibrium, we set up and solved the joint Poisson’s-Boltzmann equation to estimate the three-dimensional distribution of the molecular gas and the molecular scale height in our sample galaxies. The molecular scale height in a two-component molecular disc is found to vary between 50 and 300 pc, which is higher than what is found in a single-component disc. We find that this scale height can vary significantly depending on the assumed thick disc molecular gas fraction. We also find that the molecular gas flares as a function of the radius and follows a tight exponential law with a scale length of (0.48 ± 0.01)r25. We used the density solutions to produce the column density maps and spectral cubes to examine the ideal observing conditions to identify a thick molecular disc in galaxies. We find that unless the molecular disc is an edge-on system and imaged with a high spatial resolution (≲100 pc), it is extremely hard to identify a thick molecular disc in a column density map. The spectral analysis further reveals that at moderate to high inclination (i ≳ 40°), spectral broadening can fictitiously introduce the signatures of a two-component disc into the spectral cube of a single-component disc. Hence, we conclude that a low inclination molecular disc imaged with high spatial resolution would serve as the ideal site for identifying the thick molecular disc in galaxies. | en_US |
dc.language.iso | en | en_US |
dc.publisher | EDP Sciences for European Southern Observatory | en_US |
dc.relation.uri | https://ui.adsabs.harvard.edu/abs/2020A%26A...638A..66P/abstract | en_US |
dc.relation.uri | https://arxiv.org/abs/2004.13056 | en_US |
dc.relation.uri | https://doi.org/10.1051/0004-6361/201936483 | en_US |
dc.rights | 2020 European Southern Observatory | en_US |
dc.subject | molecular data | en_US |
dc.subject | ISM: molecules | en_US |
dc.subject | galaxies: kinematics and dynamics | en_US |
dc.subject | galaxies: spiral | en_US |
dc.subject | galaxies: structure | en_US |
dc.title | Theoretical modelling of two-component molecular discs in spiral galaxies | en_US |
dc.type | Article | en_US |
Appears in Collections: | Research Papers (A&A) |
Files in This Item:
File | Description | Size | Format | |
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2020_Astronomy and Astrophysics_Vol.638_Article No.A66.pdf | Open Access | 2.65 MB | Adobe PDF | View/Open |
2020_Astronomy and Astrophysics_Vol.638_Article No.A66.epub | 12.15 MB | EPUB | View/Open |
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