Central molecular zones in galaxies: 13CO(6-5) and molecular gas conditions in bright nearby galaxies

Fuente: arXiv
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Main Authors: Israel, F. P., Gusten, R., Lundgren, A.
Format: Preprint
Published: 2024
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author Israel, F. P.
Gusten, R.
Lundgren, A.
author_facet Israel, F. P.
Gusten, R.
Lundgren, A.
contents We summarize all available 13CO and accompanying 12CO measurements of local galaxy centers in transitions of J=5-4 and higher, including new APEX 13CO(6-5) and 12CO(6-5) observations of 11 galaxies. The observed integrated temperature ratios of 12CO(6-5) to 12CO(1-0) range from 0.10 to 0.45. Multi-aperture data indicate that 13CO(6-5) is more centrally concentrated than 12CO(6-5). The emission of 12CO(6-5) and HCO+ but not HCN may be correlated. The new data are essential to constrain the physical properties of the galaxy center molecular gas even in a simple two-phase model approximating the more complex multi-phase structure. In all galaxies, except the Seyfert AGN galaxy NGC 1068, high J emission from the center is dominated by a dense (n = 100 000) and relatively cool (T = 20 to 60 K) high-pressure gas. In contrast, the low-J lines are dominated in most galaxies by low-pressure gas of a moderate density (n = 1000) and more elevated temperature (T = 60 to 150 K). The three exceptions with significant high-pressure gas contributions to the low J emission are all associated with active central star formation.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02987
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Central molecular zones in galaxies: 13CO(6-5) and molecular gas conditions in bright nearby galaxies
Israel, F. P.
Gusten, R.
Lundgren, A.
Astrophysics of Galaxies
We summarize all available 13CO and accompanying 12CO measurements of local galaxy centers in transitions of J=5-4 and higher, including new APEX 13CO(6-5) and 12CO(6-5) observations of 11 galaxies. The observed integrated temperature ratios of 12CO(6-5) to 12CO(1-0) range from 0.10 to 0.45. Multi-aperture data indicate that 13CO(6-5) is more centrally concentrated than 12CO(6-5). The emission of 12CO(6-5) and HCO+ but not HCN may be correlated. The new data are essential to constrain the physical properties of the galaxy center molecular gas even in a simple two-phase model approximating the more complex multi-phase structure. In all galaxies, except the Seyfert AGN galaxy NGC 1068, high J emission from the center is dominated by a dense (n = 100 000) and relatively cool (T = 20 to 60 K) high-pressure gas. In contrast, the low-J lines are dominated in most galaxies by low-pressure gas of a moderate density (n = 1000) and more elevated temperature (T = 60 to 150 K). The three exceptions with significant high-pressure gas contributions to the low J emission are all associated with active central star formation.
title Central molecular zones in galaxies: 13CO(6-5) and molecular gas conditions in bright nearby galaxies
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2409.02987