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C I and CO in nearby spiral galaxies: I. Line ratio and abundance variations at ∼200 pc scales
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Published in: | Astronomy and astrophysics year:2023; elocationid:A36; pages:1-22; 672(2023) vom: Apr., Artikel-ID A36, Seite 1-22; month:04; volume:672; extent:22 |
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Authors and Corporations: | , , , , , , , , , , , , , , , , , , , , , , , , , , , |
Other Authors: | Schinnerer, Eva 1970- [Author] • Saito, Toshiki [Author] • Rosolowsky, Erik [Author] • Leroy, Adam [Author] • Usero, Antonio [Author] • Sandstrom, Karin [Author] • Klessen, Ralf S. 1968- [Author] • Glover, Simon [Author] • Ao, Yiping [Author] • Bešlić, Ivana [Author] • Bigiel, Frank [Author] • Cao, Yixian [Author] • Chastenet, Jérémy [Author] • Chevance, Mélanie [Author] • Dale, Daniel A. [Author] • Gao, Yu [Author] • Hughes, Annie [Author] • Kreckel, Kathryn [Author] • Kruijssen, Diederik [Author] • Pan, Hsi-An [Author] • Pety, Jérôme [Author] • Salak, Dragan [Author] • Santoro, Francesco [Author] • Schruba, Andreas [Author] • Sun, Jiayi [Author] • Teng, Yu-Hsuan [Author] • Williams, Thomas G. [Author] |
Type of Resource: | E-Book Component Part |
Language: | English |
published: |
April 2023
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Series: |
Astronomy and astrophysics, 672(2023) vom: Apr., Artikel-ID A36, Seite 1-22
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Source: | Verbunddaten SWB Lizenzfreie Online-Ressourcen |
ISSN: | 1432-0746 |
Summary: | We present new neutral atomic carbon [C I] (<sup>3<sup/>P<sub>1<sub/> → <sup>3<sup/>P<sub>0<sub/>) mapping observations within the inner ∼7 kpc and ∼4 kpc of the disks of NGC 3627 and NGC 4321 at a spatial resolution of 190 pc and 270 pc, respectively, using the Atacama Large Millimeter/Submillimeter Array (ALMA) Atacama Compact Array (ACA). We combine these with the CO(2−1) data from PHANGS-ALMA, and literature [C I] and CO data for two other starburst and/or active galactic nucleus (AGN) galaxies (NGC 1808, NGC 7469) with the aim of studying: (a) the spatial distributions of C I and CO emission; (b) the observed line ratio <i>R<i/><sub>C I/CO<sub/> = <i>I<i/><sub>[<sub>C I](1−0<sub/>)<sub/>/<i>I<i/><sub>CO(2−1<sub/>) as a function of various galactic properties; and (c) the abundance ratio of [C I/CO]. We find excellent spatial correspondence between C I and CO emission and nearly uniform <i>R<i/><sub>C I/CO<sub/> ∼ 0.1 across the majority of the star-forming disks of NGC 3627 and NGC 4321. However, <i>R<i/><sub>C I/CO<sub/> strongly varies from ∼0.05 at the center of NGC 4321 to > 0.2 − 0.5 in NGC 1808’s starbursting center and NGC 7469’s center with an X-ray-luminous AGN. Meanwhile, <i>R<i/><sub>C I/CO<sub/> does not obviously vary with ⟨<i>U<i/>⟩, which is in line with predictions from photodissociation-dominated region (PDR) models. We also find a mildly decreasing <i>R<i/><sub>C I/CO<sub/> value with an increasing metallicity over 0.7 − 0.85 <i>Z<i/><sub>⊙<sub/>, which is consistent with the literature. Assuming various typical interstellar medium (ISM) conditions representing giant molecular clouds, active star-forming regions, and strong starbursting environments, we calculated the (non)local-thermodynamic-equilibrium radiative transfer and estimated the [C I/CO] abundance ratio to be ∼0.1 across the disks of NGC 3627 and NGC 4321, similar to previous large-scale findings in Galactic studies. However, this abundance ratio likely experiences a substantial increase, up to ∼1 and ≳1 − 5 in NGC 1808’s starburst and NGC 7469’s strong AGN environments, respectively. This result is in line with the expectations for cosmic-ray dominated region (CRDR) and X-ray dominated region (XDR) chemistry. Finally, we do not find robust evidence for a generally CO-dark-and-C I-bright gas in the disk areas we probed. |
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Item Description: |
Online veröffentlicht: 27. März 2023 Gesehen am 08.08.2023 |
Physical Description: | 22 |
ISSN: | 1432-0746 |
DOI: | 10.1051/0004-6361/202244564 |