Neutral Carbon Emission in Luminous Infrared Galaxies: The [C i] Lines as Total Molecular Gas Tracers

• Published in: Astrophysical journal. Letters Vol. 840; no. 2; p. L18
• Main Authors: Jiao, Qian, Zhao 赵, Yinghe 应和, Zhu, Ming, Lu, Nanyao, Gao 高, Yu 煜, Zhang, Zhi-Yu
• Format: Journal Article
• Language: English
• Published: Austin IOP Publishing 10.05.2017
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Atomic properties; ATOMS; CARBON; CARBON MONOXIDE; Conversion; Correlation; EMISSION; EXCITATION; FAR INFRARED RADIATION; GALAXIES; HYDROGEN; Infrared astronomy; LUMINOSITY; MASS; Molecular gases; MOLECULES; Tracers
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/aa6f0f

Abstract We present a statistical study of the [C i ] ( 3 P 1 3 P 0 ), [C i ] ( 3 P 2 3 P 1 ) lines (hereafter [C i ] (1–0) and [C i ] (2–1), respectively) and the CO(1–0) line for a sample of (ultra-)luminous infrared galaxies ((U)LIRGs). We explore the correlations between the luminosities of CO(1–0) and [C i ] lines, and find that correlates almost linearly with both and , suggesting that [C i ] lines can trace total molecular gas mass, at least for (U)LIRGs. We also investigate the dependence of / , / , and / on the far-infrared color of 60-to-100 μ m, and find non-correlation, a weak correlation, and a modest correlation, respectively. Under the assumption that these two carbon transitions are optically thin, we further calculate the [C i ] line excitation temperatures, atomic carbon masses, and mean [C i ] line flux-to-H 2 mass conversion factors for our sample. The resulting masses using these [C i ]-based conversion factors roughly agree with those derived from and CO-to-H 2 conversion factor.