paper

Ionized Carbon in Galaxies: The [C II] 158 m Line as a Total Molecular Gas Mass Tracer Revisited

arXiv:2410.20684 · doi:10.3847/1538-4357/ad8c3e

Abstract

In this paper we present a statistical study of the [C II] 158 m line and the CO(1-0) emission for a sample of 200 local and high- (32 sources with ) galaxies with much different physical conditions. We explore the correlation between the luminosities of [C II] and CO(1-0) lines, and obtain a strong linear relationship, confirming that [C II] is able to trace total molecular gas mass, with a small difference between (U)LIRGs and less-luminous galaxies. The tight and linear relation between [C II] and CO(1-0) is likely determined by the average value of the observed visual extinction and the range of in galaxies. Further investigations into the dependence of on different physical properties show that (1) anti-correlates with , and the correlation becomes steeper when ; (2) correlates positively with the distance from the main sequence when ; and (3) tends to show a systematically smaller value in systems where the [C II] emission is dominated by ionized gas. Our results imply that caution needs to be taken when applying a constant [[C II]-to- conversion factor to estimate the molecular gas content in extreme cases, such as galaxies having low-level star formation activity or high SFR surface density.

Accepted for publication in ApJ; 18 pages, 2 tables and 8 figures

References in corpus (58)

Ionized Carbon in Galaxies: The [C II] 158 $μ$m Line as a Total Molecular Gas Mass Tracer Revisited · wovepaper