The [C ii] emission as a molecular gas mass tracer in galaxies at low and high redshifts - Archive ouverte HAL
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2018

The [C ii] emission as a molecular gas mass tracer in galaxies at low and high redshifts

A. Zanella
  • Fonction : Auteur
Emanuele Daddi
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T. Diaz Santos
  • Fonction : Auteur
D. Liu
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A. Cibinel
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M. Dickinson
G. Popping
  • Fonction : Auteur
M. Béthermin
W. Rujopakarn
M. Pannella
F. Walter
R. T. Coogan
  • Fonction : Auteur

Résumé

We present ALMA Band 9 observations of the [C II]158 μm emission for a sample of 10 main-sequence galaxies at redshift z ˜ 2, with typical stellar masses (log M⋆/M⊙ ˜ 10.0-10.9) and star formation rates (˜35-115 M⊙ yr-1). Given the strong and well-understood evolution of the interstellar medium from the present to z = 2, we investigate the behaviour of the [C II] emission and empirically identify its primary driver. We detect [C II] from six galaxies (four secure and two tentative) and estimate ensemble averages including non-detections. The [C II]-to-infrared luminosity ratio ([C II]/LIR) of our sample is similar to that of local main-sequence galaxies (˜2 × 10-3), and ˜10 times higher than that of starbursts. The [C II] emission has an average spatial extent of 4-7 kpc, consistent with the optical size. Complementing our sample with literature data, we find that the [C II] luminosity correlates with galaxies' molecular gas mass, with a mean absolute deviation of 0.2 dex and without evident systematics: the [C II]-to-H2 conversion factor (α _[C II] ˜ 30 M⊙/L⊙) is largely independent of galaxies' depletion time, metallicity, and redshift. [C II] seems therefore a convenient tracer to estimate galaxies' molecular gas content regardless of their starburst or main-sequence nature, and extending to metal-poor galaxies at low and high redshifts. The dearth of [C II] emission reported for z > 6-7 galaxies might suggest either a high star formation efficiency or a small fraction of ultraviolet light from star formation reprocessed by dust.
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Dates et versions

hal-02043132 , version 1 (06-09-2024)

Identifiants

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A. Zanella, Emanuele Daddi, G. Magdis, T. Diaz Santos, D. Cormier, et al.. The [C ii] emission as a molecular gas mass tracer in galaxies at low and high redshifts. Monthly Notices of the Royal Astronomical Society, 2018, 481 (2), pp.1976-1999. ⟨10.1093/mnras/sty2394⟩. ⟨hal-02043132⟩
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