TY - JOUR
T1 - The [CII] emission as a molecular gas mass tracer in galaxies at low and high redshifts
AU - Zanella, A.
AU - Daddi, E.
AU - Magdis, G.
AU - Santos, T. Diaz
AU - Cormier, D.
AU - Liu, D.
AU - Cibinel, A.
AU - Gobat, R.
AU - Dickinson, M.
AU - Sargent, M.
AU - Popping, G.
AU - C. Madden, S.
AU - Bethermin, M.
AU - Hughes, T. M.
AU - Valentino, F.
AU - Rujopakarn, W.
AU - Pannella, M.
AU - Bournaud, F.
AU - Walter, F.
AU - Wang, T.
AU - Elbaz, D.
AU - Coogan, R. T.
N1 - Funding Information:
W.R. is supported by JSPS KAKENHI Grant Number JP15K17604 and the Thailand Research Fund/Office of the Higher Education Commission Grant Number MRG6080294. D. L. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 694343). This paper makes use of the following ALMA data: ADS/JAO.ALMA#2012.1.00775.S ALMA is a partnership of European Southern Observatory (ESO, representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ.
Funding Information:
We are grateful to the anonymous referee for their insightful comments. A.Z. thanks C. Cicone, G. Accurso, A. Saintonge, Q. Tan, M. Aravena, A. Pope, A. Ferrara, S. Gallerani, and A. Pallottini for useful discussions. T.M.H. acknowledges support from the Chinese Academy of Sciences (CAS) and the National Commission for Scientific and Technological Research of Chile (CONICYT) through a CAS-CONICYT Joint Postdoctoral Fellowship administered by the CAS South America Center for Astronomy (CASSACA) in Santiago, Chile. D.C. is supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 702622. M.T.S was supported by a Royal Society Leverhulme Trust Senior Research Fellowship (LT150041).
Publisher Copyright:
© 2018 The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - We present ALMA Band 9 observations of the [CII]158 μm emission for a sample of 10 mainsequence galaxies at redshift z ~ 2, with typical stellar masses (logM*/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 [CII] 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 (L[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 [CII] 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 [CII] luminosity correlates with galaxies' molecular gas mass, with a mean absolute deviation of 0.2 dex and without evident systematics: the [CII]- 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.
AB - We present ALMA Band 9 observations of the [CII]158 μm emission for a sample of 10 mainsequence galaxies at redshift z ~ 2, with typical stellar masses (logM*/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 [CII] 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 (L[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 [CII] 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 [CII] luminosity correlates with galaxies' molecular gas mass, with a mean absolute deviation of 0.2 dex and without evident systematics: the [CII]- 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.
KW - Galaxies: ISM-galaxies: star formation
KW - Galaxies: evolution
KW - Galaxies: high redshift
KW - Galaxies: starburst
KW - Submillimetre: galaxies
UR - http://www.scopus.com/inward/record.url?scp=85058453548&partnerID=8YFLogxK
U2 - 10.1093/MNRAS/STY2394
DO - 10.1093/MNRAS/STY2394
M3 - Article
AN - SCOPUS:85058453548
VL - 481
SP - 1976
EP - 1999
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -