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 , RAPHAEL ALEXANDRE SIMON
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.
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: evolution
KW - Galaxies: high redshift
KW - Galaxies: ISM-galaxies: star formation
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 -