An ALMA/NOEMA survey of the molecular gas properties of high-redshift star-forming galaxies
Artikel i vetenskaplig tidskrift, 2021

We have used ALMA and NOEMA to study the molecular gas reservoirs in 61 ALMA-identified submillimetre galaxies (SMGs) in the COSMOS, UDS, and ECDFS fields. We detect 12CO (Jup = 2-5) emission lines in 50 sources, and [C I](3P1 -3P0) emission in eight, at z = 1.2-4.8 and with a median redshift of 2.9±0.2. By supplementing our data with literature sources, we construct a statistical CO spectral line energy distribution and find that the 12CO line luminosities in SMGs peak at Jup ∼ 6, consistent with similar studies. We also test the correlations of the CO, [C I], and dust as tracers of the gas mass, finding the three to correlate well, although the CO and dust mass as estimated from the 3-mm continuum are preferable. We estimate that SMGs lie mostly on or just above the star-forming main sequence, with a median gas depletion timescale, tdep = Mgas/SFR, of 210±40 Myr for our sample. Additionally, tdep declines with redshift across z ∼ 1-5, while the molecular gas fraction, μgas = Mgas/M*, increases across the same redshift range. Finally, we demonstrate that the distribution of total baryonic mass and dynamical line width, Mbaryon-σ, for our SMGs is consistent with that followed by early-type galaxies in the Coma cluster, providing strong support to the suggestion that SMGs are progenitors of massive local spheroidal galaxies. On the basis of this, we suggest that the SMG populations above and below an 870-μm flux limit of S870 ∼ 5mJy may correspond to the division between slow and fast rotators seen in local early-type galaxies.

galaxies: Star formation

submillimetre: Galaxies

galaxies: Evolution


Jack E. Birkin

Durham University

Axel Weiss


J. L. Wardlow

Lancaster University

Ian Smail

Durham University

A. M. Swinbank

Durham University

U. Dudzeviciute

Durham University

Fang Xia An

University of the Western Cape

Y. Ao

University of Science and Technology of China

Chinese Academy of Sciences

S. C. Chapman

Dalhousie University

Chian Chou Chen

Academia Sinica

E. da Cunha

University of Western Australia

H. Dannerbauer

Instituto de Astrofísica de Canarias

Universidad de la Laguna

Bitten Gullberg

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

J. A. Hodge

Universiteit Leiden

S. Ikarashi

Durham University

R. J. Ivison

European Southern Observatory (ESO)

Y. Matsuda

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

S. M. Stach

Durham University

F. Walter


W. H. Wang

Academia Sinica

P. van der Werf

Universiteit Leiden

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 501 3 3926-3950


Subatomär fysik

Astronomi, astrofysik och kosmologi

Sannolikhetsteori och statistik



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