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Resolved CO(1–0) Emission and Gas Properties in Luminous Dusty Star-forming Galaxies at z = 2–4

Stanley, F.; Jones, B. M.; Riechers, D. A.; Yang, C.; Berta, S.; Cox, P.; Bakx, T. J. L. C.; Cooray, A.; Dannerbauer, H.; Dye, S.; Hughes, D. H.; Ivison, R. J.; Jin, S.; Lehnert, M.; Neri, R.; Omont, A.; van der Werf, P.; Weiss, A.


F. Stanley

B. M. Jones

D. A. Riechers

C. Yang

S. Berta

P. Cox

T. J. L. C. Bakx

A. Cooray

H. Dannerbauer

Associate Professor

D. H. Hughes

R. J. Ivison

S. Jin

M. Lehnert

R. Neri

A. Omont

P. van der Werf

A. Weiss


We present the results of a survey of CO(1−0) emission in 14 infrared luminous dusty star-forming galaxies (DSFGs) at 2 < z < 4 with the NSF's Karl G. Jansky Very Large Array. All sources are detected in 12CO(1−0), with an angular resolution of ∼1''. Seven sources show extended and complex structure. We measure CO luminosities of $(\mu ){L}_{\mathrm{CO}(1-0)}^{{\prime} }=0.4\mbox{--}2.9\times {10}^{11}$ K km s−1 pc2, and molecular gas masses of $(\mu ){M}_{{{\rm{H}}}_{2}}\,=1.3\mbox{--}8.6\times {10}^{11}$ M⊙, where (μ) is the magnification factor. The derived molecular gas depletion times of tdep = 40–460 Myr, cover the expected range of both normal star-forming galaxies and starbursts. Compared to the higher −J CO transitions previously observed for the same sources, we find CO temperature brightness ratios of r32/10 = 0.4–1.4, r43/10 = 0.4–1.7, and r54/10 = 0.3–1.3. We find a wide range of CO spectral line energy distributions (SLEDs), in agreement with other high-z DSFGs, with the exception of three sources that are most comparable to Cloverleaf and APM08279+5255. Based on radiative transfer modeling of the CO SLEDs we determine densities of ${n}_{{{\rm{H}}}_{2}}=0.3-8.5\times {10}^{3}$ cm−3 and temperatures of TK = 100–200 K. Lastly, four sources are detected in the continuum, three have radio emission consistent with their infrared-derived star formation rates, while HerBS-70E requires an additional synchrotron radiation component from an active galactic nucleus. Overall, we find that even though the sample is similarly luminous in the infrared, by tracing the CO(1−0) emission a diversity of galaxy and excitation properties are revealed, demonstrating the importance of CO(1−0) observations in combination to higher-J transitions.


Stanley, F., Jones, B. M., Riechers, D. A., Yang, C., Berta, S., Cox, P., …Weiss, A. (2023). Resolved CO(1–0) Emission and Gas Properties in Luminous Dusty Star-forming Galaxies at z = 2–4. Astrophysical Journal, 945(1), Article 24.

Journal Article Type Article
Acceptance Date Jan 27, 2023
Online Publication Date Mar 2, 2023
Publication Date Mar 1, 2023
Deposit Date Mar 4, 2023
Publicly Available Date Mar 6, 2023
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 945
Issue 1
Article Number 24
Keywords High-redshift galaxies; Galaxies; Starburst galaxies; CO line emission
Public URL
Publisher URL


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