paper

VLA Legacy Survey of Molecular Gas in Massive Star-forming Galaxies at High Redshift

arXiv:2302.03713 · doi:10.3847/1538-4357/acb931

Abstract

We present initial results of an ongoing survey with the Karl G. Jansky Very Large Array targeting the CO( = 1-0) transition in a sample of 30 submillimeter-selected, dusty star-forming galaxies at 2-5 with existing mid-- CO detections from ALMA and NOEMA, of which 17 have been fully observed. We detect CO(1-0) emission in 11 targets, along with three tentative (1.5-2) detections; three galaxies are undetected. Our results yield total molecular gas masses of 6-2310 (/1) M, with gas mass fractions, =/(+), of 0.1-0.8 and a median depletion time of (14070) Myr. We find median CO excitation ratios of = 0.750.39 and = 0.630.44, with a significant scatter. We find no significant correlation between the excitation ratio and a number of key parameters such as redshift, CO(1-0) line width or . We only find a tentative positive correlation between and the star-forming efficiency, but we are limited by our small sample size. Finally, we compare our results to predictions from the SHARK semi-analytical model, finding a good agreement between the molecular gas masses, depletion times and gas fractions of our sources and their SHARK counterparts. Our results highlight the heterogeneous nature of the most massive star-forming galaxies at high-redshift, and the importance of CO(1--0) observations to robustly constrain their total molecular gas content and ISM properties.

arXiv comment10 pages, 15 figures. Accepted for publication in ApJ

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