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

Autor: Castillo, Marta Frias, Hodge, Jacqueline, Rybak, Matus, van der Werf, Paul, Smail, Ian, Birkin, Jack, Chen, Chian-Chou, Chapman, Scott, Hill, Ryley, Lagos, Claudia del P., Liao, Cheng-Lin, da Cunha, Elisabete, Rivera, Gabriela Calistro, Chen, Jianhang, Andrade, Eric Jimenez, Murphy, Eric, Scott, Douglas, Swinbank, Mark, Walter, Fabian, Ivison, Rob, Dannerbauer, Helmut
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
DOI: 10.3847/1538-4357/acb931
Popis: We present initial results of an ongoing survey with the Karl G. Jansky Very Large Array targeting the CO($J$ = 1-0) transition in a sample of 30 submillimeter-selected, dusty star-forming galaxies at $z =$ 2-5 with existing mid--$J$ 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 ($\sim$1.5-2$\sigma$) detections; three galaxies are undetected. Our results yield total molecular gas masses of 6-23$\times$10$^{10}$ ($\alpha_\mathrm{CO}$/1) M$_\odot$, with gas mass fractions, $f_\mathrm{gas}$=$M_\mathrm{mol}$/($M_*$+$M_\mathrm{mol}$), of 0.1-0.8 and a median depletion time of (140$\pm$70) Myr. We find median CO excitation ratios of $r_{31}$ = 0.75$\pm$0.39 and $r_{41}$ = 0.63$\pm$0.44, 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 $\Sigma_\mathrm{SFR}$. We only find a tentative positive correlation between $r_{41}$ 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.
Comment: 10 pages, 15 figures. Accepted for publication in ApJ
Databáze: arXiv
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