Prachi Prajapati

Reconstructing the physical mechanisms that have shaped present-day galaxies remains a primary goal in observational cosmology. I will introduce the VLA Vz-GAL CO(1-0) cold molecular gas large survey, a comprehensive endeavor targeting 106 luminous dusty star-forming galaxies (DSFGs) across redshifts 1 to 6. Vz-GAL more than doubles the total sample size of high-redshift CO(1-0) detections, transforming the field by enabling statistically robust separation of intrinsic cosmic trends from small-number statistical biases. I will highlight results that discuss the evolution of cold molecular gas reservoirs, their depletion timescales, and star-formation efficiencies in Vz-GAL high-redshift DSFGs, compared with other local and distant galactic populations. In addition, rigorously derived CO excitation line ratios will be presented, which yield new insights into the physical state of molecular gas in the early universe. Preliminary findings regarding gas-to-dust mass ratios and [CI](1-0)/CO(1-0) luminosity ratios will further emphasize the necessity for refined radiative transfer modeling to characterize the star-forming interstellar medium via dust and CO line spectral energy distributions, and emphasize the importance of forthcoming efforts aimed at follow-up [CI] observations.