First results from the Vz-GAL VLA Large Program

These sources are selected based on having redshifts and mid-/high-J CO transitions from the NOrthern Extended Millimeter Array z-GAL survey. We successfully detect CO(J=1-0) emission in 90/92 galaxies at the expected positions and redshifts, including nine tentative detections at 2{sigma}-3{sigma} significance, and CO(J=2-1) emission in 10 of these galaxies.

The CO(J=1-0) luminosities suggest apparent gas masses in the range {mu}M_H2_=(2-20)x10^11^({alpha}_CO_/4.0)M_{sun}_, which implies gas depletion times of 50-600Myr. These timescales show similar spread as local ULIRGs, suggesting a self-regulatory mechanism that maintains a consistent star formation rate per unit gas mass in starbursts across redshifts. To quantify the contribution of "excitation correction" factors to gas mass estimates, we calculate median CO line brightness temperature ratios of r21=0.88{\pm}0.25, r31=0.61{\pm}0.22, r41=0.49{\pm}0.15, r51=0.47{\pm}0.13, and r61=0.28{\pm}0.13.