Observations:

The pilot program (VLA/20A-083) was accomplished in 2023 (Stanley et al. 2023) with CO(1-0) observations of 14 DSFGs using VLA C-configuration. Following its success, a full-fledged Vz-GAL program took a shape in 2023. From the full z-GAL sample of 135 galaxies with robust spectroscopic redshifts, 83 were planned to be observed in the 2023B semester (Oct 2023 to Jan 2024; VLA/23B-169). These 83 galaxies primarily lie in the right ascension (RA) 23hr to 9hr fields, which can be observed most efficiently at the best observing hours of the day in this semester. All the Vz-GAL observations aim to utilize the most compact D-configuration of the VLA, which is the best for measuring integrated gas masses of the targeted galaxies. Moreover, it offers the best phase stability for these demanding high-frequency observations. Four different VLA receivers were employed to cover a wide range in redshift to detect CO(1-0).

Based on the successful analysis of the data from the 2023B semester, the rest of the sources from the RA 12hr to 15hr fields were accepted to be followed up in 2025A semester (Feb 2025 to May 2025; VLA/25A-099). However, only 26 additional sources could be observed in this spring-summer semester. The combined data analysis from 2023B and 2025A is currently under preparation (Prajapati et al. 2025; ApJS; in prep.). The figure below shows a summary of the target fields and various receivers used for the Vz-GAL observations, where Phase I and Phase II correspond to the original observation plans for 2023B and 2025A semesters, respectively.