2021ApJ...909...19G

Ultra-diffuse galaxies have generated significant interest due to their large optical extents and low optical surface brightnesses, which challenge galaxy formation models. Here we present resolved synthesis observations of 12 H I-bearing ultra-diffuse galaxies (HUDs) from the Karl G. Jansky Very Large Array, as well as deep optical imaging from the WIYN 3.5 m telescope at Kitt Peak National Observatory. We present the data processing and images, including total intensity H I maps and H I velocity fields. The HUDs show ordered gas distributions and evidence of rotation, important prerequisites for the detailed kinematic models of Mancera Pina et al. We compare the H I and stellar alignment and extent, and find that H I extends beyond the already extended stellar component and the H I disk is often misaligned with respect to the stellar one, emphasizing the importance of caution when approaching inclination measurements for these extreme sources. We explore the H I mass-diameter scaling relation, and find that, although the HUDs have diffuse stellar populations, they fall along the relation with typical global H I surface densities. This resolved sample forms an important basis for more detailed study of the H I distribution in this extreme extragalactic population.