Growth and Destruction of Disks: Combined HI and HII View

TL;DR

This paper discusses how combined HI and HII observations can elucidate the evolution, transformation, and dynamics of large disk galaxies over time and environment, with a focus on upcoming surveys and instrumentation.

Contribution

It introduces a framework for using combined HI and optical data, including IFU instruments, to study disk galaxy evolution at z<0.5, linking halo properties with star formation and gas reservoirs.

Findings

Combined HI and optical data can trace disk evolution and star formation.

Upcoming IFU instruments will enable detailed kinematic and stellar population studies.

Future surveys will improve understanding of galaxy transformation in different environments.

Abstract

How large disk galaxies have evolved in, and out of, the blue cloud of actively star-forming galaxies as a function of environment and time is an outstanding question. Some of the largest disks become systems like M31, M33 and the Milky Way today. In denser environments, it appears they transform onto the red sequence. Tracking disk systems since z<0.5 as a function HI mass, dynamical mass, and environment should be possible in the coming decade. HI and optical data combined can sample outer and inner disk dynamics to connect halo properties with regions of most intense star-formation, and the gas reservoir to the consumption rate. We describe existing and future IFUs on 4-10m telescopes that complement upcoming HI surveys for studying disks at z<0.5. Multiple units, deployable over large fields-of-view, and with logarithmic sampling will yield kinematic and star-formation maps and properties of the stellar populations, resolving the core but retaining sensitivity to disk outskirts.