The Dawes Review 1: Kinematic studies of star-forming galaxies across cosmic time

TL;DR

This review summarizes recent advances in high-redshift galaxy kinematic studies enabled by integral field spectroscopy, revealing that many young galaxies have regular kinematics despite irregular appearances, due to gas-rich discs.

Contribution

First comprehensive review of high-redshift galaxy kinematic surveys and models, highlighting the prevalence of regular kinematics in gas-rich young galaxies.

Findings

High-redshift galaxies often show regular kinematic structures.

Integral field spectroscopy has advanced understanding of galaxy evolution.

Gas-rich discs dominate the kinematic properties of young galaxies.

Abstract

The last seven years have seen an explosion in the number of Integral Field galaxy surveys, obtaining resolved 2D spectroscopy, especially at high-redshift. These have taken advantage of the mature capabilities of 8-10 m class telescopes and the development of associated technology such as AO. Surveys have leveraged both high spectroscopic resolution enabling internal velocity measurements and high spatial resolution from AO techniques and sites with excellent natural seeing. For the first time, we have been able to glimpse the kinematic state of matter in young, assembling star-forming galaxies and learn detailed astrophysical information about the physical processes and compare their kinematic scaling relations with those in the local Universe. Observers have measured disc galaxy rotation, merger signatures, and turbulence-enhanced velocity dispersions of gas-rich discs. Theorists have interpreted kinematic signatures of galaxies in a variety of ways (rotation, merging, outflows, and feedback) and attempted to discuss evolution vs. theoretical models and relate it to the evolution in galaxy morphology. A key point that has emerged from this activity is that substantial fractions of high-redshift galaxies have regular kinematic morphologies despite irregular photometric morphologies and this is likely due to the presence of a large number of highly gas-rich discs. There has not yet been a review of this burgeoning topic. In this first Dawes review, I will discuss the extensive kinematic surveys that have been done and the physical models that have arisen for young galaxies at high-redshift.