Driving the Gaseous Evolution of Massive Galaxies in the Early Universe

TL;DR

This paper reviews recent progress in understanding the molecular gas in high-redshift galaxies, revealing its role in star formation, galaxy mergers, and early galaxy growth, based on extensive observations and surveys.

Contribution

It provides a comprehensive overview of observational advances in molecular gas studies in early universe galaxies, highlighting new insights into galaxy evolution.

Findings

Molecular gas properties correlate with star formation rates.

Gas dynamics distinguish merger stages and disk galaxies.

Massive starburst galaxies at z>5 inform early galaxy growth.

Abstract

Studies of the molecular interstellar medium that fuels star formation and supermassive black hole growth in galaxies at cosmological distances have undergone tremendous progress over the past few years. Based on the detection of molecular gas in >120 galaxies at z=1 to 6.4, we have obtained detailed insight on how the amount and physical properties of this material in a galaxy are connected to its current star formation rate over a range of galaxy populations. Studies of the gas dynamics and morphology at high spatial resolution allow us to distinguish between gas-rich mergers in different stages along the "merger sequence" and disk galaxies. Observations of the most massive gas-rich starburst galaxies out to z>5 provide insight into the role of cosmic environment for the early growth of present-day massive spheroidal galaxies. Large-area submillimeter surveys have revealed a rare population of extremely far-infrared-luminous gas-rich high-redshift objects, which is dominated by strongly lensed, massive starburst galaxies. These discoveries have greatly improved our understanding of the role of molecular gas in the evolution of massive galaxies through cosmic time.