The ALMA View of High-Redshift Galaxy Formation
Renske Smit, Rebecca A.A. Bowler
The advent of routine operations with the Atacama Large Millimeter/submillimeter Array (ALMA) in the past decade has led to a revolution in the direct study of the interstellar medium (ISM) in “normal” high-redshift galaxies in the rest-frame far-infrared (FIR). This review summarizes the observational literature on
z
> 6.5 sources observed with ALMA and NOEMA (NOrthern Extended Millimeter Array). The main findings are as follows:
Cool gas consistently scales with star formation in a wide range of galaxy environments, similar to local relations, suggesting that fundamental processes of star formation have stayed relatively constant over 13 billion years of cosmic time. Significant metal enrichment is present in galaxies just ∼300–400 million years after the Big Bang.
There is a trend to a higher obscured fraction of star formation with stellar mass and star-formation rate (SFR) already in place at
z
The estimated dust masses compared to the stellar mass suggest that rapid dust enrichment occurs, likely from supernovae with little dust destruction and/or rapid growth in the ISM, which is in agreement maximal predictions from models. In individual sources, cold disks are already in existence, with their gas disks being more extended and smoother than their observed stellar counterparts.