Star Formation during Galaxy Formation

TL;DR

This paper discusses how star formation in young, turbulent galaxies occurs through gravitational instabilities, with rates comparable to gas accretion, and examines how local star formation laws apply at high redshift.

Contribution

It provides insights into star formation processes in early galaxies and compares empirical laws across different cosmic epochs.

Findings

Star formation in young galaxies is driven by gravitational instabilities.

Star formation rates match gas accretion rates in these galaxies.

Empirical star formation laws hold at redshift ~2, with some variations.

Abstract

Young galaxies are clumpy, gas-rich, and highly turbulent. Star formation appears to occur by gravitational instabilities in galactic disks. The high dispersion makes the clumps massive and the disks thick. The star formation rate should be comparable to the gas accretion rate of the whole galaxy, because star formation is usually rapid and the gas would be depleted quickly otherwise. The empirical laws for star formation found locally hold at redshifts around 2, although the molecular gas consumption time appears to be smaller, and mergers appear to form stars with a slightly higher efficiency than the majority of disk galaxies.