Star formation at high redshift occurs in galaxies with high gas
fractions and high turbulent speeds. The morphology is a clumpy disk
without an exponential disk, bulge, or bar. There appear to be no exact
local analogues, but what comes close are the dwarf Irregular galaxies,
which are much lower in mass, along with very rare types called clumpy
irregular galaxies, luminous compact blue galaxies, Lyman Break
Analogs, etc.. All have a small number of giant star-forming regions,
presumably because they are all gas-rich and highly turbulent. The main
process of star formation everywhere seems to be gravitational
instabilities. The clump masses are large and the rates are large
because of the high turbulence and high gas mass fractions. There is a
relation between the star formation rate and the galaxy mass versus
redshift, called the "main sequence" line. Cosmological models have
been made that fit this line fairly well. Generally, the
SFR
versus mol
relation is similar to that in local
galaxies, with a slight preference for a rate given by the galaxy
dynamical time rather than the pure gas dynamical time. In galaxy
accretion models, the star formation rate quickly becomes equal to the
gas accretion rate. Presumably
mol
adjusts to accommodate or enforce this equilibrium.