The Early Universe Molecular Emission Line Galaxies ( EMGs ) are a population of galaxies with only 36 examples that hold great promise for the study of galaxy formation and evolution at high redshift .
The classification , luminosity of molecular line emission , molecular mass , far-infrared ( FIR ) luminosity , star formation efficiency , morphology , and dynamical mass of the currently known sample are presented and discussed .
The star formation rates derived from the FIR luminosity range from about 300 to 5000 M _ { \odot } year ^ { -1 } and the molecular mass from 4 \times 10 ^ { 9 } to 1 \times 10 ^ { 11 } M _ { \odot } .
At the lower end , these star formation rates , gas masses , and diameters are similar to those of local ultraluminous infrared galaxies , and represent starbursts in centrally concentrated disks , sometimes , but not always , associated with active galactic nuclei .
The evidence for large ( > 5 kpc ) molecular disks is limited .
Morphology and several high angular resolution images suggest that some EMGs are mergers with a massive molecular interstellar medium in both components .
A critical question is whether the EMGs , in particular those at the higher end of the gas mass and luminosity distribution , represent the formation of massive , giant elliptical galaxies in the early Universe .
The sample size is expected to grow explosively in the era of the Atacama Large Millimeter Array ( ALMA ) .