Faint Ly alpha Emitters, Star-forming Galaxies, and Damped Ly alpha Systems

We have discovered a population of faint single line emitters, likely to be identified with faint z similar to 3 Ly alpha emitters and with the host galaxies of damped Lyman alpha systems. The objects appear to constitute the bulk of the star-forming galaxies detected so far from the ground, and are likely to provide the gaseous reservoir from which present-day Milky way type galaxies have formed. Unlike color-selected (yman break galaxies, these objects appear to have low star-formation rates, relatively strong Lyalpha emission, and low masses, metallicities, and dust content (s.a. arXiv:0711.1354).