Evolution of damped Lyman-alpha galaxies from hierarchical structure formation models

We investigate the evolution of damped Lyα absorption systems (dla) from hierarchical structure formation models by exploring the basic properties of DLA host-galaxies (dla galaxies) to clarify the connection between DLAs and galaxies. We find that DLA galaxies primarily consist of low surface brightness dwarf galaxies. For example, at redshift z ≤ 1, DLA galaxies have typical radius 3 kpc, surface brightness 22-27 mag arc-sec^-2, and star formation rate 10^-2 M_⊙/yr. We discuss selection effects in the detection in emission caused by compactness and brightness. Finally, we explore the radio properties at z=0 by comparing the observational results from blind radio surveys.