Pathways through interstellar matter: - From the closest stars to the most distant quasars

Abstract

Observations of quasar absorption systems relevant for studies of star formation at redshift 2 </= z </= 4 are briefly reviewed. Emphasis is given on the role played by dust in our understanding of the star formation history of galaxies detected as absorption systems. Local interstellar studies are used as a reference for understanding the properties of high redshift interstellar media. An example is shown of the potential effects of dust extinction on the metallicity-N(HI) distribution obtained from magnitude-limited surveys of damped lyman alpha absorbers.