This is a two.year collaborative project between Jill Bechtold of the University of Arizona and Huang Keliang of Nanjing University to study physical conditions in the early universe. The project is sponsored by NSF and the Chinese State Education Commission. The absorption lines observed in the spectra of very distant quasars provide a powerful probe of intervening gas along the line of sight. The high luminosities of quasars enable astronomers to study the Universe at great distances and hence at epochs when the Universe was about 20 percent of its current age. This was a period when many important events took place .. the formation and rapid early evolution of galaxies, the beginnings of the collapse of large structures such as clusters of galaxies and superclusters, and the rapid turn.on of quasars themselves. Some quasar absorption lines are caused by clouds in the interstellar medium of normal galaxies; others by intergalactic clouds in the interstellar medium of normal galaxies; others by intergalactic clouds that probably represent pre.galactic or proto.galactic material of primordial metal abundance. In either case, quasar absorption lines provide direct information about the physical conditions in objects in the early Universe that are too faint to study any other way. This goal of this project is to analyze the most detailed optical spectra of quasar absorption lines obtainable with currently available telescopes and instrumentation. The spectra were obtained with the echelle spectro g.raph at the 4 meter telescope at the Kitt Peak National Observatory.
