Precious Metals (or Lack of) in SDSS Quasar Spectra
Cathy Cooksey



Spectroscopic surveys of quasars yield a random sample of intervening absorbing gas clouds that can be used to constrain the on-going and summative enrichment processes in the universe. The CIV and MgII doublets have proven to be important tracers of the circum-galactic medium and its evolution from z = 6 to 0. We vastly improved the 1.5 < z < 4.5 absorber measurements by identifying over 15,000 CIV systems from a survey of thousands of SDSS DR7 QSOs. MgII absorption systems have been well-studied at 0.4 < z < 2.3, in SDSS quasar spectra, since the early data-release, and we surveyed the SDSS DR7 quasar catalog for MgII absorbers, as part of our on-going effort to compile fairly comparable samples of metal lines. I will summarize the SDSS CIV and MgII absorbers, relate them to galaxies and galaxy evolution, and discuss what's next, including our on-going search for metal-poor Lyman-limit systems that may trace inflowing gas (the fuel for future star formation).