Models of Five Absorption‐Line Systems along the Line of Sight Toward PG 0117+213

Abstract

We present our investigation into the physical conditions of the gas in five intervening quasar absorption-line systems along the line of sight toward the quasar PG 0117+213, with redshifts of z=0.57, 0.72, 1.04, 1.32, and 1.34. Photoionization modeling of Hubble Space Telescope, Keck I, and Palomar data, using the code Cloudy, is employed to derive densities and metallicities of the multiple phases of gas required to fit the absorption profile for each system. We discuss the implications of these models for galaxy evolution, including the interpretation of ``C IV deficiency'' and damped Lyα absorbers (DLAs), and the relationships between galaxy morphology, galaxy luminosity, and absorption signature. Based in part on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among Caltech, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Based in part on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by the STScI for the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.