Low- and high-ionization absorption properties of MgII absorption-selectedgalaxies at intermediate redshifts. II. Taxonomy, kinematics, and galaxies

We examine a sample of 45 Mg II absorption-selected systems over the redshi ft range 0.4-1.4 in order to better understand the range of physical condit ions present in the interstellar and halo gas associated with intermediate redshift galaxies. Mg II and Fe II absorption profiles were observed at a r esolution of similar or equal to 6 km s(-1) with HIRES/Keek. Ly alpha and C IV data were measured in FOS spectra obtained from the Hubble Space Telesc ope archive (resolution similar or equal to 230 km s(-1)). We perform a mul tivariate analysis of W-r(Mg II), W-r(Fe II), W-r(C IV), and W-r(Ly alpha) (rest-frame equivalent widths) and the Mg II kinematic spread. There is a l arge range of high- to low-ionization properties and kinematics in intermed iate-redshift absorbers, that we find can be organized into five categories : "classic," "C Iv-deficient," "single/weak," "double," and "damped Ly alph a /H I-rich." These categories arise, in part, because there is a strong co nnection between low-ionization kinematics and the location of an absorber on the W-r(C IV)-W-r(Mg II) plane. Using photoionization modeling, we infer that in most absorbers a significant fraction of the C rv arises in a phas e separate from that giving rise to the Mg II. We show that many of the C I v profiles are resolved in the FOS spectra because of the velocity structur e in the C Iv gas. For 16 systems, the galaxy M-K, M-B, B-K, and impact par ameters are measured. We compare the available absorption-line properties ( taken from Paper I) to the galaxy properties but find no significant (great er than 3 sigma) correlations, although several suggestive trends are appar ent. We compare the locations of our intermediate redshift absorbers on the W-r(C rv)-W-r(Mg II) plane with those of lower and higher redshift data ta ken from the literature and find evidence for evolution that is connected w ith the Mg II kinematics seen in HIRES/Keek profiles of Mg II at z > 1.4. W e discuss the potential of using the above categorizations of absorbers to understand the evolution in the underlying physical. processes giving rise to the gas and governing its ionization phases and kinematics. We also disc uss how the observed absorbing gas evolution has interesting parallels with scenarios of galaxy evolution in which mergers and the accretion of "proto galactic clumps" govern the gas physics and provide reservoirs for elevated star formation rates at high redshift. At intermediate and lower redshifts , the galaxy gaseous components and star formation rates may become interde pendent and self-regulatory such that, at z less than or equal to 1, the ki nematics and balance of high- and low-ionization gas may be related to the presence of star-forming regions in the host galaxy.