First results from a study of high ionization absorption properties in \sim 30 Mg ii absorption selected galaxies are presented .
We have tested for correlations of Mg ii , C iv , Si iv , N v , and O vi equivalent widths with the galaxy properties and Mg ii gas kinematics .
The results are suggestive of multi–phase halos with little to no global ionization gradient with impact parameter .
C iv may arise in both the Mg ii –Ly \alpha clouds and a high ionization “ halo ” traced by O vi .
We also report on an unbiased survey for weak Mg ii systems using HIRES/Keck spectra .
At \left < z \right > = 0.9 , we find dN / dz = 1.6 \pm 0.1 for 0.02 < W ( \lambda 2796 ) < 0.3 Å and that weak systems comprise \sim 65 % of all Mg ii absorbers .
In all but one case , the weak Mg ii systems exhibit Fe ii absorption with \left < \log N ( \hbox { Fe~ { } { \sc ii } } ) / N ( \hbox { Mg~ { } { \sc ii } } ) \right > = -0.3 \pm 0.4 measured for the sample .
We suggest that weak Mg ii absorbers comprise a substantial yet–to–be explored population .
If weak systems select the LSB and/or dwarf galaxy population , then the weakest Mg ii absorbers may provide one of the most sensitive tracers of chemical enrichment and evolution of the UV background from z = 2 to z = 0 .