We characterize the physical properties of the cool T \sim 10 ^ { 4 } K circumgalactic medium surrounding z \sim 2–3 quasar host galaxies , which are predicted to evolve into present day massive ellipticals .
Using a statistical sample of 14 quasar pairs with projected separation < 300 { kpc } and high dispersion , high S/N spectra , we find extreme kinematics with low metal ion lines typically spanning \approx 500 { km s ^ { -1 } } , exceeding any previously studied galactic population .
The CGM is significantly enriched , even beyond the virial radius , with a median metallicity [ M/H ] \approx - 0.6 .
The \alpha /Fe abundance ratio is enhanced , suggesting that halo gas is primarily enriched by core-collapse supernovae .
The projected cool gas mass within the virial radius is estimated to be 1.9 \times 10 ^ { 11 } { M } _ { \odot } ( R _ { \perp } / 160 { kpc } ) ^ { 2 } , accounting for \approx 1 / 3 of the galaxy halo baryonic budget .
The ionization state of CGM gas increases with projected distance from the foreground quasars , contrary to expectation if the quasar dominates the ionizing radiation flux .
However , we also found peculiarities not exhibited in the CGM of other galaxy populations .
In one absorption system , we may be detecting unresolved fluorescent Ly \alpha emission , and another system shows strong N v lines .
Taken together these anomalies suggest that transverse sightlines are at least in some cases possibly illuminated .
We also discovered a peculiar case where detection of the C ii fine structure line implies an electron density > 100 { cm ^ { -3 } } and subparsec scale gas clumps .