QUASARS PROBING QUASARS. VIII. THE PHYSICAL PROPERTIES OF THE COOL CIRCUMGALACTIC MEDIUM SURROUNDING z similar to 2-3 MASSIVE GALAXIES HOSTING QUASARS

摘要

We characterize the physical properties of the cool T similar to 10(4) K circumgalactic medium (CGM) surrounding z similar to 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 spectra of high dispersion and high signal-to-noise ratio, we find extreme kinematics with low metal ion lines typically spanning approximate to 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]approximate to-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. x. 10(11)M(circle dot) (R-perpendicular to/160 kpc)(2), accounting for approximate to 1/3 of the baryonic budget of the galaxy halo. 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 Lya 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 sub-parsec-scale gas clumps.