2019ApJ...887...78C

Rich complexes of associated absorption lines (AALs) in quasar spectra provide unique information about gaseous infall, outflows, and feedback processes in quasar environments. We study five quasars at redshifts z ∼ 3.1-4.4 with AAL complexes containing from 7 to 18 C IV λ1548, 1551 systems in high-resolution spectra. These complexes span velocity ranges <=3600 km s^–1 within <=8200 km s^–1 of the quasar redshifts. All are highly ionized with no measurable low-ionization ions like Si II or C II, and all appear to form in the quasar/host galaxy environments based on evidence for line locking, partial covering of the background light source, strong N V absorption, and/or roughly solar metallicities, and on the implausibility of such complexes forming in unrelated intervening galaxies. Most of the lines in all five complexes identify high-speed quasar-driven outflows at velocity shifts v≲-1000 km s^–1. Four of the complexes also have lines at smaller blueshifted velocities that might form in ambient interstellar clouds, low-speed outflows, or at feedback interfaces in the host galaxies where high-speed winds impact and shred interstellar clouds. The partial covering we measure in some of the high-speed outflow lines require small absorbing clouds with characteristic sizes <=1 pc or <=0.01 pc. The short survival times of these clouds require locations very close to the quasars, or cloud creation in situ at larger distances perhaps via feedback/cloud-shredding processes. The AAL complex in one quasar, J1008+3623, includes unusually narrow C IV systems at redshifted velocities 350≲v≲640 km s^–1 that are excellent candidates for gaseous infall toward the quasar, e.g., "cold-mode" accretion or a gravitationally bound galactic fountain.