Nature and Origins of Rich Complexes of C IV Associated Absorption Lines
  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 3.1 to 4.4
with AAL complexes containing from 7 to 18 CIV 1548, 1551 systems in
high-resolution spectra. These complexes span velocity ranges $\lesssim$3600
km/s within $\lesssim$8200 km/s of the quasar redshifts. All are highly ionised
with no measurable low-ionisation ions like SiII or CII, 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 NV 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
$v\lesssim -1000$ km/s. 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 $\lesssim$1 pc or $\lesssim$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
CIV systems at redshifted velocities $350\lesssim v\lesssim640$ km/s that are
excellent candidates for gaseous infall towards the quasar, e.g., ''cold-mode"
accretion or a gravitationally-bound galactic fountain.
