Absorption-line Environments of High-redshift BOSS Quasars
  The early stage of massive galaxy evolution often involves outflows driven by
a starburst or a central quasar plus cold mode accretion (infall), which adds
to the mass build-up in the galaxies. To study the nature of these infall and
outflows in the quasar environments, we have examined the correlation of narrow
absorption lines (NALs) at positive and negative velocity shifts to other
quasar properties, such as their broad absorption-line (BAL) outflows and
radio-loudness, using spectral data from SDSS-BOSS DR12. Our results show that
the incidence of associated absorption lines (AALs) and outflow AALs is
strongly correlated with BALs, which indicates most AALs form in quasar-driven
outflows. Multiple AALs are also strongly correlated with BALs, demonstrating
quasar outflows tend to be highly structured and can create multiple gas
components with different velocity shifts along our line of sight. Infall AALs
appear less often in quasars with BALs than quasars without BALs. This suggests
that BAL outflows act on large scale in host galaxies and inhibit the infall of
gas from the IGM, supporting theoretical models in which quasar outflow plays
an important role in the feedback to host galaxies. Despite having larger
distances, infall AALs are more highly ionized than outflow AALs, which can be
attributed to the lower densities in the infall absorbers.
