HST/COS Observations of Quasar Outflows in the 500-1050 \AA\ Rest Frame:
  I. The Most Energetic Outflows in the Universe and Other Discoveries
  The Hubble Space Telescope/Cosmic Origins Spectrograph (COS) has opened a new
discovery space for studying quasar absorption outflows and their contribution
to AGN feedback. Specifically, COS provides high-quality far-ultraviolet (FUV)
spectra covering the diagnostic-rich 500-1050 Angstrom rest frame (hereafter,
EUV500) of medium redshift objects. The quality and quantity of EUV500
diagnostic troughs allow us to probe the very high-ionization phase, which
carries 90% or more of the outflowing material, as well as to determine the
distance of most outflows from the central source ($R$). The first objective is
impossible to achieve with ground-based spectra, and $R$ can be measured in
only $\sim$1% of them. Here, we summarize the main results of the first
dedicated survey of such outflows, including the following:
  1) Measurements of the three most energetic outflows to date, which can be
the main agents for AGN feedback processes in the environments of the host
galaxies.
  2) All the outflows have a very high-ionization component, similar to the one
found in warm absorbers, which carries most of the outflow's kinetic
luminosity. This finding suggests that all the high-ionization outflows
observed from the ground also have a similar undetected very high-ionization
component.
  3) Of the 13 studied EUV500 outflows, 9 have $100<R<2000$ parsecs, 2 have
$5<R<20$ parsecs, 1 has $0.05<R<50$ parsecs, and in 1 case, $R$ cannot be
determined.
  4) One of the outflows has the largest velocity shift (1550 km s$^{-1}$) and
acceleration (1.5 cm s$^{-2}$) measured to date. This outflow is physically
similar to the fast X-ray outflow detected in quasar PG 1211+143.
