BAL Outflow Contribution to AGN Feedback: Frequency of S iv Outflows in
  the SDSS
  We present a study of Broad Absorption Line (BAL) quasar outflows that show S
IV ?1063 and S IV* ?1073 troughs. The fractional abundance of S IV and C IV
peak at similar value of the ionization parameter, implying that they arise
from the same physical component of the outflow. Detection of the S IV* troughs
will allow us to determine the distance to this gas with higher resolution and
higher signal-to-noise spectra, therefore providing the distance and energetics
of the ubiquitous C IV BAL outflows. In our bright sample of 156 SDSS quasars
14% show C IV and 1.9% S IV troughs, which is consistent with a fainter
magnitude sample with twice as many objects. One object in the fainter sample
shows evidence of a broad S IV trough without any significant trough present
from the excited state line, which implies that this outflow could be at a
distance of several kpc. Given the fractions of C IV and S IV, we establish
firm limits on the global covering factor on S IV that ranges from 2.8% to 21%
(allowing for the k-correction). Comparison of the expected optical depth for
these ions with their detected percentage suggests that these species arise
from common outflows with a covering factor closer to the latter.
