X-Ray Insights Into the Physics of Mini-BAL Quasar Outflows
  We examine the UV and X-ray properties of 256 radio-quiet SDSS quasars (QSOs)
observed in X-rays with Chandra and/or XMM-Newton in order to study the
relationship between QSOs with broad CIV absorption lines (BALs; width >2000
km/s) and those with CIV mini-BALs (here defined to have widths of 1000--2000
km/s). Our sample includes 42 BAL and 48 mini-BAL QSOs. The relative X-ray
brightness and hard spectral slopes of the mini-BAL population are, on average,
intermediate between those of BAL and non-BAL QSOs, as might be expected if
narrower and broader absorption line outflows are physically related. However,
a significant population of mini-BALs has outflow velocities higher than would
be expected for BAL QSOs of the same relative X-ray brightness. Consistenly
strong X-ray absorption is apparently not required to accelerate at least some
mini-BALs to high outflow velocities. Assuming the mini-BAL features are
correctly attributed to intrinsic CIV absorption, we suggest that their
observed properties may be explained if mini-BALs are "seeds" which can be
accelerated to form BALs when sufficient X-ray shielding is present.
  We also examine several QSOs with broad CIV absorption that have been
recently reported to be unusually X-ray bright. Such cases are frequently
mini-BAL QSOs, which as a population are generally brighter in X-rays than BAL
QSOs. Pointed XMM-Newton observations also suggest that these sources (or
unresolved neighbors) may have been previously observed in a high flux state.
