Probing High-Column Outflows in BALQSOs Using Metastable Helium
  Outflows are believed to be ubiquitous and fundamentally important in active
galaxies. Despite their importance, key physical properties of outflows remain
poorly unconstrained; this severely limits study of the acceleration process.
It is especially difficult to constrain the column density since most of the
lines are saturated. However, column densities can be measured using ions that
are expected to be relatively rare in the gas, since they are least likely to
be saturated. Phosphorus, specifically the PV doublet at 1118 and 1128A, is
generally regarded as a useful probe of high column densities because of its
low abundance. We have found that the metastable neutral helium triplet is an
equally valuable probe of high column densities in BALQSOs. The significant
advantage is that it can be observed in the infrared (HeI*10830) and the
optical (HeI*3889) bands from the ground in low-redshift (z<1.2) objects.
  We report the discovery of the first HeI*10830 BALQSO FBQS J1151+3822, and
discuss constraints on the column density obtained from the optical and IR HeI*
lines. In addition, a new observation revealing MgII and FeII absorption
provides further constraints, and Cloudy modeling of HeI*, MgII, and FeII
suggests that the difference between LoBALs and FeLoBALs is column density
along the line of sight.
