On The Formation Of Multiple Absorption Troughs In Broad Absorption Line
  QSOs
  We present theoretical CIV 1548,1550 absorption line profiles for QSOs
calculated assuming the accretion disk wind (ADW) scenario. The results suggest
that the multiple absorption troughs seen in many QSOs may be due to the
discontinuities in the ion balance of the wind (caused by X-rays), rather than
discontinuities in the density/velocity structure. The profiles are calculated
from a 2.5D time-dependent hydrodynamic simulation of a line-driven disk wind
for a typical QSO black hole mass, a typical QSO luminosity, and for a standard
Shakura-Sunyaev disk. We include the effects of ionizing X-rays originating
from within the inner disk radius by assuming that the wind is shielded from
the X-rays from a certain viewing angle up to 90o ("edge on"). In the shielded
region we assume constant ionization equilibrium, and thus constant line-force
parameters. In the non-shielded region we assume that both the line-force and
the C+3 populations are nonexistent. The model, at viewing angles close to the
angle that separates the shielded region and the non-shielded region, produces
absorption lines with multiple troughs. The steady nature of accretion disk
winds, in turn, may account for the steady nature of the absorption structure
observed in multiple-trough broad absorption line QSOs. The model parameters
are Mbh = 10^9 Msun and Ldisk = 10^47 erg s-1.
