A polar+equatorial wind model for broad absorption line quasars: I.
  Fitting the C IV BAL profiles
  Despite all the studies, the geometry of the wind at the origin of the
blueshifted broad absorption lines (BAL) observed in nearly 20% of quasars
still remains a matter of debate. We want to see if a two-component
polar+equatorial wind geometry can reproduce the typical BAL profiles observed
in these objects. We built a Monte Carlo radiative transfer code (called MCRT)
to simulate the line profiles formed in a polar+equatorial wind in which the
photons, emitted from a spherically symmetric core are resonantly scattered.
Our goal is to reproduce typical C IV line profiles observed in BAL quasars and
to identify the parameters governing the line profiles. The two-component wind
model appears to be efficient in reproducing the BAL profiles from the P
Cygni-type profiles to the more complex ones. Some profiles can also be
reproduced with a pole-on view. Our simulations provide evidence of a
high-velocity rotation of the wind around the polar axis in BAL quasars with
non P Cygni-type line profiles.
