Accretion disk wind as explanation for the broad-line region structure
  in NGC 5548
  Supermassive black holes in the centers of active galactic nuclei (AGN) are
surrounded by broad-line regions (BLRs). The broad emission lines seen in the
AGN spectra are emitted in this spatially unresolved region. We intend to
obtain information on the structure and geometry of this BLR based on observed
line profiles. We modeled the rotational and turbulent velocities in the
line-emitting region on the basis of the line-width FWHM and line dispersion
sigma_line of the variable broad emission lines in NGC5548. Based on these
velocities we estimated the height of the line-emitting regions above the
midplane in the context of their distances from the center. The broad emission
lines originate at distances of 2 to 27 light days from the center. Higher
ionized lines originate in the inner region (lesser equal 13 light days) in
specific filamentary structures 1 to 14 light days above the midplane. In
contrast, the Hbeta line is emitted in an outer (6 - 26 light days), more
flattened configuration at heights of 0.7 to 4 light days only above the
midplane. The derived geometry of the line-emitting region in NGC5548 is
consistent with an outflowing wind launched from an accretion disk.
