Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

of galaxies with dust disks (N=8/11), 60% of galaxies with dust lanes (N=3/5), 67%
of galaxies with irregular dust (N=2/3) and 0% of galaxies with no dust (N=0/2).
If we make a flux cut in Hα we find broad components in 40% of nuclei with
1×10 −15 ≤ F(Hα) ≤ 1×10 −14 , in 55% of nuclei with 1×10 −14 ≤ F(Hα) ≤ 5×10 −14
and in 100% of nuclei with F(Hα) ≥ 5 × 10 −14 . This detection trend with flux is
reflected in Figure 3.26. This suggests that the detection of nuclear broad components
is somewhat flux (and therefore signal to noise) dependent across the sample.
The broad components could originate either as an artifact of attempting to fit
Gaussians to non-Gaussian line profiles, or from a physical source – such as a broad
line region or a change in the characteristics of the gas as the inner regions of the
disk are approached.
We detect broad components only in the central few pixels, this could be a con-
sequence of either the fall in signal to noise or that the component is an unresolved
source. It is important to note as a consequence of this, that fitting single Gaus-
sians to each line samples a different part of the line shape as the central pixels are
approached.
In Table 3.31 we show the mean properties of the broad components and compare
84