Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

used) for the zero black hole mass model. However we anticipate that a black hole is
present in these galaxies meaning the observed slope should be steeper if the disk is
stable. If flow is taking place then it may be possible to detect the signature across
the minor axis, and indeed in Figure 4.29 (for NGC 2329) it is possible to see positive
and negative velocity features in the side slit positions.
In Table 4.6 we also list the black hole masses predicted by the relationship fit
by Merritt & Ferrarese (2001). Though the kinematics will not allow us to fit exact
models for the black hole mass, we can see that the ranges derived from the kine-
matic signatures in the central regions lead to black hole masses that are generally
compatible with the M• − σc relation. In Figure 4.46 we plot our results on top
of the reliable black hole estimates and M• − σc relation as presented in Chapter
1. Though the agreement is generally good (for galaxies where we give the range of
masses 1×10 8 M⊙ < M• < 9×10 8 M⊙ and where M• ∼ > 9×108 M⊙ in particular), the
galaxies with an upper limit around 1 × 10 8 M⊙ lie somewhat below their predicted
values.
4.4.2 Settling of the gas into a thin disk
In Steiman-Cameron & Durisen (1986) the authors present a summary of results
relating to the settling of gas disks in elliptical galaxies. Through analytical and
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