Destructible Bars in Disk Galaxies under the Dynamical Influence of a
  Massive Central Black Hole
  The characteristics of the galactic bars that are prone to suffer a damaging
impact from a massive central black hole are examined using flat stellar disks.
We construct three disk model groups that consist of exponential disks with one
type of velocity distribution and Kuzmin-Toomre disks with two different types
of exact equilibrium distribution function. For each disk model group, three
disks that have different typical Toomre's Q values are evolved to form bars
through dynamical instability. Once a bar is fully developed, a black hole
(BH), whose mass is 1% of the disk mass, is adiabatically added at the center
of the disk. Our results show that lower-amplitude bars, that is, weaker bars
are dissolved more easily by that BH. We have found that this destructibility
is rooted in the characteristic feature that the bar formed spontaneously
becomes shorter in length and rounder in shape with decreasing bar amplitude.
Since such weaker bars are found to originate from colder disks in each disk
model group, it follows that for a given form of velocity structure, the
coldness of an initial disk determines whether the bar produced in that disk is
favorable to dissolution induced by a massive central BH. In addition, the
existence of bar-dissolved galaxies of the kind studied here is also discussed.
