Nuclear Rings in Galaxies---A Kinematic Perspective
  We combine DensePak integral field unit and TAURUS Fabry-Perot observations
of 13 nuclear rings to show an interconnection between the kinematic properties
of the rings and their resonant origin. The nuclear rings have regular and
symmetric kinematics, and lack strong non-circular motions. This symmetry,
coupled with a direct relationship between the position angles and
ellipticities of the rings and those of their host galaxies, indicate the rings
are in the same plane as the disc and are circular. From the rotation curves
derived, we have estimated the compactness (v^2/r) up to the turnover radius,
which is where the nuclear rings reside. We find that there is evidence of a
correlation between compactness and ring width and size. Radially wide rings
are less compact, and thus have lower mass concentration. The compactness
increases as the ring width decreases. We also find that the nuclear ring size
is dependent on the bar strength, with weaker bars allowing rings of any size
to form.
