Bar pattern speed and position of the circumnuclear ring in NGC 1097
  We present the first galactic-scale model of the gas dynamics of the
prototype barred Seyfert 1 galaxy NGC1097. We use large scale FaNTOmM
Fabry-Perot interferometric data covering the entire galactic disc and combine
the distribution and kinematics maps with high resolution two-dimensional
spectroscopy from the Gemini telescope. We build a dynamical model for the
gravitational potential by applying the analytic solution to the equations of
motion, within the epicyclic approximation. Our model reproduces all the
significant kinematic and structural signatures of this galaxy. We find that
the primary bar is 7.9+/-0.6 kpc long and has a pattern speed of 36 +/- 2 km
s^-1 kpc^-1. This places the corotation radius at 8.6 +/-0.5 kpc, the outer
Lindblad resonance at 14.9+/-0.9 kpc and two inner Lindblad resonances at
60+/-5 pc and 2.9+/-0.1 kpc. These derivations lead to a ratio of the
corotation radius over bar length of 1.0--1.2, which is in agreement with the
predictions of simulations for fast galaxy bars. Our model presents evidence
that the circumnuclear ring in this galaxy is not located near any of the
resonance radii in this galaxy. The ring might have once formed at the outer
inner Lindblad resonance radius, and it has been migrating inward, toward the
centre of the galactic gravitational potential.
