Deriving the pattern speed using dynamical modelling of gas flows in
  barred galaxies
  In this paper we analyse the methodology to derive the bar pattern speed from
dynamical simulations. The results are robust to the changes in the
vertical-scale height and in the mass-to-light (M/L) ratios. There is a small
range of parameters for which the kinematics can be fitted. We have also taken
into account the use of different type of dynamical modelling and the effect of
using 2-D vs 1-D models in deriving the pattern speeds. We conclude that the
derivation of the bar streaming motions and strength and position of shocks is
not greatly affected by the fluid dynamical model used. We show new results on
the derivation of the pattern speed for NGC 1530. The best fit pattern speed is
around 10 km/s/kpc, which corresponds to a R_cor/R_bar = 1.4, implying a slower
bar than previously derived from more indirect assumptions. With this pattern
speed, the global and most local kinematic features are beautifully reproduced.
However, the simulations fail to reproduce the velocity gradients close to some
bright HII regions in the bar. We have shown from the study of the Halpha
equivalent widths that the HII regions that are located further away from the
bar dust-lane in its leading side, downstream from the main bar dust-lane, are
older than the rest by 1.5-2.5 Myr. In addition, a clear spatial correlation
was found between the location of HII regions, dust spurs on the trailing side
of the bar dust-lane, and the loci of maximum velocity gradients parallel to
the bar major axis.
