The relation between dynamics and star formation in barred galaxies
  We analyze optical and near-infrared data of a sample of 11 barred spiral
galaxies, in order to establish a connection between star formation and
bar/spiral dynamics. We find that 22 regions located in the bars, and 20
regions in the spiral arms beyond the end of the bar present azimuthal
color/age gradients that may be attributed to star formation triggering.
Assuming a circular motion dynamic model, we compare the observed age gradient
candidates with stellar populations synthesis models. A link can then be
established with the disk dynamics that allows us to obtain parameters like the
pattern speed of the bar or spiral, as well as the positions of resonance
radii. We subsequently compare the derived pattern speeds with those expected
from theoretical and observational results in the literature (e.g., bars ending
near corotation). We find a tendency to overestimate bar pattern speeds derived
from color gradients in the bar at small radii, away from corotation; this
trend can be attributed to non-circular motions of the young stars born in the
bar region. In spiral regions, we find that ~ 50% of the color gradient
candidates are "inverse", i.e., with the direction of stellar aging contrary to
that of rotation. The other half of the gradients found in spiral arms have
stellar ages that increase in the same sense as rotation. Of the 9 objects with
gradients in both bars and spirals, six (67%) appear to have a bar and a spiral
with similar Omega_p, while three (33%) do not.
