A test of arm induced star formation in spiral galaxies from near-IR and   H\alpha imaging
  We have imaged a sample of 20 face-on spiral galaxies in H\alpha and in the near-IR K-band (2.2 microns), in order to determine the location and strength of star formation with respect to perturbations in the old stellar population. We found that star formation rates are significantly enhanced near K-band arms. If K-band light is dominated by emission from old stars, this shows that density waves trigger star formation. However, no significant correlation was found between the global underlying disk properties of spiral galaxies and their total star formation rates. 
M.S. Seigar (Imperial College) and P.A. James (Liverpool John Moores   University)