Massive star formation in galaxies with excess UV emission
  From an analysis of almost 2000 GALEX images of galaxies with morphological
types ranging from E to Sab, we have found a significant subset (28%) that show
UV emission outside $R_{25}$. We have obtained H$\alpha$ imaging of ten such
galaxies, and find that their star formation rates are similar in the UV and in
H$\alpha$, with values ranging from a few tenths to a few $M_{\odot} $ yr$
^{-1} $. Probably because our sample selection is biased towards star-forming
galaxies, these rates are comparable to those found in disk galaxies, although
the star formation rates of the elliptical galaxies in our sample are well
below $1\,M_{\odot} $ yr$ ^{-1}$. We confirm that the extended UV emission in
our sample is caused by massive star formation in outer spiral arms and/or
outer (pseudo) rings, rather than by alternative mechanisms such as the UV
upturn.
