Large-Scale Outer Rings of Early-type Disk Galaxies
  We have searched for presence of current star formation in outer stellar
rings of early-type disk (S0-Sb) galaxies by inspecting a representative sample
of nearby galaxies with rings from the recent Spitzer catalog ARRAKIS (Comeron
et al. 2014). We have found that regular rings (of R-type) reveal young stellar
population with the age of less than 200~Myr in about half of all the cases,
while in the pseudorings (open rings, R'), which inhabit only spiral galaxies,
current star formation proceeds almost always.
