Young Stellar Populations in the Collisional Ring Galaxy NGC 922
  We studied the star cluster population properties in the nearby collisional
ring galaxy NGC 922 using HST/WFPC2 photometry and population synthesis
modeling. We found that 69% of the detected clusters are younger than 7 Myr,
and that most of them are located in the ring or along the bar, consistent with
the strong Halpha emission. The images also show a tidal plume pointing toward
the companion. Its stellar age is consistent with pre-existing stars that were
probably stripped off during the passage of the companion. We compared the
star-forming complexes observed in NGC 922 with those of a distant ring galaxy
from the GOODS field. It indicates very similar masses and sizes, suggesting
similar origins. Finally, we found clusters that are excellent progenitor
candidates for faint fuzzy clusters.
