Star Clusters as Tracers of Interactions in Stephan's Quintet (Hickson
  Compact Group 92)
  Stephan's Quintet (SQ) is a compact group of galaxies that exhibits numerous
signs of interactions between its members. Using high resolution images of SQ
in B438, V606, and I814 bands from the Early Release Science project obtained
with the Wide Field Camera 3 on the Hubble Space Telescope, we identify 496
star cluster candidates (SCCs), located throughout the galaxies themselves as
well as in intergalactic regions. Our photometry goes \sim2 mag deeper and
covers an additional three regions, the Old Tail, NGC 7317, and the Southern
Debris Region, compared to previous work. Through comparison of the B438 - V606
and V606 - I814 colors of the star cluster candidates with simple stellar
population synthesis models we are able to constrain cluster ages. In
particular, the most massive galaxy of SQ, NGC 7319, exhibits continuous star
formation throughout its history, although at a lower rate over the past few
tens of Myr. NGC 7318 A/B and the Northern Star Burst region both show ongoing
active star formation; there are a number of star clusters that are younger
than 10 Myr. NGC 7318 A/B also features a peculiar gap in the color
distribution of the star clusters that can be used to date the onset of the
recent burst. The majority of the SCCs detected in the Young Tail were formed
150-200 Myr ago whereas the tight distribution of star cluster colors in the
Old Tail, allow us to constrain its age of formation to \sim400 Myr ago. The
star clusters in the Southern Debris region are seemingly divided into two
groups with ages of 50 and \sim500 Myr and virtually all of the SCCs detected
in NGC 7317 are over 2 Gyr old. Based on these ages, we estimate time intervals
for the interactions between SQ members that triggered the massive star cluster
formation.
