The Origin of Intergalactic Light in Compact Groups of Galaxies
  We investigate the origin of intergalactic light (IGL) in close groups of
galaxies. IGL is hypothesized to be the byproduct of interaction and merger
within compact groups. Comparing the X-ray point source population in our
sample of compact groups that have intergalactic light with compact groups
without IGL, we find marginal evidence for a small increase in ultra-luminous
X-ray sources (ULXs). There is also a significant bias towards lower luminosity
high mass X-ray binaries (HMXRBs). We interpret this as an indication that
groups with visible IGL represent a later evolutionary phase than other compact
groups. They have galaxies characterized by quenching of star formation (lower
star formation rate (SFR) inferred from lower HMXRB luminosity) after stellar
material has been removed from the galaxies into the intergalactic medium,
which is the source of the IGL. We conclude that the presence of an increased
fraction of ULXs is due to past interaction and mergers within groups that have
IGL.
