The red extended structure of IC10, the nearest blue compact galaxy
  The Local Group starburst galaxy IC10 is the closest example of a blue
compact galaxy. Here, we use optical gi imaging from CFHT/MegaCam and near
infra-red JHK imaging from UKIRT/WFCAM to conduct a comprehensive survey of the
structure of IC10. We examine the spatial distribution of its resolved young,
intermediate and old stellar populations to large radius and low effective
surface brightness levels. Akin to other dwarfs with multiple populations of
different ages, stellar populations of decreasing average age are increasingly
concentrated in this galaxy. We find that the young, star-bursting population,
and the AGB population, are both offset from the geometric center of the older
RGB population by a few hundred parsecs, implying that the younger star
formation occurred significantly away from the center of the galaxy. The RGB
population traces an extended structure that is typical of blue compact
galaxies, with an effective radius of ~5.75 arcmins (~1.25 kpc). These
measurements show that IC10 is much more extended than has previously been
realized, and this blue compact galaxy is one of the most extended dwarf
galaxies in the Local Group. The outermost isophotes of this galaxy are very
regular in shape and essentially circular in morphology. Based on this
analysis, we do not find any evidence to suggest that IC10 has undergone a
recent, significant, interaction with an unknown companion.
