  Recent studies have shown that starburst dwarf galaxies have steeply rising
rotation curves in their inner parts, pointing to a close link between the
intense star formation and a centrally concentrated mass distribution (baryons
and dark matter). More quiescent dwarf irregulars typically have slowly rising
rotation curves, although some "compact" irregulars with steep, inner rotation
curves exist. We analyze archival Hubble Space Telescope images of two nearby
"compact" irregular galaxies (NGC 4190 and NGC 5204), which were selected
solely on the basis of their dynamical properties and their proximity. We
derive their recent star-formation histories by fitting color-magnitude
diagrams of resolved stellar populations, and find that the star-formation
properties of both galaxies are consistent with those of known starburst
dwarfs. Despite the small sample, this strongly reinforces the notion that the
starburst activity is closely related to the inner shape of the potential well.

Astrophysics of Galaxies