Cluster and field star formation in late-type dwarf galaxies
Monica Tosi, Alessandra Aloisi, Roeland van der Marel
In the local Universe, late-type dwarf galaxies (dwarf irregulars and blue compact dwarfs) are the places where starbursts are mostly found, and thus the ideal laboratories to probe the star formation process. The high spatial resolution and high sensitivity of the Hubble Space Telescope (HST) offers the possibility of studying these systems in detail, both in terms of their star formation histories from the color-magnitude diagrams of the resolved "field" stars, and in terms of the properties of their unresolved cluster population. The two approaches are complementary to answer key questions, such as, are field and cluster formation actually distinct mode of star formation? What is the fraction of stars that form in clusters? How important is cluster disruption? Can clusters be used as tracers of galactic star formation histories?
Within this framework, I will present our recent results on the cluster and field star formation in some late-type dwarf galaxies (NGC 1705, IZw 18, NGC 4449) based on the analysis of deep HST data.