Star Formation History and the Measurement of Galaxy Properties: Insights from Nearby Dwarf Galaxies

The star formation history (SFH) of different galaxies is a key component of theories of galaxy evolution, determining the buildup of stellar mass over cosmic time. The SFH also affects the conversion between luminosity and star formation rate or stellar mass, both critical quantities in galaxy evolution studies. The SFH depends on the growth of structure in the universe and mechanisms of feedback, which may be particularly effective in low-mass dwarf galaxies. However, measurement of the star-formation history of individual galaxies on the relevant timescales is exceedingly difficult. I will present a method for constraining the typical recent SFH of dwarf galaxies via the comparison of star formation tracers in a volume limited sample of galaxies. Additionally, using a small sample of dwarf galaxies with well-constrained SFH, I will quantify the effect of SFH on traditional measures of stellar mass and star formation rate. The color-magnitude diagram of resolved stars in these galaxies, obtained with HST, yield the best contraints on the SFH currently possible.