Recent Progress on the Cepheid Distance Scale with HST

摘要

I present some results and ongoing work on several projects using HST to improve the precision and accuracy of the Cepheid Distance Scale. The ultimate goal of these projects is to obtain a measurement of H_0 with a total uncertainty of 5% or less. A measurement with such precision and accuracy would have a significant impact on the determination of other cosmological parameters, such as the equation of state of dark energy.