The Extragalactic Distance Scale Without Cepheids. II. Surface Brightness Fluctuations

Abstract

Distances of galaxies in the Hubble Space Telescope (HST) Key Project are based on the Cepheid period-luminosity relation. An alternative basis is the tip of the red giant branch (TRGB). Using archival HST data, we calibrate surface brightness fluctuations using 16 galaxies with TRGB branch measurements. The TRGB and Cepheid distance scales are shown to be consistent to approximately ±6% in the Hubble constant.