| Abstract | We describe a program of surface brightness fluctuation (SBF) measurements for determining galaxy distances. This paper presents the photometric calibration of our sample and of SBF in general. Basing our zero point on observations of Cepheid variable stars, we find that the absolute SBF magnitude in the Kron-Cousins I band correlates well with the mean (V - I)0 color of a galaxy according to M̄I=(-1.74+/-0.07)+(4.5+/-0.25)[(V-I)0-1.15] for 1.0 < (V - I) < 1.3. This agrees well with theoretical estimates from stellar population models. Comparisons between SBF distances and a variety of other estimators, including Cepheid variable stars, the planetary nebula luminosity function (PNLF), Tully-Fisher (TF), Dn-σ, SN II, and SN Ia, demonstrate that the calibration of SBF is universally valid and that SBF error estimates are accurate. The zero point given by Cepheids, PNLF, TF (both calibrated using Cepheids), and SN II is in units of megaparsecs; the zero point given by TF (referenced to a distant frame), Dn-σ, and SN Ia is in terms of a Hubble expansion velocity expressed in km s-1. Tying together these two zero points yields a Hubble constant of H0=81+/-6 km s-1 Mpc-1 . As part of this analysis, we present SBF distances to 12 nearby groups of galaxies where Cepheids, SN II, and SN Ia have been observed. Observations in part from the Michigan-Dartmouth-MIT (MDM) Observatory. |
