The SBF survey of galaxy distances - J.L. Tonry

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 , SNII, and SNIa, indicate 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 SNII is in units of Mpc; the zero point given by TF (referenced to a distant frame), Dn , and SNIa is in terms of a Hubble expansion velocity expressed in km/s. Tying together these two zero points yields a Hubble constant of (0.2) As part of this analysis, we present SBF distances to 12 nearby groups of galaxies where Cepheids, SNII, and SNIa have been observed. The results presented in this conference contribution will mostly be published soon in the ApJ (Tonry, Blakeslee, Ajhar, and Dressler 1997, TBAD97). Accordingly, there are few references to the literature, since they can be found in that source, along with all the details which are only treated very superficially here.