The Hubble space telescope key project on the extragalactic distance scale. XXIV. The calibration of tully-fisher relations and the value of the Hubble constant

This paper presents the calibration of BVRIH_-0.5 Tully-Fisher relations based on Cepheid distances to 21 galaxies within 25 Mpc and 23 clusters within 10,000 km s^-1. These relations have been applied to several distant cluster surveys in order to derive a value for the Hubble constant, H₀, mainly concentrating on an I-band all-sky survey by Giovanelli and collaborators, consisting of total I magnitudes and 50% line width data for ∼550 galaxies in 16 clusters. For comparison, we also derive the values of H₀ using surveys in the B and V bands by Bothun and collaborators, and in H band by Aaronson and collaborators. Careful comparisons with various other databases from the literature suggest that the H-band data, which have isophotal magnitudes extrapolated from aperture magnitudes rather than total magnitudes, are subject to systematic uncertainties. Taking a weighted average of the estimates of Hubble constants from four surveys, we obtain H₀ = 71 ± 4 (random) ± 7 (systematic). We have also investigated how the value of H₀ is affected by various systematic uncertainties, such as the internal extinction correction method used, Tully-Fisher slopes and shapes, a possible metallicity dependence of the Cepheid period-luminosity relation, and cluster population incompleteness bias.