TheHubble Space TelescopeKey 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$ Tully-Fisher relations based onCepheid distances to 21 galaxies within 25 Mpc, and 23 clusters within 10,000km/s. These relations have been applied to several distant cluster surveys inorder to derive a value for the Hubble constant, H0, mainly concentrating on anI-band all-sky survey by Giovanelli and collaborators which consisted of totalI magnitudes and 50% linewidth data for ~550 galaxies in 16 clusters. Forcomparison, we also derive the values of H0 using surveys in B-band and V-bandby Bothun and collaborators, and in H-band by Aaronson and collaborators.Careful comparisons with various other databases from literature suggest thatthe H-band data, whose magnitudes are isophotal magnitudes extrapolated fromaperture magnitudes rather than total magnitudes, are subject to systematicuncertainties. Taking a weighted average of the estimates of Hubble constantsfrom four surveys, we obtain H0 = 71 +- 4 (random) +- 7 (systematic) km/s/Mpc.We have also investigated how various systematic uncertainties affect the valueof H0 such as the internal extinction correction method used, Tully-Fisherslopes and shapes, a possible metallicity dependence of the Cepheidperiod-luminosity relation and cluster population incompleteness bias.Comment: 34 pages, 13 figure