Steps toward the Hubble Constant. IX. The Cosmic Value of H 0 Freed from All Local Velocity Anomalies

The velocity which the Virgo Cluster would have if it were freed from all local anomalies relative to the cosmological Machian frame is determined by bringing the remote velocity frame to the Virgo Cluster distance. Three independent methods are used to accomplish this: (1) distances of 17 "remote" clusters are determined relative to Virgo by a number of independent methods; the equation of the Hubble diagram correlation that relates redshift and the distance modulus difference from Virgo is then read for its velocity value at the modulus difference of {DELTA}(m-M) = 0.00; (2) a similar calculation is made using apparent magnitudes of first-ranked cluster galaxies in relatively distant clusters, and (3) the same calculation is made using distant supernovae of Type Ia. The resulting velocity of Virgo, called the "cosmic expansion velocity freed from local velocity anomalies" is v_cosmic_(Virgo) = 1144 +/- 18 km s^-1^. The distance to the Virgo Cluster core is determined from six independent methods using recent data, giving (m-M) = 31.70 +/- 0.09, or D = 21.9 +/- 0.9 Mpc. Combining the cosmic Virgo velocity with this distance, which now is of unprecedented accuracy, gives the Hubble constant to be H_0_ = 52 +/- 2 km s^-1^ Mpc^-1^. If a still more accurate distance D (in Mpc) to the Virgo Cluster core becomes available, the calculated Hubble constant will be changed to H_0_ = 52(21.9/D) km s^-1^ Mpc^-1^. As a by-product (but which does not enter the method devised here to find H_0_), we determine the infall velocity of the Local Group toward Virgo (the retarded expansion effect) to be 168 +/- 50 km s^-1^. A firm lower limit to H_0_ can be obtained by putting this infall velocity to zero so that v(Virgo)_cosmic_ = v(Virgo)_observed_ = 976 +/- 45 km s^-1^. For this limiting case (which is physically unreal unless the Virgo pull is zero, and therefore {DELTA} = 0) the lower limit to the global value of H_0_ becomes H_0(min)_ = (45 +/- 3)(21.9/D) km s^-1^ Mpc^-1^.