Planetary nebulae as standard candles. V. The distance to the Virgo Cluster

The O III forbiden 5007-A line fluxes of 486 planetary nebula candidates in six early-type galaxies (NGC 4374, 4382, 4406, 4472, 4486, and 4649) in the core of the Virgo Cluster are identified and measured. Following the procedures and calibrations outlined in previous papers in this series, the observed planetary nebula luminosity functions are compared to an empirical model based on the planetary nebulae in M31, and the distances to the galaxies are derived to be 15.7, 14.4, 15.7, 13.9, 14.5, and 14.2 Mpc. These distances exhibit superb agreement with a dispersion of only 0.8 Mpc and suggest that the cluster depth is less than 2 Mpc. Most importantly, the distances are totally uncorrelated with parent galaxy metallicity, color, UV flux, or Hubble type. 76 refs