Wl. Freedman et al., DISTANCE TO THE VIRGO CLUSTER GALAXY M100 FROM HUBBLE-SPACE-TELESCOPEOBSERVATIONS OF CEPHEIDS, Nature, 371(6500), 1994, pp. 757-762
Accurate distances to galaxies are critical for determining the presen
t expansion rate of the Universe or Hubble constant (H-o). An importan
t step in resolving the current uncertainty in H-o is the measurement
of the distance to the Virgo cluster of galaxies. New observations usi
ng the Hubble Space Telescope yield a distance of 17.1 +/- 1.8 Mpc to
the Virgo cluster galaxy M100. This distance leads to a value of H-o =
80 +/- 17 km s(-1) Mpc(-1). A comparable value of H-o is also derived
from the Coma cluster using independent estimates of its distance rat
io relative to the Virgo cluster.