The Virgo Cluster

Abstract

In the era of precision cosmology, the Virgo cluster takes on a new role in the cosmic distance scale. Its traditional role of testing the consistency of secondary distance indicators is replaced by an ensemble of distance measurements within the Local Supercluster, united by a velocity-field model obtained from a reconstruction based on redshift surveys. The Wilkinson Microwave Anisotropy Probe (WMAP) leads us to see the Hubble constant as one of six parameters in a standard model of cosmology with considerable covariance among parameters. Independent experiments, such as WMAP , the Hubble Space Telescope Key Project on the Extragalactic Distance Scale, and their successors constrain these parameters.