Year: 1996
Type: article
Abstract: Cepheid variables are used to derive a Virgo cluster distance of 16.0 ± 1.5 Mpc. In conjunction with the mean Coma radial velocity and the well-established Coma/Virgo distance ratio, this yields a Hubble parameter H 0 = 81 ± 8 km s -1 Mpc -1 . By combining this value with an age of the Universe >~ 16.8 ± 2.1 Gyr, that is derived from the metal-poor globular cluster M92, one obtains f (Omega, Lambda) >~ 1.39 ± 0.22. This value is only marginally consistent with an Einstein-de Sitter universe with Omega = 0 and Lambda = 0, which has f =1. An Einstein-de Sitter universe with Omega = 1 and Lambda = 0, for which f = 2/3, appears to be excluded at the 3-sigma level. It is shown that some recent small values of H 0 may have resulted from the large intrinsic dispersion in the linear diameters of galaxies, and from the fact that well-observed supernovae of Type Ia exhibit a luminosity range of ~20 at maximum light. A representative sample of recent estimates of H 0 is given in Table 1. The median value of the Hubble parameter from the data in this table is H 0 = 72 km s -1 Mpc -1 from which f(Omega,Lambda) >~ 1.24.
DOI: 10.1086/133839
Author: Sidney van den Bergh
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2071919956