The dependence of the formation redshift of clusters of galaxies on the cosmological constant is discussed on the basis of recent measurements of gravitational masses and radii of galaxy clusters by X-ray astronomy methods. For a flat CDM model with several different values of the cosmological constant, the number density of galaxy clusters as a function of redshift has been calculated. Comparing the derived number density at redshift z = 0 with observed value, the allowed spectrum parameter Γ is found to be limited in the range of 0.15 - 0.32. The authors' calculation also shows that if Γ and/or ΩΛ was larger, much more clusters of galaxies should have been formed at high redshift.
Acta Astrophysica Sinica
- Pub Date:
- July 1997
- Cosmological Constant: Clusters of Galaxies