The Cosmological Constant $\hat{I}›$, the Age of the Universe and Dark Matter: Clues from the Ly$\hat{I}\pm$-Forest

Abstract

Evidence for a positive cosmological constant $\hat{I}›$, derived from the Ly$\hat{I}\pm$-forest in high-resolution spectra of quasars, leads to a closed, low-density, $\hat{I}›$-dominated universe. The analysis is based on the assumption of a universal shell structure expanding predominantly with the Hubble flow. Supporting evidence comes from two pairs of very wide absorption lines in the spectra of two quasars separated by 8 arcmin on the sky. These results contradict the higher values of the density parameter $\hat{I}{\text{c◯}}_{M,0}$ derived, for example, from clusters of galaxies by the pure gravitational instability theory. Implications thereof and for the amount of non-baryonic dark matter in the universe are discussed with some $\hat{I}›$-dominated models, in particular with $\hat{I}{\text{c◯}}_{M,0}=0.2$ and with pure baryonic models. The evidence points to low-density, closed models with spherical metric, expanding forever.

16 pages, latex, 9 embedded figures. To appear in the proceedings of the Second International Workshop on Dark Matter (DARK98), eds. H.V. Klapdor-Kleingrothaus and L. Baudis