On arcs and [Omega]

• Verfasst von: Bartelmann, Matthias [VerfasserIn]
• Titel: On arcs and [Omega]
• Verf.angabe: M. Bartelmann, A. Huss, J.M. Colberg, A. Jenkins, F.R. Pearce
• Fussnoten: Im Titel ist Omega als griechischer Buchstabe dargestellt ; Gesehen am 28.09.2017
• Titel Quelle: Enthalten in: De.arxiv.org
• Jahr Quelle: 1997
• Band/Heft Quelle: (1997) Artikel-Nummer 9709229, 4 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1563898586

Abstract

The gravitational lens effect of galaxy clusters can produce large arcs from source galaxies in their background. Typical source redshifts of ~ 1 require clusters at z ~ 0.3 for arcs to form efficiently. Given the cluster abundance at the present epoch, the fewer clusters exist at z ~ 0.3 the higher Omega_0 is, because the formation epoch of galaxy clusters strongly depends on Omega_0. In addition, at fixed Omega_0, clusters are less concentrated, and hence less efficient lenses, when the cosmological constant is positive, Omega_Lambda > 0. Numerical cluster simulations show that the expected number of arcs on the sky is indeed a sensitive function of Omega_0 and Omega_Lambda. The numerical results are compatible with the statistics of observed arcs only in a universe with low matter density, Omega_0 ~ 0.3, and zero cosmological constant. Other models fail by one or two orders of magnitude, rendering arc statistics a sensitive probe for cosmological parameters.