Arc statistics with realistic cluster potentials. IV. Clusters in different cosmologies
Abstract
We use numerical simulations of galaxy clusters in different cosmologies to study their ability to form large arcs. The cosmological models are: Standard CDM (SCDM; Omega_0 =1, Omega_ Lambda =0); tau CDM with reduced smallscale power (parameters as SCDM, but with a smaller shape parameter of the power spectrum); open CDM (OCDM; Omega_0 =0.3, Omega_ Lambda =0); and spatially flat, lowdensity CDM (Lambda CDM; Omega_0 =0.3, Omega_ Lambda =0.7). All models are normalised to the local number density of rich clusters. Simulating gravitational lensing by these clusters, we compute optical depths for the formation of large arcs. For large arcs with lengthtowidth ratio >=10, the optical depth is largest for OCDM. Relative to OCDM, the optical depth is lower by about an order of magnitude for Lambda CDM, and by about two orders of magnitude for S/tau CDM. These differences originate from the different epochs of cluster formation across the cosmological models, and from the nonlinearity of the strong lensing effect. We conclude that only the OCDM model can reproduce the observed arc abundance well, while the other models fail to do so by orders of magnitude.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 February 1998
 DOI:
 10.48550/arXiv.astroph/9707167
 arXiv:
 arXiv:astroph/9707167
 Bibcode:
 1998A&A...330....1B
 Keywords:

 GALAXIES: CLUSTERS: GENERAL;
 COSMOLOGY: DARK MATTER;
 COSMOLOGY: GRAVITATIONAL LENSING;
 COSMOLOGY: LARGESCALE STRUCTURE OF UNIVERSE;
 Astrophysics
 EPrint:
 15 pages including figures