Detectability of nontrivial topologies

We study how the uncertainty in the cosmological parameters impacts on the detection of topological signals, focussing on three cubic torus universes and using three tests: the information content, the S/N statistic, and the Bayesian evidence. We find, within the concordance cosmological model, that 3D torus universes with a size of similar to 29 Gpc(3) or larger cannot be detected. For the toroidal models that can be detected, the detection significance is primarily influenced by Omega(Lambda), which enters both in the noise amplitude due to the Integrated Sachs-Wolfe effect and in the size of the causal horizon which limits the accessible fundamental domain. On large angular scales l < 40, only Omega(Lambda) significantly alters the detection for all three estimators considered here.