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 ∼29  Gpc³ or larger cannot be detected. For the toroidal models that can be detected, the detection significance is primarily influenced by Ω_Λ, 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 Ω_Λ significantly alters the detection for all three estimators considered here.