Supernovae observations and cosmic topology

Context. Two fundamental questions regarding our description of the Universe concern the geometry and topology of its 3-dimensional space. While geometry is a local characteristic that gives the intrinsic curvature, topology is a global feature that characterizes the shape and size of the 3-space. The geometry constrains, but does not dictate, the spatial topology. Aims. We show that besides determining the spatial geometry, the knowledge of the spatial topology allows us to place tight constraints on the density parameters associated with dark matter (Ωm) and dark energy (ΩΛ). Methods. By using the Poincaré dodecahedral space as the observable spatial topology, we reanalyze the current type Ia supernovae (SNe Ia) constraints on the density parametric space Ωm −ΩΛ. Results. From this SNe Ia plus cosmic topology analysis, we find best-fit values for the density parameters that are in agreement with a number of independent cosmological observations.