Cosmic microwave anisotropies in an inhomogeneous compact flat universe

The anisotropies of the cosmic microwave background (CMB) are computed for the half-turn space E-2, which represents a compact flat model of the Universe, i.e. one with finite volume. This model is inhomogeneous in the sense that the statistical properties of the CMB depend on the position of the observer within the fundamental cell. It is shown that the half-turn space describes the observed CMB anisotropies on large scales better than the concordance model with infinite volume. For most observer positions, it matches the temperature correlation function slightly better than the well-studied 3-torus topology.