Relics of spatial curvature in the primordial non-gaussianity
  We study signatures in the Cosmic Microwave Background (CMB) induced by the
presence of strong spatial curvature prior to the epoch of inflation which
generated our present universe. If inflation does not last sufficiently long to
drive the large-scale spatial curvature to zero, then presently observable
scales may have left the horizon while spatial slices could not be approximated
by a flat, Euclidean geometry. We compute corrections to the power spectrum and
non-gaussianity of the CMB temperature anisotropy in this scenario. The power
spectrum does not receive significant corrections and is a weak diagnostic of
the presence of curvature in the initial conditions, unless its running can be
determined with high accuracy. However, the bispectral non-gaussianity
parameter f_NL receives modifications on the largest observable scales. We
estimate that the maximum signal would correspond to f_NL ~ 0.3, which is out
of reach for present-day microwave background experiments.
