Cosmic vector for dark energy: constraints from SN, CMB and BAO
  It has been recently shown that the presence of a vector field over
cosmological scales could explain the observed accelerated expansion of the
universe without introducing neither new scales nor unnatural initial
conditions in the early universe, thus avoiding the coincidence problem. Here,
we present a detailed analysis of the constraints imposed by SNIa, CMB and BAO
data on the vector dark energy model with general spatial curvature. We find
that contrary to standard cosmology, CMB data excludes a flat universe for this
model and, in fact, predicts a closed geometry for the spatial sections. We see
that CMB and SNIa Gold data are perfectly compatible at the 1-sigma level,
however SNIa Union dataset exhibits a 3-sigma tension with CMB. The same level
of tension is also found between SNIa and BAO measurements.
