Rendering Dark Energy Void
  Dark energy observations may be explained within general relativity using an
inhomogeneous Hubble-scale depression in the matter density and accompanying
curvature, which evolves naturally out of an Einstein-de Sitter (EdS) model. We
present a simple parameterization of a void which can reproduce concordance
model distances to arbitrary accuracy, but can parameterize away from this to
give a smooth density profile everywhere. We show how the Hubble constant is
not just a nuisance parameter in inhomogeneous models because it affects the
shape of the distance-redshift relation. Independent Hubble-rate data from age
estimates can in principle serve to break the degeneracy between concordance
and void models, but the data is not yet able to achieve this. Using the latest
Constitution supernova dataset we show that robust limits can be placed on the
size of a void which is roughly independent of its shape. However, the
sharpness of the profile at the origin cannot be well constrained due to
supernova being dominated by peculiar velocities in the local Universe. We
illustrate our results using some recently proposed diagnostics for the
Friedmann models.
