Redshift and gauge choice
  We show that a specific gauge choice comes extremely close to defining a
frame whose preferred observers see a dipole-free CMB. In this gauge the metric
is the product of a scale factor depending on all spacetime coordinates, and a
metric featuring an expansion-free geodesic timelike vector field. This setup
facilitates the computation of redshift and other distance measures and
explains why we can have a highly isotropic CMB despite large inhomogeneities.
