Local Hole revisited: evidence for bulk motions and self-consistent
  outflow
  We revisit our mapping of the `Local Hole', a large underdensity in the local
galaxy redshift distribution that extends out to redshift, $z\approx0.05$ and a
potential source of outflows that may perturb the global expansion rate and
thus help mitigate the present `$H_0$ tension'. First, we compare local
peculiar velocities measured via the galaxy average redshift-magnitude Hubble
diagram, $\bar{z}(m)$, with a simple dynamical outflow model based on the
average underdensity in the Local Hole. We find that this outflow model is in
good agreement with our peculiar velocity measurements from $\bar{z}(m)$ and
not significantly inconsistent with SNIa peculiar velocity measurements from at
least the largest previous survey. This outflow could cause an $\approx2-3$\%
increase in the local value of Hubble's constant. Second, considering
anisotropic motions, we find that the addition of the outflow model may improve
the $\bar{z}(m)$ fit of a bulk flow where galaxies are otherwise at rest in the
Local Group frame. We conclude that the Local Hole plus neighbouring
overdensities such as the Shapley Supercluster may cause outflow and bulk
motions out to $\approx150$h$^{-1}$Mpc that are cosmologically significant and
that need to be taken into account in estimating Hubble's constant.
