Cosmic flows and the expansion of the Local Universe from nonlinear
  phase-space reconstructions
  This work investigates the impact of cosmic flows and density perturbations
on Hubble constant $H_0$ measurements using nonlinear phase-space
reconstructions of the Local Universe (LU). In particular, we rely on 25
constrained N-body simulations of the LU using the 2MRS galaxy sample within
distances of 90 Mpc/h. These have been randomly extended up to volumes
enclosing 360 Mpc/h with augmented Lagrangian perturbation theory (750
simulations in total), accounting in this way for gravitational mode coupling
from larger scales, correcting for periodic boundary effects, and estimating
systematics of missing attractors ($\sigma_{\rm large}=134$ km/s). We report on
Local Group speed reconstructions, which are compatible with CMB-dipole
measurements: $|v_{\rm LG}|=685\pm137$ km/s. The direction $(l,b)=(260.5\pm
13.3,39.1\pm 10.4)^\circ$ is compatible with observations after considering the
variance of large scales. Accounting for large scales, our local bulk flow
estimations assuming a $\Lambda$CDM model are compatible with estimates based
on velocity data derived from the Tully-Fisher relation.
  We focus on low redshift supernova measurements ($0.01<z<0.025$), which have
been found to disagree with probes at larger distances. Our analysis indicates
that there are two effects contributing to this tension. First, the anisotropic
distribution of supernovae aligns with the velocity dipole and induces a
systematic boost in $H_0$. Second, a divergent region surrounding the Virgo
Supercluster is responsible for an additional positive bias in $H_0$. Taking
these effects into account yields a correction of $\Delta H_0=-1.76 \pm 0.21 $
km/s/Mpc, thereby reducing the tension between local probes and more distant
probes. Effectively $H_0$ is lower by about $2\%$.
