We review the increasing evidence for the cosmological relevance of the cold local Hubble flow .
New observations , N-body simulations and other theoretical arguments are discussed , supporting our previous suggestion that the cosmological vacuum or uniform dark energy can have locally observable consequencies , especially a lower velocity scatter in DE dominated regions .
The apparent contradiction between the slight dependence of the growth factor on \Omega _ { \Lambda } and the significant influence of dark energy in realistic N-body calculations is clarified .
An interesting new result is that in the standard \Lambda cosmology , gravitation dominates around a typical matter fluctuation up to about the correlation length r _ { 0 } , and we tentatively link this with the high pairwise velocity dispersion on scales up to several Mpc , as measured from galaxy redshift-space correlations .
Locally , the smooth Hubble flow on similar scales is consistent with N-body simulations including \Omega _ { \Lambda } \approx 0.7 and a low density contrast in the Local Volume , which make it generally vacuum-dominated beyond 1 - 2 Mpc from galaxies and groups .
We introduce a useful way to view the Hubble flow in terms of ” zero gravity ” spheres around galaxies : e.g. , a set of non-intersecting spheres , observed to be expanding , actually participates in accelerating expansion .
The observed insensitiveness of the local velocity dispersion to galaxy mass is explained as an effect of the vacuum , too .