Cosmic flow around local massive galaxies
  Aims. We use accurate data on distances and radial velocities of galaxies
around the Local Group, as well as around 14 other massive nearby groups, to
estimate their radius of the zero-velocity surface, $R_0$, which separates any
group against the global cosmic expansion.
  Methods. Our $R_0$ estimate was based on fitting the data to the velocity
field expected from the spherical infall model, including effects of the
cosmological constant. The reported uncertainties were derived by a Monte Carlo
simulation.
  Results. Testing various assumptions about a location of the group
barycentre, we found the optimal estimates of the radius to be
$0.91\pm0.05$~Mpc for the Local Group, and $0.93\pm0.02$~Mpc for a synthetic
group stacked from 14 other groups in the Local Volume. Under the standard
Planck model parameters, these quantities correspond to the total mass of the
group $\sim (1.6\pm0.2) 10^{12} M_{\odot}$. Thus, we are faced with the
paradoxical result that the total mass estimate on the scale of $R_0 \approx
(3- 4) R_{vir}$ is only $~60$% of the virial mass estimate. Anyway, we conclude
that wide outskirts of the nearby groups do not contain a large amount of
hidden mass outside their virial radius.
