Statistics of interacting galaxies at z~0.7
  We present the results of our analysis of the frequencies of galaxies with
tidal tails and M51-type galaxies in several deep fields of the Hubble Space
Telescope (HDF-N, HDF-S, HUDF, GOODS, GEMS). In total, we have found about
seven hundred interacting galaxies at redshifts z<1.5 in these fields. At
z<0.7, the observed space densities of galaxies with tidal structures and
M51-type galaxies have been found to increase as $\propto (1+z)^m$, where
m~2.6. According to our estimates, over the last 6-7 Gyr, i.e., at z<0.7, about
a third of the galaxies with M(B)<-18 mag must have undergone strong
gravitational perturbations and mergers and ~1/10-1/5 of the galaxies have
accreted relatively low-mass nearby satellites typical of M51-type galaxies.
The possible decrease in the timescale on which a distant galaxy appears
peculiar with growing z can increase considerably the estimated rate of
mergers.
