Dynamical analysis of the cluster pair: A3407 + A3408
  We carried out a dynamical study of the galaxy cluster pair A3407 \& A3408
based on a spectroscopic survey obtained with the 4 meter Blanco telescope at
the CTIO, plus 6dF data, and ROSAT All-Sky-Survey. The sample consists of 122
member galaxies brighter than $m_R=20$. Our main goal is to probe the galaxy
dynamics in this field and verify if the sample constitutes a single galaxy
system or corresponds to an ongoing merging process. Statistical tests were
applied to clusters members showing that both the composite system A3407 +
A3408 as well as each individual cluster have Gaussian velocity distribution. A
velocity gradient of $\sim 847\pm 114$ $\rm km\;s^{-1}$ was identified around
the principal axis of the projected distribution of galaxies, indicating that
the global field may be rotating. Applying the KMM algorithm to the
distribution of galaxies we found that the solution with two clusters is better
than the single unit solution at the 99\% c.l. This is consistent with the
X-ray distribution around this field, which shows no common X-ray halo
involving A3407 and A3408. We also estimated virial masses and applied a
two-body model to probe the dynamics of the pair. The more likely scenario is
that in which the pair is gravitationally bound and probably experiences a
collapse phase, with the cluster cores crossing in less than $\sim$1 $h^{-1}$
Gyr, a pre-merger scenario. The complex X-ray morphology, the gas temperature,
and some signs of galaxy evolution in A3408 suggests a post-merger scenario,
with cores having crossed each other $\sim 1.65 h^{-1}$Gyr ago, as an
alternative solution.
