  We experimentally and numerically investigate thermalization processes of a
trapped $^{87}$Rb Bose gas, initially prepared in a non-equilibrium state
through partial Bragg diffraction of a Bose-Einstein condensate (BEC). The
system evolves in a Gaussian potential, where we observe the destruction of the
BEC due to collisions, and subsequent growth of a new condensed fraction in an
oscillating reference frame. Furthermore, we occasionally observe the presence
of defects, which we identify as gray solitons. We simulate the evolution of
our system using the truncated Wigner method and compare the outcomes with our
experimental results.
