  We consider one-dimensional systems of self-gravitating sticky particles with
random initial data and describe the process of aggregation in terms of the
largest cluster size L_n at any fixed time prior to the critical time. The
asymptotic behavior of L_n is also analyzed for sequences of times tending to
the critical time. A phenomenon of phase transition shows up, namely, for small
initial particle speeds (``cold'' gas) L_n has logarithmic order of growth
while higher speeds (``warm'' gas) yield polynomial rates for L_n.
