Collective motion in selected central collisions of Au on Au at 150A MeV

Using the FOPI facility at GSI Darmstadt complete data of Au on Au collisions at 150[ital A] MeV were collected for charged products ([ital Z]=1--15) at laboratory angles 1[degree][le][Theta][sub lab][le]30[degree]. Central collisions were selected by applying various criteria. The kinetic energy spectra of fragments from an isolated midrapidity source are investigated in detail for center-of-mass angles 25[degree][le][Theta][sub c.m.][le]45[degree]. The heavy products ([ital Z][ge]3) are used to determine the collective energy which is found to be at least 10[ital A] MeV.