We are much indebted to Lars Hernquist for generously providing the TREESPH code, and to Teije de Jong and Peter Barthel for many stimulating discussions. We thank the referee for helping us to improve the paper. Our investigations were supported in part by the Netherlands Foundation for Research in Astronomy (NFRA) with financial aid from the Netherlands Organization for Scientific Research (NWO).
© European Southern Observatory (ESO) 1997
Online publication: April 28, 1998